SNES video problems

[GiLL]

Recently posted this @ neo-geo.com and thought maybe the gang here could help.

I have a later model, larger SNES with video problems.

Initially it wouldn't power on so I replaced the fuse and now it powers up. However the video output changes between black and white and color both with sync issues. Kinda like when you have an RGB connection and you disconnect the sync line.

I have tried both composite and svideo with the same results. Same ac adapter and video cable work fine on a different snes.

So far I have:
Used different video cables (tested both composite and s-video)
Tested AC adapter on another machine (works fine there)
Replaced the fuse so the machines at least powers up
Tested the voltage regulator (outputs 5volts)

Thoughts on what might be causing this?

[l_oliveira]

Faulty video encoder. Have it tested on RGB.

[phreak97]

It could have a broken earth in the av port. Try an rf cable?