September 2014 update

I haven't posted anything in nearly two years, so I guess it's time for an update. On the vintage front, I've done a few more repairs and will endeavour to post details at some point. The current state of my synth collection is:

Roland Jupiter 6: All good. Previous repairs: Replace volume pot, resolder some front panel tact switches, clean all pots and sliders.

Roland Juno 106: Still dead. I haven't got around to removing the coating on the 8017As and will probably end up buying clones instead. Update: Clones purchased and installed 28/9/14. Now back in the living, but tact switches intermittent. Replacements ordered 01/10/14. Tact switches now replaced. All good.

Roland MKS 50: Works, but chorus clock bleeds into the output even when "off". Likely to be failing MN3101 BBD drivers. Still missing the top half of it's case - I doubt I'll ever find one. Update 29/9/14: Changing the 3101s had no effect. Probing with a scope reveals the BBD clock CV rises and falls in time with the noise. I now suspect a 4051 CMOS demux IC. 02/10/14: It wasn't the 4051, or associated TL072. Power rails noisy in the chorus area. 09/10/14: Recapping reduced the noise on the rails, but didn't solve the problem. Eventually found the sample/hold capacitor array CA1 to be cracked and missing it's common pin. Now repaired.

Roland MKS 30: A few temperamental tact switches, but otherwise OK. The 80017As haven't expired (yet). Update: Replacement EPROM and MIDI out mod installed 23/9/14. This makes the synth much more usable.

Roland U 220: No problems apart from a missing volume knob. Previously replaced a damaged mains lead.

Roland TR707: Perfect. Previously replaced power jack.

Oberheim DPX1: Perfect.

Yamaha TX81Z: No problems.

Yamaha DX7: No problems. Previously replaced damaged mains lead and  several broken keys.

Roland MC500: Working fine.

Roland SBX-80: Recently replaced tempo pot. Now good.

Roland SH1000: Working to the extent that it produces sound. All pots scratchy, keys intermittent and front panel severely rusted. No work done so far.

E-MU Emulator II: Finally working for the most part. The non-booting problem was cured by replacing a few ICs in the clock divider. Two RAM chips were also faulty, leading to corrupt samples, and two voices were silent. One was down to a faulty CMOS IC, but I have yet to diagnose the other. I have also cleaned all the switches and pots, replaced one floppy drive with an HxC floppy emulator and installed a new LCD backlight.

Yamaha QX3: New acquisition November 2014. Intermittent switches and encoder. Badly mangled case. Very dirty. Cleaned up and reassembled. Still much to do, but it mainly works.

I've spent the last few days replacing the batteries in most of the rack mounts. None of them were dead, but the CR2032 in the MKS50 had started to leak.