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PROBLEM:
After languishing in the garage for a few months my Logitech Steering Wheel refused to work.

Plug in USB – both LEDs come on briefly, then the power LED goes off. Plug in power – right LED comes on and flashes slowly about 12 times, then continues to flash at double speed – no wheel movement.

SOLUTION:
The power supply is easy to check and mine was producing 24V as normal.

I decided to replace the driver ICs on the circuit board, These ICs are dual channel MOSFET transistors, the IRF7103 and IRF7342. I couldn’t source the 7342 so decided to try changing the 7103 only – the result when I powered on was a second or two of wheel movement then some smoke and a small flash inside the encoder motor. That was it! It seemed my motor (the left one with the encoder) was shorting out the power. I had measured the resistance across the motors and found that the one with the encoder was only 5 ohms and I almost gave up at this point but decided to open up the motor to see what caused the pyrotechnics.

The coils looked ok and the only thing looking wrong was a build up of carbon ‘mud’, in the gaps between commutator contacts. I cleaned this out and measured the individual coils – now all were around 17 ohms. I also cleaned out the left motor with some solvent spray and finally both motors measured 28-33 ohms. I applied 24V directly to each motor and they worked perfectly!

Spurred on, I replaced the 7103 MOSFET IC once again and… success, it drove the wheel. But only one way, I just needed to get hold of the 7342 IC and it could be a runner

DC motors are designed to run at high speed while power is applied and I think that’s where the problem lies with the Logitech steering wheel. In a previous life, I was a service engineer for Agfa imagesetters, which used two DC motors in a similar way, to tension film across a roller. In normal use they would move very little, so the designers incorporated a ‘motor cleaning’ routine that would simply run the motors at full speed for 30 seconds while the film was unloaded. This kept the brushes and commutator in good condition. Like a lot of other users my steering wheel wasn’t used for a few months and it was after this that it failed. I think the carbon dust from the motor brushes had turned into a conductive mud in this time (it was in a smokey damp atmosphere in my garage) and that shorted out the MOSFET transistors that drive them.

Finding a supplier for the IRF 7342 IC wasn’t easy so I bought the closest equivalent I could find from RS Components, this is catalog number RS 688 9137.

p1050979
Repaired PCB

These power transistors are the last thing in the chain, before the motor, so always very likely to be the cause of a stationary wheel. Once I changed the second MOSFET IC all was well.

I also discovered that if the encoder isn’t working, the motors will stop running – they will move, but not very far. If your motors run for any time then the encoder is probably ok.
For what it’s worth, opto-couplers like on the encoder will never emit visible light – it’s always IR.
On the Circuit Board, the component marked F1 doesn’t look like any fuse I’ve seen before but since there’s no resistance across mine it may well be.
Another thing I discovered, the hard way, is that the rack and pinion gears need to be aligned properly. I thought I had it working but after I put it all back together the damn thing wouldn’t calibrate. I eventually realised I wasn’t getting the full 900 degree rotation of the wheel – adjusting the way the gears meshed fixed that and it calibrated perfectly. The rack should move fully to the left and right.

I hope this can help others to get their wheels working again – it seems so wrong that so many of these go to the landfill for the sake of a £1 IC. Shame on Logitech for ignoring the problem and refusing to sell spares.

I’d also like to say, I am running F1 2010 on my iMac 27″ 3.06GHz Core 2 Duo and it works great. I have Windows XP on a Bootcamp partition with the game running at 1200×600 no problem at all. Running at 2560×1440 however wasn’t good.

DOWNLOAD my English translation of an excellent write up in Spanish by fellow wheel fixer sergioschumi.
Note this is a large 54MB file with HiRes photos.

170 Comments

  1. johny

    Hi,

    Good to read your post, I had exactly the same problem and found out the MOSFETS were all burnt. I replaced both IRF7103 and IRF7342, and after I plug in first power and then USB, the wheel still move to the extreme of right and never turns back, and there is no change in the x axis reading. Is there anything else you have replaced?

    Regards,
    Johny

    Reply
  2. macnetwork

    Hi Johny,
    I must admit I didn’t find it easy to get those tiny little ICs soldered on and it took a few attempts to make it work. In the end, I wore three pairs of reading glasses to get a close up view and used a flux pen to get a nice flow of solder. I think the chips may be quite sensitive to heat, so maybe it’s worth another go – but be quicker this time!
    I had the same one-way drive before I changed the second IC so I think your symptoms point to a bad MOSFET.

    Good luck and do let us know how you get on.

    Reply
  3. Gio

    Hi Johnny!

    Investigating a weak feedback on my wheel and I suspect the motors may be at fault.

    I measured R whilst turning the motor very slowly by hand. Lowest reading is 26.2 Ohms. Is that within tolerances?

    Also did you manage to get the casing out and access the innards? The reason I’m asking is because you mention that you cleaned the motors out and that you could see dust on the commutator…so did you literally just soak them in contact spray (is this safe to do?) or did you open them up and cleaned them?

    Nice write up BTW, surprising how badly build the G25 is considering it’s a top of the range wheel! I’m shocked at the poor wiring and components used! + I have had all the common issues with it! Dodgy gearchanges, dodgy pedals and now dodgy force feedback! + The plastic that holds the bearing had cracked! This wheels is worst than my Alfa!

    I do wonder if perhaps I would be better off selling it and going for a Fanatec! Specially when the dual motor set-up means a really poor middle deadzone!

    Reply
  4. macnetwork

    Hi Gio,
    Yes, I took apart the motor but at that stage I had really given up hope of fixing the thing, so it was really just to satisfy my curiosity. I made a mess of dismantling it, bending back the metal tabs that hold the end plate. Even so it went back together and still works great. The other motor, I just soaked in switch cleaner and that restored its resistance, so I wouldn’t recommend dismantling them. However there’s a metal sleeve that can be pulled off to gain better access to the brushes and commutator. Poking in there with a cocktail stick might help clean out the grooves. 26.2Ω seems a bit low but I’m no authority on the subject.

    Reply
    • Gio

      I used a cotton but I didn’t realise that it was the grooves that needed doing!

      The motors are probably on their way out so I looked at replacing them. I have some RC car motors that usually run on 7.5V. Only problem is that they are super-duper top of the range 20,000 rpm and something ridiculous like 15-20A and the torque of an american V8!

      Do you reckon I could just wire them up? I’m a bit rusty on the old electronics but I am a bit worried the power mosfet won’t be able to handle the power.

      Altough I’m thinking that the motors will just use up the current/voltage that is given to them? Will they just turn a bit slower (which in this case it’s good!) or will they fry the electronics (maybe a zener diode is in order!)

      Reply
    • Luis

      My 7103 broke again (didn’t last more than a couple of hours of gaming after replacing both mosfets) after exhibiting a very weak force feedback while playing Snowrunner.

      The right motor (with decoder), after cleaning, measures 18ohm while the resistance for left motor is 30ohm. Could this be a cause for the 7103 so quickly? Can/should it be replaced with a stronger MOSFET?

      Thanks.

      Reply
      • John

        Hi Luis, I would suggest you try to have both motors measuring closer to 30ohms before replacing the MOSFET again.

        Reply
  5. macnetwork

    Yes, it’s the carbon dust in the grooves that is shorting out the power to the motor.

    I think you would need identical motors. Your car motors could blow everything and the force feedback is unlikely to be correct without near identical specifications. Of course, in use the motors hardly rotate at all, they are used more to stop you turning the wheel and to vibrate it, except for the power-on calibration.

    Reply
    • Gio

      I shall have a look at cleaning the motors again!

      Reply
  6. Spooke

    Hi, I bought both mosfets and replaced them. Also cleaned one of the motors as the other was fine.

    Plugged it all together and it was calibrating but really slow and smelt like burning.

    Any ideas one what is wrong? or will I have to get a new wheel all together?

    Thanks

    Reply
  7. macnetwork

    It sounds like you’re not far off fixing it but my only experience is with low resistance motors. What did you measure across the motor terminals? It needs to be more than about 26Ω I would say, if it’s lower than that maybe the cleaning wasn’t thorough enough. As a check, you can connect the 24v power supply directly to the motors to see how they run (polarity doesn’t matter).
    Also I suppose another component on the PCB could have a problem.

    Reply
  8. Spooke

    I cleaned the motors again today, both are at 29.xx Ohms, so they should be ok?

    I plugged it all in again and it starts to calibrate at normal speed but goes to the right and then left and stops, it doesnt return to the center like it should.

    I have tried that with the motors and they spin like normal.

    Do you know what could be wrong now? As I said it calibrates at the normal speed it should and does not smell of burning but it goes from right to left and loops.

    Thanks for your help 🙂

    Reply
  9. John Hunter

    Hi Spooke,
    I had this problem when the rack and gears weren’t meshed properly. Can you turn the wheel the full 900º by hand? If not, something is wrong. Please refer to the write up by sergioschumi mentioned above to see how to align the gears.

    Reply
  10. Spooke

    Oh right, I did notice that it didn’t fully go to the end of the rack. Will re-align it tomorrow, hopefully it fixes it.

