I have a similar problem.
Parameter and edit buttons do not work. Also the write button.
I can't get the write and tape enable buttons to enact parameter mode.
Voltages are all ok.
I would like to know if perhaps this might be a circuit, or even a connector (pulse) issue. The schematic that I found online is not clear enough for me to follow.
Background: when i acquired this Poly 61 it had a battery leak, so I replaced the Nicad battery to a Nimh and fixed the traces as best I could (following an unclear schematic). Currently the Poly will play a bunch of presets very well, the sound is good, but I would like to be able to edit the presets to create my own.
Any assistance would be most appreciated.Waz in Perth, Western Australia.