I fixed the problem. I replaced all the caps on the power supply PCB and 1 of the film caps. (I was gonna do all the small film caps but I ordered the wrong size so I just went with the regular caps and 1 film cap.)
Ordered a $15 soldering kit on Amazon with a manual sucker and $29 worth of caps from digikey (I ordered extra just in case I messed up) so I realistically have about $30 in the fix. I replaced the old Chinese ones with higher quality Japanese caps.
It sounds better than it ever did and can shake the whole house if I want it to.