So anyway I mod N64s to RGB all the time and I keep running into this problem.
I have many parts to swap from so we can rule out the following:
RGB amp
Game Cart/connector
Jumper Pack
Roughly 1 in 15 consoles I sell have this issue and it is driving me up a wall.
Also these consoles work for some time and then something keeps going out on the customer's end
Also note that composite/s-video goes out as well.
I use the test point holes for the rgb connection.
I bend the shielding up so it doesn't pinch the wires.
Maybe the 5v is shorting somewhere ?
If anyone has any input it would be very much appreciated.