There are just a couple of large pins that connect the RCA jack with the sound board. Luckily there is plenty of space isolating any of the RCA jack terminals for the soldering. One of the terminals poking through the board was definitely loose from the RCA cable being hit. This is such a common problem and not my first time repairing such a thing. To fix this broken solder connection you simply apply flux to the broken solder and, if needed, add just a touch of fresh solder on top of it while the heat is being applied to the existing solder. With the flux the old and new solder should form quickly when the heat is applied. It only takes a few seconds and the connection should be even stronger than the original one.
The solder connection was covered with a drop of yellow flux and "re-floated" with just a bit more new solder. The older the electrical component - the more room and more success you will have with the larger circuitry. Reassemble the power and amp boards to the access panel and screw it all back together. All done, nice and easy.
