Sounds like a poor internal connection. Anytime anyone says they "wiggle the _ to get it to work" it's a pretty good bet that the internal portion of that part needs some attention. Could be an AV port, a controller port, power port, etc. As systems age this is a pretty common issue.
If you know for a fact that the RGB worked fine at one time then investigating the area visually and reflowing fresh solder over all the component leads should work wonders