Could not get a stable signal for GBS-c

[stefz]

I just assembled a GBS-c to use with my Omega MSX computer, but I cannot get a stable signal. Check out this tiny video to see what I got:

https://www.youtube.com/watch?v=yHPygHI_KzE

I also tried to pass CV through a sync stripper circuit using a LM1881 to get a clean CSYNC signal. The results are pretty much the same using CV from Omega MSX or CSYNC.

[NoAffinity]

It seems this incompatibility is discussed elsewhere on the web. One suggestion is switching the output to interlaced mode, although I didn't see if this is confirmed to help.

[stefz]

It seems this incompatibility is discussed elsewhere on the web. One suggestion is switching the output to interlaced mode, although I didn't see if this is confirmed to help.

Thank you for answering. Actually I found the issue but I cannot understand why this happens.
I was using a 5V power supply for my MSX and another one for the GBS-c.
As both devices accepts 5V, I tried to connect them using the same power supply and it worked perfectly, nice and clean image.
Tried with other power supplies and it works as a charm – the issue happens only when I use two different power sources.

I think this might be something about basic electronics, like power lines, ground, etc – but it goes beyond my knowledge.
Does anybody can explain to me what could be happening?