Naomi Uni troubleshooting

[Benimaru]

Hey guys,

I'm nearly finished with my project now, fired it up the first time (literally!) now. Unfortunately there was an odour coming from the base, something like cooking plastic... It seems that the Naomi MoBo has some failure, because after unplugging it, everything seems to work fine on the first sight:

https://imageshack.us/i/pmXDLvNuj

Light box is running, speakers are making some sort of rustle and the monitor shows also signs of life, demag is functioning. However, even with my second Naomi MoBo I cant get a picture nor a sound running.
Someone have any toughts were to start with?

[RMRM]

Just plug both the Naomi motherboards to a PC monitor via VGA (getting power from the cabinet) to see if they are working or not. At least you can rule out mobo problems. You should also check (very important) all the voltages on the cabinet harness, power supply might be damaged too.

[Benimaru]

Thanks, have done like you suggested. Seems the MoBo is dead...
Fans are spinning and the LEDs are powered on, but there is not a single sign of life besides that. Is there a possibility to safe this one? Caps are all ok, can't detect anything broken.
However, everything else seems unharmed, the NOS Nanao 2932 shows finally shows a picture.

[RMRM]

Check if the CPU fans are both working (you have to take the case off). If this fan fails, the MOBO stops working and sometimes is just a faulty fan.

[Benimaru]

Checked both, PSU and the MoBo:
Second MoBo works with both PSU's, so I guess that can't be the problem.
Both fans of the probably faulty MoBo are spinning, but I can't get any signal out of it. The pcb looks also ok, no bursted caps.