I got bored yesterday (recovering from eye surgery) and decided to pull the gauge cluster to find out why a couple illumination bulbs were inop. OK, that was mistake #1.
I had it on the bench and decided to put 12 volts to each circuit to check which were inop (mistake#2).
The short version is I smoked 2 circuits on the circuit board. It took out the fuel gauge, illumination, and back fed the turn indicators. Good job. I spent the night looking for a used '74 cluster (we all know how well that went) and kicking myself in the butt.
I've done quite a bit of soldering as my dad was into electronics and had me doing it at an early age. I pulled the cluster again today and the copper was thick enough to take solder and make jumpers if done correctly.
Looks kinda ugly, but the bottom line is, yes, you can solder the PCB to repair screw ups and other assorted issues. Oh, and yes all my lights work now