    Thanks for your help, will post up whether it works or not 🙂

    Thanks again

    Reply
  11. Spooke

    Just to let you know the wheel is working perfect now 🙂

    Thanks for your guide and help

    Luke

    Reply
  12. macnetwork

    Great news Luke, so glad you got there in the end. I hope it will inspire others to persevere.

    Reply
  13. dguillot

    I just bought a G25 with pedals shifter and wheel for $100.00 usd with this similar problem. I thought to give it a go at repairing using your technique. I should have the wheel next week, and keep you informed of progress. I’ll see if it was a wasted $100.00 usd Thanks much.

    Reply
  14. Rafael Santos

    Hi. I have a problem here with my G25. It was working fine, but while cleaning the interior I accidentally gave a short on the motor connector and now the wheel is not working properly. All the buttons, pedals and shifter are working, but the motors aren’t turning and the board is not receiving information from the encoder.

    The LED in the encoder is working (I saw it with my camera) but when I turn the wheel nothing happens. Has it something to do with the short in the motor? Is there a chance of the short have damaged the main IC (72F651)?

    Can you help me here?

    Reply
  15. macnetwork

    Hi Rafael,
    Oh dear! It sounds like you effectively simulated the failure I and others have had, so the previous repair info may well be relevant, although my motor only went down to 5Ω. I don’t know what damage a short circuit would do but it’s probably best not to clean the thing while it’s plugged in!
    I think the main controller IC would be okay though as the motor power doesn’t come through there, it is only controlling the MOSFETs which are connected directly to the power supply and almost certainly fried!

    Reply
    • Rafael Santos

      Actually I cleaned with the power off, but I made a mistake when mounting that I just saw after trying powering and realising that was not working.

      The MOSFETs I’m sure are demaged and I already ordered both 7432 and 7103, three of each, just in case. I also ordered the comparator LM393, even it is not likely to be demaged.

      What I’m really worried about is that the board is not receiving information from the encoder. The white and the black cord from the encoder cabe are the signal and I measured the voltage while turning the codewheel slowly with the hand and it looks like it is working, since it is changind from 0V to 5V alternately.

      I also followed the signal from these cords and they go directly to the controller chip. That is why I’m suspecting of a damage in it. What do you think?

      How did the encoder behave when your wheel was demaged?

      Reply
  16. macnetwork

    On the PC you won’t see any response from the steering wheel if it didn’t complete its initial calibration – that’s the rotation back and forth to the extreme ends on start up.

    (This is why the steering wheel is useless if the MOSFETs have blown, otherwise it would still work for steering, but without force feedback.)

    So I wouldn’t worry about the controller but please let me know how you get on with the repair.

    Reply
    • Rafael Santos

      That is GREAT news. I didn’t know that. It was making no sense at all to me because neither the encoder nor the controller have nothing to do with the MOSFET session of the board. What led me to this mistake is that all other buttons and the pedals work even without the calibration. But now it is clear.

      Now I’m confident I can fix it. Tomorrow my chips arrive and I will let you know how it goes.

      Thanks for the tip man.

      Reply
      • Rafael Santos

        It lives!

        Your tip about the encoder was essential. I was almost giving up the fixing before you told me about calibration thing.

        I just replaced the MOSFETs and it is back.

        Thanks again.

        Reply
  17. Rafael Santos

    Hey man, that’s me again.

    The wheel is working fine now. But I decided to make a full modification in it including the motor. Instead of 2 weak motors I’m gonna use 1 stronger motor.

    The G25 motor has a 0,5A max current, which means 1A since it has 2 motors. I was reading the datasheet of the MOSFETs ans it says that both 7103 and 7342 has Id max of 3A. Do you think I will have problem connecting a 2A motor in this board?

    Reply
    • macnetwork

      Sounds like a recipe for disaster to me! Circuits always use components that have wide tolerances and even then, as we all know, the motors can overload them in extreme conditions. Also manually turning the wheel actually generates high voltages and perhaps more powerful motors could damage the circuits. The extra torque generated could also have a bad effect on gears and other physical parts in the wheel.

      Reply
  18. Jenkins

    Hi. My G25 is having almost the same problems.
    Made an electrical smell (Reminded me of AFX Scalextric) then FFB went funny. Unplugged, plugged it back in and will no longer give any feedback. Gives me a dim power led, would flash the first few times I tried but not anymore. Power cable is still fine and gives 24v.
    All buttons still work and the wheel will still be recognised and turn left and right in game, providing I manually calibrate (Turn all the way left, all the way right and center) it first.

    Would you reccommend the fix you posted with changing the MOSFET for my problem?

    Reply
  19. macnetwork

    I am trying to relocate this blog but anyway I’ll carry on here for now.
    I’m very interested to hear that you managed to calibrate the wheel manually, is there some trick to that or did you find it easy?
    It concerns me that your Power light isn’t on and flashing as described at the top of this article, as far as I’m aware this is what always happens if the MOSFETs are blown. I would check the large diodes at the top of the board, I suspect they have something to do with the way the FFB works with the motors’ back EMF, although I am guessing.

    Reply
  20. Jenkins

    It would rapidly flash at first, then constantly flash slowly once a second. When I tried again the other day the power led would only stay dim.
    When I got the wheel recognising left and right the next day, I think I just plugged the power cord in (No change on led) then by hand went all the way left all the way right and it just worked. I could still drive after unplugging the power cable too.
    I gave it another shot just before but I can’t get it to work again.
    I’ll be opening it up later on, If I get it working Ill post back on how.

    Reply
  21. Adam Yamada-Hanff (@AdamsAutoAdvice)

    My Logi steering wheel isn’t working either! Sounds like a similar issue. However my unit is an older model for PS2 the Driving Force Pro. Any tips on how to fix it?

    Reply
  22. The Animaster

    I had the same symptoms as above — upon calibration the wheel would just jerk slightly and then the power button would go flashing.

    It wasn’t the electronics.

    It was the encoding wheel that is located on one of the motor spindles. This wheel’s movement is read by IR. Logitech uses some p*ss-poor plastic for the encoder, and the encoder tends to crack not in just one place — but THREE. Essentially, you’d need to get a replacement for this little piece of plastic which renders the whole unit unusable.

    I’ve managed to get a laser service shop to cnc a replacement out of brass. If posting URLs is alright, you can find them at http://cmlaserservice.com/page_home.html. They sent me a prototype and it works. Still testing it — but everything checks out.

    If you can confirm that it is indeed the encoder wheel that is broken on your G25/G27 (by having a look at the encoder wheel), I suggest emailing these guys for a replacement if your unit is out of warranty (or if you’re tired of Logitech sending you units that just keep breaking).

    FYI, the encoder wheel is meant to fit snugly onto the motor spindle, it should NOT rotate freely, independent of the motor spindle. If it does, then either it’s cracked, or wasn’t moulded properly.

    Reply
  23. The Animaster

    Err.. I meant the power LIGHT, not button. When it flashes it means there’s a problem… could be a whole range of problems. Logitech doesn’t exactly want to list them all down for us.

    Reply
  24. The Re-animator

    Could you describe the encoder wheel in more detail or perhaps link to an image?

    Reply
    • The Animaster

      The link above now has a picture of the encoder (they make). The one in the G25/G27 is made of black plastic.

      Reply
  25. Andrew

    This worked perfectly for me! many thanks for the guide, I had problems de-soldering the Mofsets & ripped one of the tracks up from the board, luckily i didnt break it 🙂 wheel worked perfectly afterwards 🙂 was sure it was for the bin at one stage!

    Reply
  26. Jenkins

    I gave my motor a clean like in the guide however I can only get 25Ω. Will that be enough?
    Does it mean the motor is too worn?

    Reply
    • Andrew

      After cleaning mine was only at 26 ohms it worked afterwards though easy way to check is leave the controller disconnected & apply 12v directly to the motor to see if it shorts….

      Reply
  27. macnetwork

    Hi Peter,
    The D2 is no good for the Logitech because there’s a diode instead of a second MOSFET. Any of the others will probably work fine, the PbF simply means ‘Lead Free’ which is great for the environment but probably makes soldering harder. I see there’s another, the IRF7342QPbF which is qualified for automotive use – sounds perfect for a steering wheel!

    Reply
    • Peter

      Thank you! I will get it soon as possible. If it’s works out, I will let you know.

      Reply
  28. Peter

    I got the IRF7342PBF IC today. Oh boy! It is tiny. I have to find someone who will able to replace it for me. I will reply about the result,hopefully this week,

    Reply
    • John

      Hi Peter,
      I managed to solder it with my old standard soldering iron–yes it’s near impossible and not recommended. Have a look at ‘Hot Air Soldering’ on YouTube and see how easy it could be.

      Reply
  29. Gaz

    I’ve been testing my G25 today and everything is fine as far as I can tell apart from the motor without the encoder.
    It’s reading 2.5 ohms but the other reads 31ohms.

    Is it too far gone to even bother cleaning?

