PC Steering wheel power issues

[Deivi_Z]

Hello everyone. So I got this PC steering wheel, Thrustmaster T500RS. And recently it started cutting out during gameplay. At first it was intermittent, now it's unusable. I've noticed that power adaptor light cuts out too but it starts working again when I unplug and wait for a minute or two. So naturally I thought that adaptor is failing. But before going for a new adaptor decided to do some googling maybe someone else had this issue. Found post with same issue, plus he noticed when he turns his wheel, power adaptor light turns on even if adaptor is disconnected from main power. He sorted his problem by getting new board from Thrustmaster support. I've noticed that my steering wheel does the same (video: https://youtu.be/-NCU9CslhAI). So my question would be , what internal part on PCB could cause power from motor being sent back to PSU?
What I've done:
Searched TM knowledge base, and found this:
Does the wheel shut down during gameplay? If the wheel is still shutting down during gameplay and the LED of the adapter turns off as well, then steer the wheel in big circles when this happens and check if the LED on the adapter has a flickering light.
If the power supply works fine by itself but when connected to the wheel it has this behavior, please contact us via phone or e-mail and we will further assist you with this matter.
I've wrote an email in hopes they could point me to right direction. Still waiting for response.
I disassembled wheel and tried checking mosfets (P120NF10). Desoldered and checked with multimeter, readings where fine. Noticed that mosfets where tinkered with before and one of them had different serial number from the others. I also checked diodes, but didn't remove it from the board, readings where also fine. Ended up ordering new mosfets, just in case.
Any input would be greatly appreciated. " alt="" class="bbc_img" />

[Manul]

Motor is driven by H-Bridge, so when it works as a generator it sends power back into the power rail through dedicated or internal mosfets' body diodes. Normally, I would not worry about that. On the other hand, there could be some additional circuitry to block it going all the way to power supply. If such a circuit exists, then it might be damaged. I would recommend to trace the main power rail. Does it go directly to H-Bridge?

If it does shutdown because of motor loading, I would try to replace power supply with something else, at least for testing. It might be power supply problem. Because as you say, it got worse with time. Bad electrolytic capacitors and control loop going mad? I guess it could also be motor itself, like shorting between windings, worn brushes (but I'm not motor expert).

Anyway, based on the fact that it was degrading slowly, the problem is likely to be the components which are aging, like electrolytic capacitors or motor. Semiconductor failure is usually catastrofic and permament. You should measure ESR of main capacitor for H-Bridge or just solder a new one and see if it makes a difference.

[Deivi_Z]

So thrustmaster responded (took a week). I was offered a new PCB for 70 euro. I of course agreed. In addition ordered new capacitor.  And will replace it with mosfests on old PCB once components arrive (delivery from china takes a while). Will report later if it helped in case someone else will be looking for info in the future.

[rasti]

Hi! Did you solve the problem by changing the caps and MOSFETs?

[Deivi_Z]

Hi, still waiting for mosfets.

[Deivi_Z]

Hi. So resoldering cap and mosfets didn't help. Acts the same

[T500RS]

Did you try replacing the main PCB that you ordered from Thrustmaster? Did it fix the problem? I think mine has the exact same problem, so would like to know whether to take the same route.

[Deivi_Z]

Yes. New PCB from Thrustmaster did help. Works good so far.