Troubleshooting a broken Dreamcast

[bingobongo]

I have a Dreamcast that worked fine up until a few years ago - then it would freeze on the Dreamcast logo/boot screen. Today I finally installed a DreamPSU and, for a brief moment, I felt some hope as it booted beyond the logo (didn't freeze) and went to the date/set time screen. For a split second I also saw the game list menu appear on-screen, then no signal.

I tried rebooting, but it just kept losing signal. I left it on when I went downstairs to do something, and when I came back it was powered off - and wouldn't turn back on again. No signs of life. Tried a few more times, and the power light did light up for a split second, but only once. Now it's just lifeless. I'd be surprised if both PSUs were broken at this point? So it must be something on the motherboard?

Any pointers would be appreciated. I've done a small amount of soldering in the past.

[PengoJetz]

Could be bad or dirty connection on the PSU power pins on the motherboard, try cleaning them and check if need to bend them back into place to make a good solid connection. Could also be a problem with the GD drive connector not being properly aligned.

[bingobongo]

Could be bad or dirty connection on the PSU power pins on the motherboard; try cleaning them and check if need to bend them back into place to make a good solid connection. Could also be a problem with the GD drive connector not being properly aligned.

I had a look at the pins in more detail, and they seem fine. Nothing was bent out of place, no rust or any marks. I disconnected and reconnected the plugs going into the PSU, and it started up, but now everything is all yellow instead of that brilliant white?!! It also didn't stay powered on for more than about 10 seconds. Something is on its last pair of legs on the motherboard, but I have no idea what it could be?

I might just get a new motherboard at this point and scrap the one that's in there.

[PengoJetz]

You could also check if there might be issue with the cooling fan - if cable or connection has a problem or the fan isn’t properly cooling the board the sensor on VA1/2 models will tell the machine to shut down to prevent damage from overheating