    Reply
    • admin

      It’s hard to see how contamination from worn brushes could affect one motor so badly yet leave the other with a correct resistance. Make sure it’s disconnected and you’re not measuring the MOSFET, If you are getting 2.5ohms with it disconnected I’d say there’s another problem like a short in the windings. You could try measuring the voltage generated by the motor when you turn it–this might indicate whether there’s any hope.

      Reply
      • Gaz

        Is the mechanism supposed to have quite a bit of resistance to it?
        For some reason i keep thinking that before it broke, the wheel would turn rather easily when its disconnected.
        Now it takes some force to actually turn it.

        Reply
        • admin

          With the wheel unplugged there’s little resistance to movement apart from the weight of the wheel. But I reckon if the motor was working and you put a short across its terminals it would become much harder to turn. Basically because you’re generating a current when you rotate the motor.
          So maybe your motor is okay but the MOSFET it’s normally connected to is shorted. Try a 12V battery directly on the motor to see if it runs. The usual power supply is 24v so hopefully nothing will catch fire!

          Reply
  30. Gaz

    Just connected a 12v battery to it and something inside near the top immediately started glowing or caught fire, then there was a bit of smoke which smelt the same as it did last night when it stopped working.
    It does still run though and the other motor is fine.

    Reply
    • admin

      Sounds promising Gaz – just like what I had and describe at the top of this article. I think you need to clean out those grooves in the motor commutator. But of course I also think your MOSFET is likely to be blown.

      Reply
      • Gaz

        The motor is all cleaned out now and its back up to 30.6 ohms.
        Thanks for the help and the great guide.

        Reply
  31. mike

    Great guide thanks. However it seems I have killed my g27. I followed your guide took it apart checked the mosefs they weren’t blown. Cleaned the motor and noticed three hairline cracks on the encoder. I didn’t have any calibration issues but weak ffb to the point it felt like I was running at 10% when it was over 100 in game. So after cleaning DC motors (taking cover off was pain in the…).. I gently put it back together and now when I turn it on I get small click noise from the encoder and ffb motor on encoder and nothing. The power light flashes green and it just clicks over few times and nothing. Did I short the motor?. Is it the encoder?

    Reply
  32. admin

    Hi Mike,
    It sounds like you had a different fault to mine and that maybe the motors were just a bit weak. It’s worth checking that they run okay by applying 12V DC before bolting them back in place. Your issue now sounds like The Animaster (May 2012 post above) –if the encoder wheel is slipping on the motor shaft, I think you’ll get those symptoms. Try repairing the encoder wheel or buying a replacement?

    Reply
    • Mike

      Thanks for reply.
      Applied battery and motors work. Then I applied some super glue on encoder and that worked too calibrated perfectly. Took many tries to get wheel to calibrate kept hitting the stop piece at end (doh!) didn’t watch where the gears sat in center properly when I opened it first time.

      Wheel works now however with side effect, I ended up greasing the gears on wheel and the big plastic piece of gears it rides over and now its spins way too easy. FFB is almost gone completely. Should I clean the grease off or is this ffb weak due to motors?

      Reply
    • Mike

      Just to add one more thing. The right motor without encoder is registering 26 ohms and the left one 22 ohms after cleaning. So not sure if this is just the extra amount of grease that got it light?

      Reply
      • admin

        Have you checked the two big diodes Mike? I think that they effectively short out the motors, making them hard to turn. But mechanically everything should be light and free running so no I don’t think too much grease is a problem and with no power applied the wheel is actually very light and free running. Is 22Ω a little low perhaps?

        Reply
  33. Jonas H

    Hey guys, Great write up! I currently use a G27 and i have an old G25 that kinda flamed on me a good while back, i left it on the shelf thinking “some day” and then my GF bought me a G27 bless her heart.

    So… after reading this i took out my old G25, it’s in bad condition and the motors were reeeally stiff to turn and i got about 4-8 ohms on both of them, cleaned them out and gave them some lube (no bearings just bushings on these motors) and woila! silky smooth 24-27ohms on both and they run just fine on 24V (before they just sparked and smelled funny hehe)

    one of the fets are clearly blown so i will need to replace them.

    Which leads me to my question.. if i am to build a complete new wheel using the G25 internals but with an all aluminium frame and converting it to belt-drive, what is required on the fet-side and possibly the diods to make it run with say for instance 35-40volts ?

    surely it can be done since ARC is doing something similar.

    Any tips would be awesome, experimenting with this old wheel will just be a fun project since i have my G27 on my main rig =)

    Let me know if you have any tips on components or what not.

    Reply
  34. illan

    Great guide! I had the exact same problem, followed this guide and now my wheel is working again. However after I replaced the MOSFETS my H-shifter is not working, it’s completely dead, no lights, nothing. Wheel and pedals are working fine. I really don’t know what caused this or what I should be looking for, any ideas?

    Regards

    Reply
    • John

      Hi illan thanks for your comments. I haven’t seen that problem with the shifter but I’d guess it’s a damaged cable or maybe the computer software? Should be easy to check for continuity down all the wires in the cable to the shifter and that it gets to the PCB. I haven’t opened the shifter so you’ll be pioneering that one!

      Reply
  35. Joco Gorenc

    Thanks for this guide.

    I have pretty much the same symptoms described. Buttons and pedals work, when plugging the wheel right led flashes, no steering detected and the wheel has more resistance when trying to turn it.

    Opened the wheel and I found no visual damage. Power supply adaptor reads 23.2V, tried a reserve one with same current and it has 23.5V.

    I’m pretty sure the mosfets are gone, maybe the motors as well. And good guide how to read the motors’ ohms?

    Thank you!

    Reply
    • John

      Read the whole thread Joco it explains how to measure or test the motors and don’t overlook the PDF guide. It’s translated from Spanish but very thorough.

      Reply
      • Joco Gorenc

        Ohh, I somehow overlooked the PDF guide.

        One more question…if the mosfets are burnt, would there be any visual damage?

        A friend that knows these things said it’s most likely the motor’s brushes(not sure this is the word in english) failed thus the higher force when turning the wheel.

        Thanks

        Reply
        • admin

          There isn’t normally any visible sign of damage on the MOSFETS.

          Brushes is the correct term but in the Logitech wheel they don’t tend to wear out because the motor only gets to spin when calibrating at startup, most of the time it’s fairly stationary. But it’s a small amount of dust from the brushes that clogs up the grooves in commutator and causes the short which blows the MOSFETS.

          Reply
          • Joco Gorenc

            OK so I have sent the wheel to someone who has the tools to replace the MOSFETs properly. I will let you know if it worked. Fingers crossed!

  36. Thorsten

    When you open your Mabuchi motors (to clean them), be very careful not to break the carbon brushes.. ! You can easily prevent this, when you take 2 paper-clips, that fit into both slots close to the pivot/anchor of the motor.
    By pushing those 2 paper-clips together to the center, the brushes are forced to “open”, so that you can remove the cap, without hurting (or destroying!) the carbon brushes.

    To open the motor: I used a dental bur/drill to cut away the “legs”, that are bent over the cap. Afterwards I placed 2 screws (laptop diameter) in the 2 open threads and carefully pulled the cap off remember the brushes; wire the paper-clips into place or use a rubber band. Check out, if the legs of the bushes are still open, BEFORE you apply any force to the cap, or you will crack your brushes 😛 You can later on use a soldering iron and some flux and put some tiny solder dots to fix the cap right in place.

    Hope this helps somebody – to prevent another “fail”/more damage to your G25/27.
    Good luck and happy driving (again)!

    Thanks to the Admin to share this to others..

    Reply
  37. Marc

    Hi,
    I have got a very big problem with my G25 board:
    Since I tried to replace the mosfets the G25 doesn’t react anymore, so it is not recognised by the computer and the buttons are not working either. Is the main IC so sensitive that I could have destroyed it by heating up the board with the hot air gun or do the Mosfets also have to do with the buttons? Would it be possible to replace the main chip?
    Kind regards,
    Marc

    Reply
    • admin

      Hi Marc,
      I would think that the computer would recognise the wheel even if the MOSFETs were removed completely but then again, I haven’t seen the size of your heat gun! The MOSFETs only function is to feed the power from the supply to the motors – they are like a tap that is opened and closed by the big controller IC.
      Do you think the Power Supply is still okay? Do the LEDs light up? Have you checked all the other connections and cables in case they’re not back correctly.
      I doubt that you could obtain a new main controller IC as I would think it’s Logitech’s own custom chip

      Reply
      • Marc

        Hi,
        thank you for answering so fastly. Yes, I have checked everything. I think the board should be recognised even with only the USB cable plugged in as I did it.
        Do you really think it’s a custom chip from Logitech? For me it looks like a universal chip. If that’s true, do you think it would be possible to load the G25 firmware to a new main IC?
        Kind regards,
        Marc

        Reply
        • admin

          You are correct it is recognised with only the USB cable connected and the LEDs on the stick light up. What’s really annoying is that Logitech don’t supply replacement boards – forcing users to throw away perfectly good steering wheels for such simple faults. Replacing or reprogramming the main IC is way beyond my skill but maybe someone else has tried it?

