I have bought two cheap THS7374 mods at ebay to install on my SNES mini and my N64 NUS-CPU-04, and i wanted to use the same CSYNC cable for both systems.
At first i installed the mod in the SNES mini and everything worked fine. Next i tried to install the mod in the N64, but i got no sync in the OSSC.
After talking to the cable manufacturer it asked me to short a jumper inside the cable to test. With that i got sync on the N64 AND in the SNES. But the question is, im not sure what that does, could i be damaging my equipment if i continue using then like this? I guess the default cable that worked on the SNES should be working with the N64…
Im a huge n00b at electronics and modding, so im reaching out here for help. Im posting the two mods pictures, the SCART cable with the jumper and the N64 install picture (which i followed from Voultar’s youtube video).
mods:


scart cable with the jumper (JP2) NOT shorted (this way i doesnt work with the N64):


n64:
