If you have a function generator, even a cheap one, you could try to see if there is a break in continuity on the path somewhere between the composite video out pin on the AV chip to the multiout. That could tell you if there is an open component or broken trace. Be careful not to put any voltage on any pin above it's maximum rated input. check datasheets.splits wrote:I don't have one with enough bandwidth to see composite video signals, unfortunately. Maybe I should think about getting one...vol.2 wrote:If you have an oscilloscope, you could put it in video mode and trace the path back to see what's what. If you don't, I'm not sure what you could do.
Also, go back and check continuity on all of your solder joints, especially the ribbon cables. They look good visually, but you never know.