Alternator not charging + multiple meltdowns…HELP!!!

DANGER!! Bear in mind those two large ammeter wires ARE BOTH ALWAYS HOT!!! The RED comes direct from the battery through the fuse link, and the BLACK is hot via the ammeter and feeds to the "welded splice" and back out to the alternator

CLUSTER TROUBLES. There are several things you should consider doing now that you have the cluster out

1...Replace the original gauge regulator/ limiter with an RTE
2...Solder jumpers across the limiter socket on the PC board to the traces. Scrape them clean with an exacto, etc
3...The gauge studs typically get corroded. Work the nuts "loose / tight/ loose/ tight" a few times to "scrub" them clean and tighten
4...Check carefully the PC board to harness connector pins. Evidence of looseness, corrosion, you need to clean them up and solder them.
5...As you can see, "corrosion." Clean around all bulb sockets, clean the sockets or replace, and bend the socket contact tabs for better contact. Consider replacing bulbs. Some guys have "gone LED" but there can be complications.