” I am the original owner of this Sequential Circuits Pro One vintage synthesizer, serial number 2064. I purchased it from Guitar Center Hollywood in August, 1981. The power transformer is case-mounted and the keyboard is the J-wire type. It has spent its entire life in my home recording studio and is in excellent condition as you can see in the photos.
If you’re not familiar with the Pro One, its sound generation is 100% analog. The keyboard inputs are digital as are its onboard sequencer and arpeggiator. It has versatile modulation routing and is outrageously fun to play with.
I did the following to prepare it for sale:
1. Cleaned it thoroughly inside and out.
2. Sprayed all the pots, slide switches and jacks with Deoxit, and verified that they operated smoothly and quietly.
3. Replaced the two rotary octave switches with new ones. The originals felt stiff and can’t be sprayed because they are sealed. The new switches are identical to the old ones.
4. Replaced the original power cord with a new one of the same ratings and length.
5. Replaced the two main power supply capacitors with new Nichicon 2200uF @50v audio equipment grade caps.
6. Cleaned the keyboard bus-bar and J-wires with tech grade (99.9%) isopropyl alcohol and cotton swabs.
7. Installed new keyboard bushings on all keys.
8. Leveled all the key tops.
9. Made some minor J-wire adjustments to even out key firing depth.
10. Tuned the oscillators and the amp balance circuit according to the procedures published by Sequential Circuits.
1. Everything in this synthesizer is original unless mentioned in the list above. It has never had any repairs prior to this and there haven’t been any cosmetic fixes of any kind.
2. There is a small (1/4″) hole drilled below the Audio Out jack on the back panel.This was intended to be used to bring out the digital interface that I never actually got around to implementing. The hole is plugged with a removable plastic plug that you can see in the pics.
3. There is a hairline crack in the volume wheel, which you can see in the pics. It doesn’t affect the functionality, but of course it is vulnerable. It can be opened wide enough to fill with glue, which I suspect would make it as strong as new, but I decided to leave any repair options to the next owner.
4. The bus-bar looks very good. There is some visible wear on some of the J-wires where they contact the bus-bar. Though it’s pretty easy to bend the J-wires so that a new surface is presented to the bus-bar, I again opted to leave all options open to the next owner, if it becomes necessary. As of now, all keys are firing consistently and cleanly.
All synthesizer functionality is working properly.” Link