Update: Wurlitzer 200A–Still in pieces
I thought I would update on my hobby subject for tonight since I mostly worked on my Wurlitzer 200A electric piano instead of writing the post I meant to. I’m just now getting back into working on my electric piano after previously having zapped something on the board and not being able to get it working since. When I messed up last time I was actually trying to replace the capacitors and transistors that had dried up; I had thought these were causing considerable hum in the circuit. However, since deconstructing the piano I found a modification to the wiring scheme between the two speakers and the output headphone jack located at the bottom of the board. I found that on the headphone jack someone had wired in a simple RC circuit, presumably for filtering the headphone output. However, the small wiring scheme they used and meant to ground to the chassis had been disconnected, possibly by me. This floating output circuit could have been the problem all along! Only time will tell but I will feel silly if that was indeed the culprit.