Loud Electronic Buzzing - Telecaster Thinline
I am trying to diagnose and fix a loud buzzing that occurs when using this Fender Telecaster AVII '72.
Whenever it's plugged in, it makes a noticeable buzzing sound until I touch some metal on the guitar (bridge, knob, pickup, switch, strings, or tuning pegs). It's not part of the signal chain, I have tested the setup with my strat and it's dead silent in position 2/4. Looking over the schematic and checking continuity with my multimeter, everything largely looks in order.
The big possible exception is the capacitor's connection to the volume pot. The capacitor is not jumped from the prong to the pot, but the pot, prong, and capacitor are all soldered to the back of the pot seemingly together (see: image 3).
Could that cause a grounding noise or are there any other ideas on what I could test out to find what might be causing this grounding noise? Any advice would be greatly appreciated.