synthgeek's blog

The pots I was waiting for were in the mail today, so I did the first round of mods. These mods are all documented elsewhere, so I won’t bother repeating all the info here. I just did the noise level & “Moog slayer” mods for now.

Here’s a shot of the main board with the trim pots for the filter cutoff & resonance and noise level removed:

Here’s shots of the new knobs (filter, then noise level):

One hint which I don’t remember seeing online elsewhere is that you want to use a reverse-action knob for the noise level.

Next I’m going to replace two trim pots on the delay board with front-panel knobs:

The knobs will go to the right of the noise level knob, in the middle of the two blank spaces, like the noise knob.

My Poly-800 MkII has developed a problem where the noise source is always on at full volume. Neither the envelope or volume parameter has any effect. The envelope still works on the filter.

I’ve got it pulled apart to see what I can do, if anything (will probably require replacing a chip I’m thinking, not sure)- and while I’m in there I’ll probably do some mods too, starting with the moog slayer mod. I’ll be posting pics as I go. The first set of pics are the innards before any poking around (other than some air dusting/vacuuming- it was pretty dirty in there):

main board 1

delay board

delay board- no flash

long view

main board above

The project may take awhile, since I’m not sure how easy it will be to find replacement parts. If it requires buying another Poly to cannibalize, then it will definitely be awhile before the repair gets done. However, the parts for the mods are easy to come by & cheap, so that may get done first.

Saw this posted at Matrixsynth, so awesome I had to repost: