Today I am restoring a Chroma Polaris. One side of the panel board wasn’t working. Well that’s pretty common with these Chrome Polaris synthesizers. The boards are connected via FFC (Flat-Flex) cable and over time (over years actually) they begin to disintegrate. The plastic has softener in it which hardens and than break. But when they break the also break connection. This can easily happen due to transport.
I cutted the cable with scissors right after the last break and wipe off the green with some (!) acetone. Just use as little as possible since the acetone do not eat away the coating only but also the rest of the cable.
I then soldered two adapters to extend the cables and also make it more flexible. Everything worked just great, except the noise switch. When I hit that noise switch the chroma cpu crashed. I read on the internet that this could be a common issue after such panel cable break. Someone had written a new OS to fix that issue. I replaced the eproms with the latest OS version and voila. Both panel worked. No issues whatsoever.
I cleaned most rust, all faders, ouside and inside (o,c,c), reflowed some solder joints (cold solder), cleaned the pcbs. Last but not least there was some ADSR issues with some voices, which were gone after recalibrating the synth. Here is my repair story I share with you.