          Reply
  38. Cor

    Hi,
    Seems that a lot of Logitech owners having the same problems, and yes so do I.
    Cleaned the motors an having plans to replace the mosfets. I need to order these in a few days.
    Question;The diode on the right side next to the right motor connector has no resistance. The other diode on the left reads approx 12 ohm.
    I have plans to replace the right one but before I’d like to know the value of the diodes.

    Reply
    • admin

      Hi Cor,
      Have you removed the diodes from the board to test them? You should be able to read the part number off if you do but I suspect the readings you’re getting are affected by other components on the PCB. I don’t think anyone else had to change their diodes.

      Reply
  39. Cor

    Hi,

    Today I found an address for replacing the mosfets, they will solder them for an amount of 17,- euros, mosfets inclusive.They will check the diodes as well.
    It’s about 50 miles from my address so I sent the board by mail.
    Let you know if everything works out. Keep you posted.

    Regards,

    Reply
    • admin

      That sounds like a good deal. Thanks, it would be good to hear how you get on and maybe share the address for this repair shop if they’re any good.

      Reply
  40. Cor

    Received the board back yesterday, parts replaced on my request.
    Test it today without success. No calibration, start-up or reaction by Logitech’s monitor program in Windows. All usb related buttons working, except the steering wheel. Replaced optical sensor aswell but still dead.
    Will contact the people next week who made the repair, best is to send the complete wheel to find the problem. Probably more damaged than mosfets only just like yours.
    They did an excellent job b.t.w. by soldering the items on the board.

    Reply
    • admin

      Drat! Have you checked F1 on the board for continuity? I believe it’s a fuse.

      Reply
  41. Pete

    I’ve also read this great thread. Managed to take both engines appart as my G25 started feeling real notchy. Cleaned the sensor side motor. All silky smooth now. And also cleaned the 2nd motor, but it remains very stiff. Put it all back together. Still calibrates but feels very slow and when calibrating 2nd motor (non sensor side) the one that sticks starts smoking…maybe too much contact spray shorting the windings?

    Any clues for finding two replacement motors for this old g25?

    I don’t think its the electronics on the PCB, just the motors.

    Much obliged.

    Pete

    Reply
  42. Jimbo

    What I did :

    Cleaned motors to 30 ohm’s

    Changed mosfets and replaced transistors ( MMBT3906 ) on board location Q12 & Q13

    Checked voltage on optical encoder ( read 0 – 5v ) so ok and looked at ir led with phone camera ( ok )

    STILL NOTHING ????

    Then bridged the F1 Fuse ( Green One ) with small wire to test

    IT WORKED !!! Wheel calibrated and feedback fine

    So the F1 fuse is important and the info on the fuse is as follows :

    Littelfuse 31/2a 250v

    Hope this helps someone

    Reply
  43. Jimbo

    UPDATE :

    Fuse is Called a Pico Fuse

    2A / 250v

    Can buy them on amazon uk / ebay uk / rs components

    Most are rated at 125v but not sure if it needs to be 250v

    Reply
  44. tare

    Hi, my g27 motors getting very hot{can barely touch them} after a little and FFB decrease, what s the problem and what can i do???are the motors replaceable?

    Reply
  45. André

    Hi, i have a issue similar to you. i already change the 7103 fet but it stills hot every time i plug the PSU.Can you help me?? Do you know who can repair it? Wait for your reply.
    Thank so much.

    Reply
  46. Krusty2

    Could you help me with my G25, please.
    Problem: Nothing happens when plug USB to PC.
    Nothing happens when powerSupply gets attached.
    No LEDs on in shifter.

    PowerSupply gives 24V, so thats ok.
    Measured Fuse and it’s seems to be ok. No resistance between legs and when powersupply connected gives 24V from other leg.
    Measured IRF MOSFETs pins like translated PDF guide says and seems ok.

    Also measured motors and those had both atleast minimum 15 ohms.
    By the way, should those be measured from connected to main board?

    Should I try to clean those motors and so having same problem that many others?
    But my wheel seems to be like dead. No calibration, PC does not recognize wheel at all and no flashing leds etc.

    Reply
    • admin

      Hi Krusty2,
      It sounds like you have other problems than just duff motors, they don’t affect the LEDs and your PC should still recognise it as a G25.

      Reply
  47. Jamie

    Anyone know what capacitance the C44 capacitor is? Its the one underneath C43 on the right hand side of the 7103 MOSFET. I knocked it off while soldering a new 7103 on and surface mount capacitors aren’t marked with any ID, plus I don’t have a capacitance meter to check…

    The closest I can narrow it down to is between 1nf and 100nF, picked up from Wikipedia’s info on surface mount components (you can partially tell capacitance from the colour of the capacitor).
    Otherwise my G25 is for the bin 🙁

    Reply
    • Nicolas

      Hi Jamie,

      I’m currently fixing my G25 as well and my C43 capacitor is shorted. I think this is the same capacitor as C44. Did you find the proper value that worked with your C44 ?
      Thanks a ton.

      Reply
  48. admin

    All I can suggest is you try 1nF and work your way up. Caps aren’t normally that fussy about exact values – so try 10nF and then 100nF

    Reply
  49. Pete

    OK i managed to get 2nd g25, this one has good engines. 30 ohms all around, but it calibrates only one to the right then stops. Should i try to replace both mosfets on this PCB?

    My other g25 PCB I think I killed by keeping it running with 1 faulty motor. It sparked a lot and then stopped calibrating all together. I measured over F1 on this board and don’t think the fuse has popped. I replace both Mosfets but still no life. Could it be the diodes at the top are dead? and how would I verify this? I prefer to get this PCB working before I start soldering the other one.

    Thanks for input!

    Pete

    Reply
    • John

      Hi Pete, if you look at the second comment on this thread you’ll see I had the same one-way drive issue before I changed one of the MOSFETs a second time.

      Reply
  50. Pete

    The conundrum for me is though, this wheel showed both motors to have 30 ohms or resistance so why would one of the mosfets fail. I guess ill just have to take both off, replace them and see if the board works again. I would like to get the other 2nd board working too again, wondering what other components I might have fried and how to measure this with a multimeter.

    Reply
  51. Pete

    Ok I’ve replaced both MOSFETS on board to. I measure resistance over MOSFET 7103 4.11 kilo ohm and 4.63 kilo ohm. 0.00 over the other 2 sets. And for MOSFET 7342 2.22 and 2.23 kilo ohm, 0.00 for the opposite sets. So I assume those are all good.
    Wheel will still only calibrate clockwise. Then stop, will not turn counterclockwise afterwards. No calibration happens when the encoder motor is dis-coupled from the PCB, so ïm assuming the circuitry powering the non encoder motor is not working. Which components should I check and might cause this malfunction? Seems that the MOSFET’s where not the culprits as symptoms are same after replacing both.

    Hope someone can help me out trouble shoot this PCB, perhaps with a working PCB so i can check with multimeter components and check my values against theirs??

    Much obliged.

    Pete

    Reply
    • John

      Pete, can you manually turn your wheel turn 900 degrees?

      Reply
  52. cr3ativ3

    I just fix my Logitech G25!!!! Thanks for this awesome tutorial!!! If someone needs, I can give U pictures with the MOSFET I bought. Thank YOU again for the tutorial!!!Sorry my english…

    Reply
  53. Pete

    Yes i can turn my wheel manually 900 degrees at one point it even calibrated.

    Does anyone have the part nrs for the two transistors and the 3 diodes? I will try and replace those. Much obliged.

    Pete

    Reply
    • John

      Pete, you should be able to read the numbers off those components. Diodes are easy to check with a meter; current flows straight through them but only in one direction. Multimeters normally have a diode testing mode and will beep with the terminals one way across the diode but not the other way.
      From what you say I wouldn’t suspect the diode – they aren’t a component that works one minute and not the the next. Have a very close look at the encoder wheel and optocoupler – that might be a more likely cause. Is the encoder cracked or loose on the spindle?

      Reply
  54. Edson Duarte

    I have a G25 and was more than a year no use

    When I connected the PC, pedals and the march were ok, but without steering wheel signal.

    Does anyone have any tips on how to find the defect?

    grateful

    Reply
  55. snoopy

    Hello. First of all thank you for the info you provided, im pretty sure it helped alotta g25 users around the world. Can i get some further help here? My second g25 has a problem. Everithing works perfectly except ffb (ffb turns left only). If i manually calibrate it works ingame and i can drive if turn off ffb. I tested motors both are ok and resistance is about 30+ on each of them. I took tester and compared both pcbs of my two g25s. I noticed that right mosfet (7342) is dead. I replaced it but did not help. Later i noticed that something wrong with r50 and q13 details on that bad wheel. Can someone tell me what that details called? Wich parts (number?code?) should i search to replace them. Maybe someone have faced that problem before..
    Thank you. And sorry for my language (long time no practice):)

    Reply
  56. Snoopy

    Just now replaced IRF7342 and MMBT3906 that was dead too. Connected all stuff. Same thing: wheel rotates to left untill it locks and thats all.. Then replaced IRF7103 (thought maybe it could help). Connected all stuff back again. SAME $#!T!!! Wheel trying to calibrate to left, then stops and ffb is relese like it wants to turn back, but no power applies to the oposite side. WTF is wrong with that wheel? Optical incoder is ok all stuff is ok. It’s something wrong with mainboard. I tested it on my second g25. Same story. Which part on PCB is responsible for swiching power on motors back and forth? I guess thats the problem but i can;t figure whats that. Mabe main chip (processor or whatever it called) is screwed somehow?

