Yamaha QX3

I recently won an eBay auction for a "spares or repair" QX3 sequencer. It looked bad from the photos, but was very cheap. It turned out to be worse than expected. The case was held together with gaffer tape as and the PCBs were loose inside as almost all of the plastic screw posts had crumbled to nothing. It was also absolutely filthy, but a quick test showed it at least booted.

These used to be screw posts

The keyboard. Filthy and missing a few keycaps

Cherry key switches - and 30 years of crud!

I stripped the case of all electronics and gave it and the keycaps a bath and cleaned up the key frame and PCBs. Copious amounts of epoxy were used to attach new plastic standoffs to replace the broken screw posts. I managed to break one off on reassembally, but the rest seem solidly attached.

New screw posts glued in place

The floppy drive was full of dust, so this was cleaned up and reassembled, before being reinstalled.

Electronics cleaned up and reinstalled

Further testing has found that the sequencer basically works, including the floppy drive, but the encoder is jumpy and only works in one direction and a few of the keys are intermittent. I have removed, opened and cleaned the encoder and the worst of the key switches, but will probably end up doing every switch.

Still to do:

• Reinstall the encoder and check that it now works.
• Check the rest of the key switches and clean as required - or just do them all.
• Replace tact switches - these are the same as the ones in the Juno 106 and I still have about 70.
• Replace the mains flex.
• Replace missing key caps - I'm unlikely to find the correct ones.