Non-working System 11, Fantasy Club, Mushi/GaludaII advice?

[Kenchan]

Before I box these and forget about them forever, or give them away, I would love to try to get these following PCBs working:

Unknown NAMCO System 11 board: no picture, audio, anything. After reseating the satellite boards, get partial horizontal white on the screen.
TAITO G-Net: no picture, audio
Fantasy Club: honestly no idea what this is, no picture, audio
Mushihimesama/ESPGaluda II: LED comes on, but no picture, audio on either. No visible problems on one, the other might have a bad chip but I'm not sure yet

Any advice on possibly reviving these or finding out what's wrong with them? It's been suggested to increase the voltage for the SHIIIs, but I'm not sure. I've tried the boards in 3 cabs, and tried it powered from a PC supply. Many thanks in advance!

[mastercello]

You can always send the Cave games to Cave in Japan for repair - worth it i guess!

If you tried them in 3 different cabs i doubt it is a voltage issue.
But then have you measured the voltage with a multimeter?