    Reply
  57. Supersteve2345

    @Snoopy that sounds a lot like the problem I’m having with my wheel too.

    Reply
  58. Supersteve2345

    So it seems it’s a case of replacing my mosfets and cleaning motors.

    My wheel will power on Rotate to the right then to the left and hang there, repeats 2 more times then gives up. I’ve checked both motors and 1 is really really slow so I think that’s what caused my wheel to break. I was playing Test Drive Unlimted 2 on fairly high FFB than I normally do (Only other game I regularly played is Euro truck Simulator 2 on really low FFB) I smelt a burning smell and noticed my wheel was off centre so I quit the game and disconnected controller and reconnected and now all it does is this. I initially thought it was my encoder disc so ordered a replacement from CM laser to no avail until I came across this guide.

    Reply
    • Snoopy

      It worked out for me. Replaced mosfets (it took few attempts and a couple of fried out new mosfets hehe). Now my G25 as good as new.

      Reply
  59. Nicholas

    So what mosfets could handle 48V in the G25/G27 like the ARC mod used?

    Reply
  60. Naz

    Hi i had a same problem with my G25. All button , shihter calibration all working its only steering wheel not responsive. today i had received IRF7103 dual mosfet and replaced it but its still doesnt work. bridge F1 fuse still not working. waiting for my IRF7342 dual mosfet.
    is there anything i missed out..thanks in advanced admin

    Reply
  61. Erhan

    Hi there.

    My G25’s motors are dead.

    Can I change them with any dual shaft motors like mabuchi?

    “12VDC RS-540SH-32105 Dual Shaft” on forums they wrote this motor for use.

    It’s 12V and power supply is 24v. If I change power supp. with 12V DC 2 Amp. will it work? or should I find dual shaft 24v DC motor to use?

    Does the “RPM” important? Should I find likely Johnson’s motor RPM equivalent?

    Thanks for your answer.

    Reply
    • admin

      Hi Erhan, you say both motors are dead how did you manage to kill them both? Have you read the whole thread here and tested the motors, because it sounds like a typical MOSFET failure.

      Reply
      • Erhan

        Thanks for your answer.

        Firstly I changed mosfets. After that I’ve cleaned motors.

        When I try, one of the mosfets is dead.

        One of the motors is working for now. I’m using like this (not full power of course).

        Also I check circuit board. I’ve changed fuse.

        For now I need motors.

        Reply
        • admin

          Erhan, I don’t follow your logic. It’s dirty motors that blow the MOSFETS so you must clean the motors and hopefully get them near 30ohms before you change the MOSFETS otherwise they will just blow again.

          Reply
  62. Anton

    Hi
    I have Logitech force pro wheel. I assume that circuit board is very similar to G25 one. I have similar problem with this wheel but with further inspection of board I spotted that 5 small N-FET transistor are burned ( they have visual damage on his surface ). My question is how I can identify their mark ( like : BF545C or MMBF5486 for example ). Suppose I need circuit board blueprint. Any help is appreciated.

    Reply
    • Snoopy

      Did you found out what was the index/mark/model of your FETs? If not why not try to use G25’s if PCB is similar to each other?
      I’m just asking, this is not a recomendation (just to remind you: everything you do – u do at ur own risk.)

      Reply
  63. Luca Weltert

    Hi there, I just bought a used modded ARC Team Logitech G27, nut force feedback seems crazy and gone.

    I went through the full article, found it quite interesting, however the more i read the more it seems to me my problem is unique.

    I post here a link to a short video illustrating the problem.

    https://www.youtube.com/watch?v=XIIU8aOWIAQ

    If motors were gone they should not turn at all I guess…… moreover the position of the wheel after sort of calibration is correctly read, so it’s not the optical encoder, I guess.

    The fans keep stopping and going, I thought to a power supply probel, resoldered the cable and checked isolation and voltage: it gives 41.6 v and isolation is good.

    Any clue to what should I start troubleshooting ?

    Reply
  64. Shane

    Hi guys,

    My G25 gave out on me last night and after reading a few threads and watching some videos on You Tube, I found your page which has seemed to help so many others. My problem is however somewhat different, my wheel pulls hard left and stays there. I can pull the wheel manually to the right with a lot of effort but as soon as I let go it goes straight back to the left again.
    Do you think your solution would be able to fix my issue?

    Thanks.

    P.S. All buttons and pedals work fine in the profiler but there is no wheel feedback.

    Reply
    • admin

      Shane, you say there’s no wheel feedback – I think you mean there’s no positional information rather than no force feedback – in which case I would say there’s something wrong with the encoder on the left motor shaft. There’s some comments here about that problem that might help.

      Reply
  65. Snoopy

    Hello, it’s me again. Have new problem with G25. My G25 was turned on without one motor (i know it’s me and my friend’s fault). After that it don’t calibrate. The power led is blury shining. Same as if it connected to PC without power unit. But strange thing is going on: small FFB effect is left. But whats more strange thing is that if I even disconnect all wires from PCB (even power) except two motors – motors still produce some FFB. It looks like some power accumulated in condencer and still make FFB effect. But i’m not 100% sure in this. Can someone give me advice am i right? If so – then i’ll just replace condenser. Oh yeah and BTW, when power is connected to PCB it makes warm around condenser and near mosfets. Maybe it’s fets also? Any ideas?)
    Thank you.

    Reply
    • Snoopy

      Solved! Later that night I was thinking of problem i got.. I tried to disconnect different wires ans so on. Well the problem was in mosfets again. And FFB effect was just power producing by motors (when manually turn hub) getting back as FFB on itself. Hope my experience will help someone later. Cheers.

      Reply
  66. Marc

    Hi,
    I’ve got a quite strange problem with my G25:
    When I plug it in to my Computer with power supply attached the wheel moves very shortly and not very far, it tries that another two times and then it stops. It’s the same phenomenon like the optical sensor pcb was not connected to the mainboard. All buttons and pedals are working absolutely fine. The encoder wheel does not look broken in any way and the optical sensor pcb seems to be working as well as the voltage changes when I measure voltage of channel a and b, but for some reason the mainboard does not seem to be accepting the data of the encoder.
    Could it be that the main ic of the mainboard is dead although it’s recognised by the PC and all buttons and pedals are working or could it be the optical encoder pcb which has a problem?
    Kind regards,
    Marc

    Reply
    • Marc

      Ok, I solved the Problem by just turning the cables of the motors on the mainboard.
      For me it seems quite rare that it matters in which direction the Motors are turning when plugging the usb cable in, but not it’s working absolutely fine 🙂

      Reply
  67. Roberto

    Can you provide an updated link to download the guide please!

    Reply
  68. koanla

    Hi! I’ve got a faulty G27 and don’t know what causes the problem so that what should I do against.
    Hope that the experience gathered here could help solving the issue. The symptom: wheel started slowly but gradually losing its power. It means that when FFB reached a certain amount of force then it lost all force in all of a sudden, motors were “whining”. A realized that after a few cases that this happened only above a certain force only. If the FFB didn’t exceed that amount of force then it worked fine. Then I pushed the slider of the general force on logitech profiler back to about 70-75%. after some time it was exceeding the limit again so that I had to decrease the force lower and lower. Currently running on 30% and even sometimes (especially at fast wheel moves) I still feel and hear that it’s getting a bit much. Have took apart the whole thing, cleared the brushes, the commutators, etc. Resistance seems fine so I don’t know what causes the problem – whether motors or mainboard. Could any of you please help me in this? Not sure whether this is a known problem but I’m already facing it since several months,even year(s)…
    Thank you in advance!

    Reply
  69. Peter

    Thanks for this great thread, my G25 wheel has the same issues as described above. I’m going to clean the motors and replace the MOSFETs but mine seem different than the ones in your post? Instead of a IRF 7342 and 7103 I have a 9977GM and 4951GM. Are these identical or should I order different replacements? Here’s a picture of my PCB: https://imgur.com/WQRRymG

    Furthermore, the engine without the encoding wheel is measuring only 11 ohms and when I apply direct power to it from a 10V battery, the motor spins but starts to smoke. Just to be sure, I’ll clean out both motors and replace the MOSFETs, but the question is: with what do I replace them?

    Reply
    • John

      It looks to me like your wheel has uprated MOSFETS – they seem to have slightly better specs with higher voltage or current ratings. If you compare the data sheets of AP4951GM and IRF7342 they are very similar and I’d say interchangeable. There are many other versions that would work but the main thing is that they are Dual MOSFETs one chip is p-channel the other is n-channel. As long as the voltage and current ratings are same or slightly higher you should be fine.
      IRF7342 – 55V 3.4A
      AP4951 – 60V 3.4A

      How about: http://uk.farnell.com/diodes-inc/dmph6050ssd-13/mosfet-aec-q101-dual-pch-60v-soic/dp/2748300
      and: http://uk.farnell.com/infineon/irf7341pbf/mosfet-dual-nn-logic-so-8/dp/9102035

      Reply
      • Peter

        Thanks John. I’ll try replacing them with the MOSFETs I have lying around, otherwise I’ll try with the ones you posted.

