At the risk of stating the bleeding obvious here, If opening this synth, be very mindful of the exposed mains wiring and fuses.
It's all too easy to brush a hand past it and get a shock.
One of the keys started to not sound properly. I opened up the synth, and removed the keys surrounding the dodgy one. The springs holding the black keys are different than those of the white so keep separate.
This synth uses carbon contacts with rubber tops and a quick clean with some switch cleaner and all was good.
I got another broken 3P in 2017
.Here is a video on how I fixed it.
The different sample and hold areas of the two main board versions.
In 2017, I also installed the Organix midi kit, from River technologies. It's fantastic. I can now use both the PG-200 and MIDI. I can also permanently set the MIDI channel to 3. Responds to CC commands. Well worth getting and easy to install
Late 2017 I though I had my second JX-3P fixed and then found no audio output. A dead BA662
I looked online and discovered that the BA6110 is almost identical in spec but has a different pinout on the first 4 pins.
I made a small adapter board so I can use the relatively inexpensive BA6110 instead of the £30 BA662
The pins are:
I found a current mirror circuit was not necessary for this application. It may be required for others though.
After some testing the 6110 works fine, with the pin swaps.