My Philco type 732 started playing up after I had it as a daily driver for a few years. It emitted some disturbing electrical crackling. I took it to the shed this arvo and set it up on the dimbulb and off she went. All of a sudden a almighty crackle and flash behind the 6V6 . When I switched it off and had a real close look there was a pinhole in the dial lamp wires as they were going through the chassis ( a microscopic pinhole ) so I cut the wires and put some heatshrink on both wires and slipped them back into the chassis hole and wired them up again and wow my Philco is back. This with its Celestion speaker has a incredible sound. Yep the Kiwis got this one right.

Photo uploaded.

Thankyou Brad, I finally worked out how to attach photos from my phone. Its not as obvious as it is on a desktop.

Same issue with my STC 830 - five dial light wires go through a 1/4 inch hole. Had to ease it out a bit to fit some braided spaghetti. Shorts did not occur there though, but only a matter of time. Shorts occurred where the dial light terminals had rotated on the base and shorted against the earth terminal. Heat shrink was the fix.