        Reply
  70. Paul

    Hello,
    Could please someone help me?
    My g25 didnt calibrate, it was turning max do the right and stops. I found the encoder wheel was broken. Rapaired it, but it nothing helped at all. I realised mosfet 7103 was burned. I replaced it. But still nothing hapoens after pluging cable into 230v. The mofset were making itdelf really hot after oew sec. The wheel didnt turn.
    Engines have 32ohm both of them.
    I mentioned that f1 is broken. So i sodered a shitt cable to rapair it. I pluged the cable to power suply and after 2 sec both mofsets burn… i reolaced them. Replaced a fuse with 3,175a, and i am out of ideas what else could it be… oh i replaced one resistor 101ohm which was burned to…
    any ideas?

    Could someone measure and give a screen of the board turned on, with adnotations where should be what voltage (if – is on a – of the power supply, what measurements give + on each power board pin, diodes, ICs etc?

    It will be really helpfull for me…

    Is all the board powered with 24v or there is somewhere other voltages? In mine everywhere is 0 or 24v …

    Reply
    • John

      Hi Paul,
      Your wheel LEDs, buttons and switches should all work with just the USB cable connected and the 24V supply disconnected. I’m pretty sure the 24V is only present on the motor drive circuits: across the MOSFETs, the fuse, and the large diodes near the motor connectors and perhaps Q12 and Q13. The rest of the board is powered by the 5 or 12 volts on the USB cable. Read the full write up here https://drive.google.com/file/d/0By0qHn5uc92KRkRBTVYwZ1h4RGc/view which includes lots of trouble shooting tips.

      Reply
      • Paul

        Thanks for the reply. I have read this pdf many times from start to the end. I bought and soldered f7103 and 7342 from this tutorial, also replaced one resistor which was smoked and suposed to have 101ohm and had 67. Replaced the green fuse with removable 3,175A fuse. When i put minus of the multimeter to minus of power supply (24v) and stick the plus cable from the multimeter to any leg of the f7103 or 7342 there is everywhere 0v. But when i switch the cables (one to plus of the supply, and other to legs of f7103, 7342 there is almost everywhere 24v. Even on every cable which goes to pedals, shifter, usb, and even a optical encoder. The whole electronics in this wheel works on 24v?

        What else i could check to make my wheel live again? 🙁

        Reply
        • John Hunter

          Paul, does the LED on the gear shift light up when the USB cable is plugged in and the 24V power Supply is disconnected?

          Reply
  71. John Hunter

    Note that everything on the G25 can work without the 24v supply—except the steering calibration. And it has to successfully finish the calibration cycle (when it’s first turned on) in order to work as a steering wheel. All the other buttons and switches and LEDs can work with ONLY the USB cable attached. If the LED isn’t lit or Windows can’t see the device and switches working then check the USB cable or something – your problem isn’t the motors, MOSFETs or 24v supply.

    Actually if you could trick the wheel into calibrating by grabbing it and rotating left and right it as it usually does when you start up, then even the steering would work but without the force feedback of the motors of course.

    Reply
    • Paul

      John, i tested the wheel in many situations.
      1. Pluged only the wheel to power supply without pedals shifter and ps3 console. The wheel turns max to the right and stopped. Nothing more happens.
      2. Wheel plugged to shifter pedals and usb.
      Green diode is blinking on the shifter. Gears are working, pedals working but wheel dont turn on. Absolutly dead.
      The difference between the 1,2 that wheel is no longer turning to the right and stops is that i repaired the encoder wheel, and replaced burned mosfets. From that moment wheel doenst give any signs of life. 🙁

      Reply
      • John

        I don’t know Paul, a few of us had to replace the MOSFETs more than once because they are very sensitive to overheating with the soldering iron. I had this symptom myself, where the wheel goes one way and stops, before I replaced the second chip: IRF 7342

        Reply
        • Paul

          Can You tell me what voltage supose to be in g25 on the board where i did measurements ( i wrote about them few posts ago) and the parameteres of the diodes what suposed to be?

          Reply
          • John

            I don’t know Paul but my guess is the USB supplies up to 5v on the gate of the MOSFETs which in turn controls the 24v across the source and drain. There are two MOSFETs in each chip – I think one chip does clockwise movement and the other anticlockwise – and one MOSFET will do motor A while the other does motor B

  72. Paul

    Hello once more. Its been a while since my last post. I had a few hours of free time today. So i reolaced the mofsets for 3 time (both). I pluged the power supply, nothing happens. But when i plug the usb cable to pc, the wheel turns identically like on this video:
    https://youtu.be/UM1-fqv1ewk

    Any idea what could be wrong?

    Reply
    • John

      Hi Paul, I’d say the MOSFETs are now working since the wheel does actually move. It’s normal for the wheel to do nothing when the power is plugged in without the USB connected. So it’s trying to calibrate but maybe it’s not receiving the pulses from the encoder – is the encoder wheel loose on the shaft or dirty? Not sure how you can test it without an oscilloscope. Does the wheel turn freely through 900° when it’s unplugged – this will check that you have the gears properly aligned?

      Reply
  73. Zilahi Levente

    Hi!

    Thanks for your great tutorial, i find one of my MOSFET subtly exploded. I had a great luck finding the exact models in my country, so I ordered the parts, which were in about 2 days.

    Although my focus is on the motors that caused spike on the first place. I had problems with my non encoder motor before, i cleaned it, and put back, but it caused the death of the MOSFET now.

    When i tried to spin it by hand, it was clearly clogged, as i could easily rotate the working motor.

    Took apart, throughly cleaned it, put back together, now it’s better.
    What’s more, it’s now turning better than the untouched.

    But.
    It has some noise (like a bad bearing), while the good one has almost no sound while operating.
    I’m worried that if put back together, it will, on some point clog up completely, so I have to take it apart again, not to mention I don’t even know where to find replacement motors.

    I was thinking about a diode or fuse I could put into the circuit to prevent resistance lower than 28ohm.

    Is it possible?

    It could defend the MOSFET.

    What do you think?

    Reply
    • John

      I would test the motor by applying 24V directly from the power supply and making sure it runs okay. You could measure the current and compare it with the other motor to get an idea of whether it will be okay once attached to the circuit board and MOSFET.

      Reply
      • Zilahi Levente

        I tested them, both runs okay, but the repaired one is much noisier than the other one.

        Also, how to measure: while 24V is applied, or not?

        Reply
        • John

          I think you need a ammeter in series with the motor to measure the actual current while it’s running.

          But the motor should spin freely—as long as it is disconnected from anything—so I guess you need to find out what went wrong when you reassembled it?

          I seem to remember that the bronze bushes can get stuck in the wrong position and might need to be straightened up in line with the armature?

          Reply
  74. David

    Hello John,

    I have a G27 horror story.

    Yesterday, I decided to connect a pcie USB hub for my PC using a homemade molex cable connected onto the power supply (great idea, I know…). The hub caught fire when powering on my PC. I tought that it was the only damage done. Thus until this evening when I wanted to play Assetto Corsa Competizione. I realized that my driving wheel was dead (I guess it was plugged when the short occurred).

    I do have 24V at the PSU. I then proceeded to the next checks.
    I am now with my opened G27 on my knees trying to find out what might have burned. The PCB looks good (unlike the PCIE hub).

    With your experienced, what could be the first component to get harmed by a short through the USB connector and how could I check it?

    Thanks for keeping this post alive and by doing so, helping so many people.

    Reply
    • David

      Actually, I saw some marks of heating at the back of the USB connector. The pins are uneven because some have sunk slightly. The same with the capacitor. I guess some of the components down the line have been damaged.

      Reply
  75. eric

    hi john , logitech g25 problem here.. i cleaned the encoder motor then change the two mosfets , the wheel calibration goes only to the right.. i manage to complete the calibration by hand and i have force feedback only when i turn left in games, another thing .. i mesure voltage on ic 7103 and get 0 volt on pin 1 to 4 and 10 volt from 5 to 8 on the 7342 i get 24 volt on pin 1 , just can’t figure out where the 7103 did not get the voltage

    Reply
    • John

      Hi Eric, have you overheated the 7103 when soldering it? They are very sensitive to heat and I certainly made that mistake. I only had success when I was very careful to get the soldering done one pin at a time and just touching the tip of the iron as briefly as possible. It’s unusual on a PCB to have two chips alongside each other in different orientations – I don’t want to be patronising but it would be easy to place both chips the same way on the board!

      BTW After nearly five years, my wheel is still working great and I’m really enjoying Dirt Rally with it – so don’t give up.

      Reply
      • Eric

        hi , i have replace the 7103 two times now … i have test without the chip and nothing was moving… after the installation of the 7103 wheel turn to the right… is the 7342 left side? i have replace the 7342 two times still have a short on 7103 s1 side …. 24 volt not comming to pin s1 …..

