Moonwalker no video but plays with sound

[dennisN]

Hello, I have a moonwalker pcb hooked up to a sony pvm 20m2mdu via a minigun which just stopped displaying video. This is an original board with encrypted roms but with a desuicided CPU. The weird thing is I was playing earlier today and it was working fine, then it just stopped outputting video. Any help in trouble-shooting is appreciated!

I have already checked that video ground is connected to ground and the voltages are fine.

 

[SB_Electronics]

Are you getting voltages on the RGB lines? Has it been recapped in the past?

 

[dennisN]

Has never been capped. Let me check the voltages. Would a bad cap affect those voltages?

 

[SB_Electronics]

Potentially. There are no direct caps on the RGB lines on the main board but a faulty decoupling cap could stop one of the IC from working. Checking the voltages on the RGBS lines can help rule out faulty supergun, faulty SYNC or no video whatsoever. Do you get sound?