So it turns out it wasn't the YM26600 chip after all - But an IC on the KAS board that was overlooked.. I ended up buying one, so now I have a spare. If anyone is looking for a Yamaha YM26600 I have one for sale in the UK. Tested and working. It will be going on eBay but thought I'd post here first....

Thanks Nooel, Yeah it was weird, I tested it in a cold place and played on it for about 30 minutes - everything was fine. I picked it up 2 days later and once I got it home it started going weird. I then left it on for a day or so and it played almost perfectly.. Then it just started going crazy. I ...

If you're gonna get it all restored, I'd also consider the Juno 66 mod.. It's awesome to have portamento/midi control/detune and unison on that synth. Turns it into a better machine without compromising the original features. As far as I'm aware the 6's don't suffer from the dodgy voice chips so muc...

I had a beautiful JP-4 which had the Midi I/O mod fitted to it. I thoroughly recommend getting that upgrade, as it replaces the original cpu and adds a ton of functions. Don't wire up the portamento though.. It changes the sound of it. I had a few issues with keys if I remember correctly. They can b...

Thanks for responding nooel. So the keys from D4 to the top of the keyboard, it triggers the notes as it should. When I change the octaves on the panel, the pitch changes accordingly. Anything below D4 plays the notes with a huge delay and overlap. Sounds like garbage. Many of the voices aren't actu...

Hello there. Did you get any further with this? I just recently bought a CS60 which is playing notes erratically, and only seems to be triggering notes from the very top octave. Whenever I press notes in the lower octaves, they either don't trigger, or trigger much later than when the key has been p...