Thanks. I thought I might be able to use some of the resources I have. I've already ordered the new TLP521-1.

I think the optocouplers are faulty. I tested them like the diodes, but everything was fine. I was surprised to find that on the diode side, without the connector connected, there was a voltage of about 2V. The meter showed over 200k ohms between the diode and the transistor. This only applies to the optocouplers behind the CN3 connector. Let me know what you think. While I don't have the parts, can this optocoupler be replaced with another one?

Disconnecting CN3 had the same effect. I checked the optocouplers again and desoldered and checked IC28 – it's working. I'm still waiting for the new OKI and TD chips.

The optocouplers also seem fine to me. Maybe the TD62384AP chips? I ordered new ones and the M6253 converter on AliExpress.

The diodes have already been checked. I'll test the connectors when I have the opportunity

The steering wheel doesn't turn and there's no Driveboard Error message on the screen. There's no need to record a video. The game starts normally, just without FFB. The 74HC chips from step 5 have been replaced with new ones. Any other ideas?

After connecting the Drive Board to the game, it behaves the same as before. For comparison, here's a second video showing a working Driver Board. I'm testing it in Sega Rally 2 with the correct ROM, as Scud Race has other issues.

I'll make a video at the next opportunity. I noticed that the 7-segment displays don't light up at the same time. You can see it in the video. I've already checked all the elements from the guide and OKI. The ones on the back of the board are left.

 Er 20 is displayed on the 7-segment display.

Hi, I'm trying to fix the driver board. Thanks to the advice from this forum, I've managed to run 3. But I have a problem with one. Everything seems to be fine, but it doesn't work in the game. It doesn't show a drive board error, but ffb doesn't work and it's running at er 20. Any ideas what to do now? I can't upload video file to show you.