I have a motherboard NUS-CPU-04 and found a couple things that I was wondering if anyone here could explain, as I don't know much about the N64's chips. I'm using a JRok RGB->Component converter.
I wired the RGB directly from the VDC-NUS-A (U4) to the multi-out pins like the guide says, but I couldn't get it to sync on the title screen of Mario 64 for some reason. The levels would sync ok, but when it switched to Mario's face or the logo it would just go nuts. Also, I had a dark picture like the guide warns.
So I cut the trace to the sync pin, and then worked my way backwards to see if something was messing with it. Anyway, I ended up on pin 5 of the ENC-NUS chip (U5), which all of sudden fixed all the sync problems when I went directly from the chip to the output. I can't find a pinout for this chip, but I know it encodes S-Video and composite video. I was under the impression that the older N64 units like mine outputted the correct sync to the pin on the multi-out, so I was wondering if anyone could shed some light on this for me. Is it my Jrok just not liking it? Something extra added along the way?
Also, I accidentally ground pin 23 of the VDC-NUS-A chip while looking for where to get the sync, and all of a sudden the picture brightened to normal levels. This is something I haven't seen mentioned in any of the RGB guides, so I was wondering if just leaving the pin grounded will eventually hurt anything?
Anyway, I was just curious, I've let the system run for a while and everything seems to be working great, but it'd be nice to know why what I did got it working, ha. Thanks!