Hi,
Brand new here.
My sis is lookin at a 77 Polymoog. It’s in pretty decent shape, but the d3 button apparently does not work in some patches. If she buys it, she wants to send it to a synth guy my brother works with (we would ask him, but he’s on pto rn and can’t get a hold of him). So with this being the main issue with it, aside from just needing a general cleaning, how crazy of a job would fixing that d3 button be?
Hello
There is a FaceBook group called “Vintage Synth Repair”, you may want to post your question there. You’ll have to join the group, and some members are kinda cranky about free advice 
But others are nice.
Also, there are several vintage synth repair companies that you can find via a Google search. Some are more helpful than others.
Good luck with it!
Hey, yall. I’m new to this site. I’ve been dabbling with Moog synthesizers lately and been a big fan of the ones from the 70s. I’ve recently gotten th XILS PolyM and the Cherry Audio PolyMode. I was wondering, does anyone know/remember how to do sample & Hold Modulation that gives it that warbly spacey sound? I’m still figuring out the Polymoog since it’s so… complex. For such an old instrument with a thousands of variaties, I wanna learn it like I learn anything else.