Repair lifted ground pad on power amp
Here is how I would do this:


Unsolder everything and clean up all old solder.
Get a piece of copper foil tape, remove the adhesive with acetone, and cut it to size.
Put a small amount of solder (solder paste would work even better, but unless you do your own SMD work you probably wouldn't have any around, and it's fairly expensive stuff), and with the heaviest-duty soldering iron you have work over the top of the tape so the solder "filling" melts and attaches it to the old pads.


Drill holes and re-attach the old wires.
Post pictures if you succeed :)