        Reply
        • John

          Hey Eric, I don’t have a spare board to look at but did you read the PDF linked to above? Sergio refers to a couple of transistors that could blow and F1 on the board could be a fuse – it normally has zero resistance. Also there are several variants of the IRF 7342 – make sure you don’t have the D2 version. Can you trace on the board how the 24v should get to pin1? I’m not sure that pin1 on the 7342 isn’t connected to 0v and +24v comes through from the motor onto pins 7&8 — in other words the FET sinks the current to ground rather than supplying it.
          If that was the case you’d see 24v going to one side of the motor while the other side is connected to pins 7&8 on the 7342.

          Reply
  76. Ramy

    First of all … Thanks for this magnificent thread.
    As for my problem with G27 …. Well it’s dead… No matter how hard I tried.
    I think what I have is main chip problem and i need confirmation from you guys.
    First I noticed what seems to be liquid traces on the switch board (shifts limit switches) …. And cleaning wasn’t enough … Then found that the red wire in the big jack which connects to the main board broken (bad design if you ask me … The wires are solid and hard which increase the chance of breaking results from twisting all the time) anyway.. got it fixed with almost zero resistance and the other wire beside it was giving about 24ohm … Got that fixed too.
    Finally reached the main board to find supply 5v on c6&c7 … still no supply to the red wire in jack 10 …. so I tracked it back to Q6 with marking (N5) which I had trouble figuring out what it is …. But after many trials of substituting it with another failed I shorted Right and top points which finally got me 5v to all jacks…. And that’s it.
    Still no light … No movement … nothing. I found some other problems on the 24v rail and fixed them but as mentioned before the wheel should work even without the 24v.
    So that led me to suspect the main chip (72F651) to be exact.
    So what do you think ?

    Reply
  77. tIAGO

    Hi,

    This just happened to me aswell.
    I thought it was the motors and replaced them with spares from a local contact, but soon realized I was wrong.
    Just bought the IRF7342 and IRF7103, let’s see if I can manage to solder them in place.

    It’s amazing how my wheel managed to last so long, unfortunately after so many years of abuse something had to give.

    Reply
    • Tiago

      G25 back from the dead!
      Thank you for your putting this on the internet! Really helped out!

      Reply
  78. EWARD

    Hi, Mine just broke down, but i cleaned the motors before one time.

    I was abroad for 6 months so did not use it for a long time and it tried to turn, it did for a little bit, if only i had remembered to clean one of the motors. 3 ohms… Now im only worried because i still measure resistance in the mosfetts, which might indicate that they are not broken. And im not sure what else it could be. Im not sure if i should order new mosfets or not.

    Reply
    • John

      It may not be that straightforward to test the MOSFETs in situ – the trouble is they are connected to other components on the board that will affect your readings. In any case 3 ohms is never going to be good so I’d suggest cleaning the motor and crossing your fingers!

      Reply
      • EWARD

        Gladly the motors have been cleaned and are steady now, do you think its still worth it to order 2 new mosfetss for each side and try to solder them on, and then cross fingers no other components on the board have been fried.

        Reply
        • John

          I would order four MOSFETs – they are so easy to overheat with the soldering iron!

          My method is to get the old ones off and use flux paste to clean the area and leave a little blob of solder on each pad. Briefly touch one leg at a time to solder the chip in place and let it cool right down between legs.

          Good luck

          Reply
  79. JoeK1973

    Hi,

    I’m trying to repair my G25 but can’t open the motors – what motors are they? Mine say 3J154 28 adn 1060415 but that means nothing to me. I assume they’re Johnson motors but I can’t find which ones?

    Cheers

    Reply
    • John

      Welcome Joe, have a look in the guide linked to in the intro at the top of this page – it tells you on page 12.

      Reply
  80. Gary

    Hi John,
    Wondering if you can help. A relative staying has a G920 which had been used on an xbox only. Was plugged into a PC with Logitech Ghub installed. Wheel calibrated then a short time later the light above the xbox button went out and the PC now will not recognise the wheel. Tried on 2 different PC with the wheel not being detected at all.
    As is out of warranty pulled casing apart and power is reaching the main board. That is as good as my electronics knowledge goes. Nothing looks burnt out.

    The the wheel died I had attached it to a HP elitedesk G800 G2 SFF. It has 4x SUB ports at the front consisting 1x USB 2.0 powered, 1x USB 2.0, and 2x USB 3.0.
    It was plugged into the USB 2.0 powered port. Could this be the cause of the issue?

    Any help appreciated. The wheel looks brand new and seems a waste to bin it.,

    I know a site where I can get a replacement main board if needed.
    Thanks

    Reply
    • John

      I’ve got no experience of the G920 maybe somebody else can chime in? What I would say though is that the issue described here and blown MOSFET drivers on a G25 will not stop the wheel being recognised. So Windows will still see it as a controller and all the switches and pedals do what they should. So it sounds like the main board has failed. No USB port would overload or blow a device. BTW where can you get a mainboard?

      Reply
      • Gary

        Thanks for the quick reply. I thought I would ask as the wheels don’t seem to change much.
        On a site aliexpress.com search ‘Motherboard for Logitech Steering Wheel’ and they come up. States for G27 and G29. Also steering wheel circuit board will come up for G29.

        After a bit of searching on the net I found someone stating that G29 and G920 share the same motherboard but due to one being for xbox and the other for PS4 they have different firmware so cannot be swapped over. I find that unusual if they are the same part.

        Reply
  81. Snoopy

    Main Chip Overheat Problem.

    Hello there. I’m back after 5 years. Since this is the only thread that helped me out with my G25 mosfets problem (thank you again) i’ll post new problem here, maybe i can find some help and it will help out to others.
    So the problem is Main Chip overheating. My 1st G25 worked well for about five years, but today i noticed that main chip is unnormaly hot, thank god i had a little radiator installed on it “Just in case” because it didn’t fit on both mosfets after i soldered them a bit angled.
    The chop heats even out of race. Looks like some shortage somewhere or a bad wiring. So i Have installed another PCB ftom another G25 and noticed that its ok. Ran few laps on Kyoto. Main chip till cold, but the motors heated higher that on 1st PCB. 1PCB – Main chip heating all the time, mosfets and motors are normally warm even in race. 2PCB – Main chip is cold, mosfets and motors are heating faster and to higher temp. Also the FFB of 2nd PCB is slightly sharper (never noticed that before, when was repairing and testing both of them 5 years ago).

    Any ideas?

    Reply
  82. Paolo

    Hi!

    Thanks a lot for the translation from the spanish forum and for Your post.

    I have three Logitech G25. One of them had the optical 60 slot wheel broken.
    But after installing one made of metal and carefully reassembled the whole thing the steering wheel won’t calibrate, when plugging the usb port in it tries to calibrate for three times but fails every time.
    I can see the device within Windows 10, i can click the various buttons, but the steering wheel doesn’t work.
    After reading the guide I have checked the OHM on the two motor (29,3 – 29,6 i assume good value), the resistors near the mosfets, the mosfets appears OK and without problems.

    Using a lens on the optical encoder board I have discovered faulty electrical pads and some desoldered pad. It appear the entire board is not reliable.
    Before riscking to use one of the other two steering wheel optical encoder boards that i have my question is (finally, You may think): can you address me/help me find/buy/rebuild one of this boards, please?

    Thanks again for the support i have already received troughout this blog and for the future help.

    Paolo

    Reply
    • John

      Ciao Paolo! It sounds like (some) code pulses are getting through from the encoder because otherwise it would very quickly stop trying to calibrate. If you’ve had the wheel apart, one obvious thing to check is that you can rotate it 900° (or 2½ turns). The encoder board looks pretty simple, can you just re-inforce the broken circuit tracks with some copper wire and blobs of solder? And as long as the emitter and sensor can ‘see’ each other through the encoder slots it should work. Thanks for your kind comments, good luck and stay safe.

      Reply
      • paolo

        Ciao John! Grazie per avermi risposto velocemente! Thanks for answering so fast!

        Yes, I can rotate everything freely.

        The encoder board it is indeed really simple design and I have already tried to reinforce the soldering points with wires, but I am not a professional and something is wrong (maybe I have damaged something, or maybe the infrared is not working, I have bought this unit second hand).

        I must check what I have soldered having beside a working board. I am thinking of disassemble my main unit…or find a donor…

        Thanks again! Stay safe!

        A presto! See You soon!
        Paolo

        Reply
        • John

          Even though your wheel rotates freely please do check that it can do 900 degrees! It is possible to reassemble it and (while it feels okay) it won’t actually do a full 2.5 turns. It does sound like your problem.

