Out of the blue we got one of these recently. It was built into a very thick plywood flightcase which meant that cosmetically it was very good, and weighed nearly as much as a Jupiter 8. As it arrived it was not a synthesiser as nothing worked, and the reason was the usual ARP one of faulty sliders. The action of these was unsurprisingly awful, very stiff and jerky and not making anything resembling a good contact.
The obvious thing to do is to strip out all the sliders from the main PCB, dismantle, clean and carefully rebuild them, but this is a job that is fraught with difficulties. Getting the sliders off the circuit board cleanly is hard enough, due to the mechanical clamping mechanism that CTS designed into the system. Dismantling them is also tricky, as the means used to hold the two halves of the slider pot together is a crimping system that doesn’t repond well to being pried apart, and often breaks. We did out of necessity develop a technique of repairing this failing.
Then original grease used as the slider lubricant has turned to some kind of dark sticky sludge, and is partly responsible for the poor slider action, but dust and dirt under the skirt of the slider cap is to our mind the main culprit, as an experiment we tried to resurrect a dead slider by removing all contamination from the slider skirt to see if this was a viable possibility. It certainly improved the action of the slider but didn’t actually repair the fault.
To cut a long story short, we did strip and rebuild all of the sliders, they took half an hour each, and the synth worked perfectly after.
Do we want to do it again… We don’t think so… Please buy replacement sliders from anywhere else.
Or buy a Pro 1…