Sorry to bump up an old topic but...........
I recently did the compo mod on mine (its the one with the boards slotted on top and ill im getting is a very dark image thats rolling a bit, tried adjusting the POT and it just went blank.
Tried another cable/TV and another TV and I still get the same.
Nocited it has a resistor attached to the front part where the metal shielding was, tried it with and with out it connecting and still got nothing.
Any ideas?
I have pressed the two backwards arrow button and other games
Previously the only TV I managed to tune it into was a Black and white one