Will Dreamcast start up with controller board disconnected

[noiseguy]

Picked up a Dreamcast V1 in very poor condition. On opening it found ribbon connector to controller board was missing. It doesn't boot up (no screen), drive inop) and wondering if I can rule that the motherboard is dead now, or need to wait until the replacement ribbon cable comes in to connect that for further testing.

Power supply voltages checked out, but unit had been previously pulled apart (missing screws, etc) and the motherboard was covering in residue... looks like tin fouling. I cleaned the motherboard with alcohol, hooked up power supply and drive, and powered up. Drive didn't spin, blank screen. Any thoughts appreciated.

[pcwzrd13]

No it won't. The controller board powers the fan and it won't turn on without the fan spinning.

[noiseguy]

Thanks; did some searching and couldn't find anything definitive. Guess I'll wait until the replacement ribbon gets here from HK before buying a replacement motherboard...

[noiseguy]

To give you an idea what the MB looked like on this. I think it's tin fouling. It looks better after alcohol wash and going over it with a Qtip but still not clean...

[noiseguy]

So following up: Managed to run down the correct ribbon cable and install. Light went on when power applied; as soon as I connected the AV cable and tried to repower the light flashed twice and went dead. Now won't power on at all. Not super surprising given what the insides looked like, so now on hunt for a replacement MB.

[noiseguy]

What are root cause for no video output?

Replaced motherboard with another VA1 board, connected power supply, controller board, fan, power switch, and GDEMU module with no SD card.
On power on, Power Light comes on, GDEMU light flashes, fan comes on, but no video output.
Remove GDEMU, reinstall CD ROM, on power on, power Light comes on, fan comes on, but no video output.

Anything this could be besides failed video out on motherboard?