          Reply
          • Paolo

            Hi again John
            I finally managed to obtain another wheel to use as spare parts. This one for sure has the optical encoder working.
            Following the guide you translated I have also replaced the brushes on the two motors, cleaned everything, reassembled everything and now the wheel is back to life. I had also bought ans successfully used a smd rework station for the desoldering of the two ic’s on the mainboard, but after checking using the guide, i didn’t desoldered them. I will try to desolder them on another mainboard I have lyng around (also this one is a spare part).
            So, thanks again
            Bye
            Paolo

  83. Fairuz

    Hi John,

    First of all, I wanted to thanks so much on the article – really helped me on repairing the unit.
    I have a question, while waiting for the mosfet to arrive at my door step (You are correct John, the IR7342 was indeed a pain in the arse to sourced), I’ve checked the surrounding components and found out that the big diode that bridges the two motors has no readings. While the other two diodes show 0.9V. I’m not a electrical expert, is the diode spoilt? and what are the diode code for replacement? there is no marking on the diode, so I have no clue what diode spec I should replace it with. thanks in advance John. [edited]

    Reply
    • John

      Hi Fairuz, thanks for your comments! I would think a 1N4001 would do the job – I don’t think the the spec is very important. When you test the diode, make sure to disconnect the motors from the board first otherwise you may get a false reading. Connect a meter and check the resistance of the diode with the test leads both ways round – it should be infinite one way and about 0 ohms the other.
      + —|<—
      —|<— +

      Reply
  84. Ignacio Lepe

    HI!, first of all, thanks for all the information, it’s the most complete thread i have seen in the whole internet about this topic.

    I’ve bought a second hand g920 and it just refuses to stay connected to the pc, it keeps disconnecting every 5-10 seconds. Also, it won’t finish calibration, instead of that it will just turn right and stay there.

    Yesterday i opened it, i saw two zener diodes that where fried, so i changed them (i think they are 7,5v). I connected the USB and it got hot really fast, so there’s surely a short circuit. Then i noticed the C19 piece, one near the USB connector in the main board, wish i think is a transistor, also gets hot. Probably this was one of the reasons those zener died.

    I don’t know why it’s getting short circuited, and i also don’t know if by changing that transistor it could get any better.

    Any help will surely be appreciated. Greetings from Chile!

    Reply
    • John

      Hi Ignacio, Is there any Zener Diodes, they look like ordinary diodes to me? The hot three legged component is Q1 – a transistor indeed. Check out this site: https://eletronicabr.com/forums/topic/238508-pedido-de-ajuda-identificar-transistor/ it looks like it may be: AO3407A Transistor P-MOSFET unipolar -30V -4.3A 1.4W SOT23-3. Your fault – where the motor jumps one way and stops – sounds a lot like when the encoder fails – is it loose or cracked? Does the board heat up if the motors are unplugged? Does the wheel show up in Windows Devices when there is no power, just USB? – all the pedals and switches should work even without the power supply connected.

      Reply
      • Ignacio Lepe

        Hi!, it’s been a long time but i managed to find that transistor and replace it. I disconnect everything but the usb port and it keeps getting hot, so there’s definitely a short. I’m guessing it could be the circuit right beside the diode around C10 or Z1, because it gets warm too even without any charge in it. Besides that everything looks right and cool. i’m running out of ideas 🙁

        Reply
  85. thest1g

    Hi All
    I have the same problem with my G25.
    I have cleaned the encoder motor and changed 7103 mosfet first. Result was that when I plugged wheel to the PC it started calibration went to one side and stopped there. My thinking was that when I change other mosfet it will work but now when I changed 7342 when I plug it in and connect power power LED on the shifter blinking about 10 times slow than it continues to flash little faster. No movement on the wheel. Power adapter gives 23.6V.

    Any ideas? Hope that someone is still reading this after all that time post was started…

    Reply
    • John

      Hi, I’m still here!
      Your experience sounds a lot like mine – I’d suggest you go through the all the comments above for clues. First I would check that the wheel does a full 720 degrees rotation – it is possible to reassemble it with the gears misplaced so that it doesn’t rotate fully. This may have been why it went one way and stopped. Now that you’ve changed the second MOSFET I suspect too much heat may have damaged both of them? They are very sensitive to over-heating with the soldering iron and it took me two attempts to make them work. Good luck.

      Reply
  86. John

    Just finished in 59th place after 12 months rallying in the Official Codemasters DiRT Rally 2 competition. Wheel still working well but I have had to fix/modify the paddles which were giving problems – the metal leaf springs were losing their springiness and so I glued a sheet of carbon fibre on them to stiffen them up. Unfortunately I wouldn’t know where to buy more of that though.

    Reply
    • Leonel Monti

      Comentar *Hello, first of all I want to congratulate you for creating this beautiful thread full of information that can help and guide so many people, then I want to describe my problem with a g27 that I bought second hand. The steering wheel was really cheap, they only wanted to change the encoder wheel for a metal one and used glue for it, ruining the infrared, I cleaned them, resoldered everything and left it aligned, the steering wheel worked GREAT without problems. Then I had problems with the centering, it would go out of calibration by itself, but it was also a problem coming from the encoder that I managed to solve again.

      Here is my problem: When assembling the board I had connected the USB and the 24v, surely it touched the metal and made a short circuit for some reason I did not realize it, having the entire steering wheel already assembled, I tested it, I noticed that it was not calibrated, I had to move a little for it to start calibrating and it did so very slowly as if the motors did not have the strength to move the entire mechanism, the calibration was completed very slowly but everything seemed to go from 10, when testing it with games, the strength response is very poor, the motors have no strength, they do not resist movement, replace one of the mosfets because I cannot get the other one since I am from Argentina and I cannot import them because it is very difficult to do it here and taxes are very high . Returning to the problem, I measured the resistance of the disconnected motors and they give between 28 and 30 as they should, they turn easily and are fine, I have no idea what it could be, I already measured resistances, transistors, all with correct values, I did not find the fuse since not the same board as the g25, similar but not the same. Does anyone have an idea what it could be or recommend me to do some extra measurement?
      Both mosfets are also measured with the method indicated by the thread, the one that changes was to see if something happened but they are both working, I understand. FROM ALREADY thank you very much for everything a huge greeting to all

      Reply
      • John

        Hi Leonel – thanks for your comments. How about checking the 24v on the power supply to make sure it’s correct even under load. But also check that there’s no AC component to it? You can also disengage the motors and put 24v directly onto each one to check that they spin fast both ways. If directly connecting the Power Supply seems to drive the motors well, then surely the PCB has a problem – probably the MOSFETs but maybe the signal to turn them on? I’m not sure how to test that.

        Reply
  87. casrya

    Hi All,

    I am pleased to report another success in repairing an old G25 by following the guide so wanted to add my thanks to the original authors for their useful info!

    Also, a couple of points in case it helpful:

    My fuse was blown and the mosfets were reading bad so I replaced the fuse and both mosfets as well as the two transistors for good measure.

    Make sure you measure the resistors with the mosfets removed since I had a few reading bad with the blown mosfets but they were ok after I removed the mosfets and added new ones so I did not need to replace any smd resistors.

    Same goes for the diodes, these can only be measured properly (using multi-meter diode test) when the mosfets are removed. Again the three of mine measured ok (but only with mosfets removed) but they appear to be Littelfuse PK6E series if anyone needs them.

    All of the parts are available cheap on AliExpress in quantities of 10 if you don’t have good local options and don’t mind waiting a month or so (Faster options like DigiKey are expensive in Australia, especially the delivery).

    https://www.aliexpress.com/item/1873840970.html
    https://www.aliexpress.com/item/32807410808.html
    https://www.aliexpress.com/item/1005001451891350.html

    SMD Chip removal alloy works well for removing the parts without damaging the traces, especially the mosfets https://www.youtube.com/watch?v=aqGuH6Tfw80

    Drag soldering with a fine chisel tip and plenty of flux paste (I used the tube from the chip removal alloy) works for re-soldering (if you don’t have a hot air pencil) and I was able to do it in one go without wasting any chips.

    The board will work with a single motor if you do not have a replacement and just want to get it working with reduced force feedback. From the description above it sounds like one mosfet is used to turn both motors in a specific direction? BTW can anybody confirm if this is the case or if a single mosfet controls one motor in both directions?

    I damaged one of my motors disassembling it (hint .. use heat such as a butane torch to remove gear .. don’t try to pull it off!) so got a secondhand replacement from ebay but it was actually wired the wrong way so not sure if this is because it had been disassembled (which it clearly had) and the wires connected the wrong way or if the left and right motors are wired reverse polarity? Anyway is something to watch out for and the symptom in this case is that the motors do not turn during calibration (other than a bit of clicking) since they are opposing each other and end up blowing a fuse (luckily I had spare fuses from the 10 ordered and was able to identify the problem quickly!). In this case the power led flashes continuously. I ended up just swapping the wires in the motor connector by lifting teh release tabs since this is easier than stripping the heatshrink and resoldering them.
    Anyway, in summary, thanks again and most of all I was pleased to keep the G25 out of landfill especially since in Australia the latest logitech replacements are $499 AUD retail and cheapest online at $399AUD!

    Regards,

    carya

    Reply
  88. Cozmo

    On a G25 I have replaced both Mosfets and the optical encoder wheel and serviced the motors. I switch it on and it goes left the right. I can see pulses with the scope on the encoder header. My problem is that axis zero ( linux ) is reported as zero. Is it possible i need to replace the LM393L ?

    Reply

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