Console dies shortly after boot logo

[node]

Hello! I'm trying to troubleshoot an odd Dreamcast issue. It rarely gets past the boot logo (although very occasionally it manages to show a second or two of game). The fan and power LED stay on, but the TV image goes blank. A slight electrical whine comes from the PSU as soon as this happens too, although I couldn't capture it on microphone. No blown out PSU caps visible.

I've got a GDEmu in it, replaced the fan with a quieter 5v one and removed the 12v as recommended when using a GDEmu. It was working with this setup for a number of weeks though, and GDMenu occasionally loads so that part is functioning.

Any suggestions for what to check would be appreciated, I've looked at various troubleshooting articles and videos but nothing jumps out specific to this issue.

[dav3dav3]

You may need to clean the pins on the motherboard with some isopropyl

[Xiden]

I recommend posting this on assemblergame dreamcast forum. Lots of dc troubleshooting helpers there

[Xerxes3rd]

Did you add that pull-up (or pull-down, I can't remember) resistor to the fan RPM line so that the DC is getting a proper fan signal? Some people alternatively use an Arduino for generating the PWM that the DC requires.

[dreamtrain]

The fan and power LED stay on, but the TV image goes blank. A slight electrical whine comes from the PSU as soon as this happens too, although I couldn't capture it on microphone. No blown out PSU caps visible.

From what you're saying here that would mean the fan is pulling too much current from the controller board. If you can disconnect the fans power and pull it directly from the PSU that should fix your problem.

I had the same issue with a controller that had a short in the connector. My dreamcast did exactly what yours did before it blew the controller resistor

[node]

Did you add that pull-up (or pull-down, I can't remember) resistor to the fan RPM line so that the DC is getting a proper fan signal? Some people alternatively use an Arduino for generating the PWM that the DC requires.

Thanks a lot for that suggestion, it lead me to do further digging and this post confirms that's what is needed!