My SNES worked fine without the OSSC and with my cheap Scaler last time I tried it, however, when I wanted to check it again a couple of minutes ago the PSU started buzzing and I didn’t dare turning the console on. Could a faulty PSU cause a problem like this?
I will also invest into a new RGB cable, the one I use for my SNES isn’t the best.
Update on the out of sync issue: played around with my Mega Drive
2X Mode: not recognized
3X Mode: out of sync
4X Mode: out of sync
However – Passthrough: No problem…weird.