From Michael E Caloroso Sent Sat, Mar 10th 2018, 01:31
From Michael E Caloroso Sent Sat, Mar 10th 2018, 01:31
I just restored a Memorymoog+ for a client as part as a gear trade for an Oberheim FVS + DS2a + Anvil cases. The Memorymoog was a basket case that I purchased from a friend, early serial number with the MIDI/Sequencer upgrade installed but lacking many factory service bulletin upgrades. In addition to the modifications that are in the AH archives I did a complete recap, complete new trimpots, cleaned up the very dodgy solder joints on the power harness and ground points, changed out the timing caps for the CEM3340s on the voice cards with silvered mica caps. There were many broken components including a 1458 that had blown and split open its case (!), fortunately only one bad CEM3340 and one bad CEM3360. The last mile to the finish line was the toughest... autotune wouldn't. Even though the display reads "6 TUNED" does NOT mean that it tuned the VCOs! After isolating many of the support ICs and confirming the audio path between the VCOs and autotune circuit the root problem turned out to be.... the Z80. EVEN THOUGH THE REST OF THE SYNTH FUNCTIONED. After going through final checkout, I have to say the tuning on this thing was SOLID. Those silvered mica caps make a BIG improvement in the tuning stability. While I was demonstrating to the new owner the concept of allowing the MM to warm up for at least fifteen minutes, I turned the MM on cold then played a chord... and it was IN TUNE before I even pushed autotune. I should get a trophy for that one. It's been almost a week now and haven't heard any complaints from the new owner. Yes, you CAN get a Memorymoog to stay in tune. Now I can start restoring that FVS... Sent from my iTrophyRoom, MC