As many suspected, it looks like the CBOX outputs a much higher voltage than it’s supposed to. I’ll post again when more information is learned, but for now know it is not safe to use this with SCART equipment!!!
@RetroRGB I tested that MVS from Aliexpress tonight, sync voltage is not spec. Vpp sitting at 1.6v pic.twitter.com/wilm0lUZr9
— Dan Kunz (@citrus3000psi) June 14, 2018
UPDATE (06/16): Dan was able to calculate that all that’s needed is a 620 Ohm resistor on the sync line and it’s safe to use with SCART equipment: