What TPG are you referring to?
Regarding the harness, you can tone out each ground and +5V line between the board and AR, to figure out which one(s) aren't making contact. Also, get or make an extraction tool, remove the +5V and ground pins from the connectors, clean them with acetone on a Q-tip, and gently bend the pins out to restore some of their tension, before you put them back in.
That's usually enough to take care of intermittent connections. Repinning the entire edge connector is overkill, unnecessary, and expensive, as most of the connections are low current, and don't wear out. It's only the high current power and ground pins that heat up and lose their tension over time.
Also, get a fiberglass scratch brush on ebay, and a can of DeOxit, and clean the fingers on the PCB edge connectors. Be sure to do both sides of both connectors. Burnish them with the brush till they're bright, wipe off the residue with Goof Off or 100% acetone on a Q-tip, then treat them with some DeOxit. That'll remove all corrosion, and make them like new.