Are any pins loose that the connectors plug into? Sure sounds like a cable issue. I have had a few of those. On my Congo, the old mpu died and replaced it with a Rottendog. Video was fine before but was messed up with new mpu. A new cable helped but still messed up. Tried another cable and it is much better. Getting new cables isn't expensive and nice to have spares if old ones still good. I also suggest actually testing all fuses. They can still look good when blown.