via this auction
"This is an ARP PRO/DGX (Soloist/DGX) Model 2720. This synth has a low serial number of 2720 0385 and uses the more desirable 4034 filter. It's in pretty good overall condition, but it does need some work. It was stored in a dusty warehouse so it could use a thorough cleaning. It is missing: two slider knobs (sliders still work), one of the tilt screw feet from the bottom, some of the screws inside that hold the wooden sides on, and the sheet music rest back. We cleaned the key contacts and all of the notes sound. When I first powered it up all of the touch sensor features worked, but now I can only get the pitch and volume to work consistently. Some keys seem to trigger the aftertouch easier than others. I'm only capable of doing very rudimentary repairs, so I can't troubleshoot the cause. Portamento works great. Repeat works, but doesn't seem to work on all of the voices. Octave Transpose works, but the switch should be cleaned. The other issue that I noticed is, when you first power it on, all of the voices can be selected, but, after playing around with it for a little while, the first half of the voice buttons select sounds from the second half. (Meaning the "Bassoon" button will select "French Horn" instead)"
