You may have to superglue the two pieces back together when you’re done. If neither channel is working, the problem may be in the plug or jack. Wick up the old solder with desoldering braid for a ...
Everyone loves LED matrices, and even if you can’t find what you like commercially, it’s pretty easy to make just what you want. Need it big? No problem; just order a big PCB and some WS2812s.