Copied Post – Repairs – More Info
Originally Posted: SUNDAY, 22 JULY 2012
Patrick Holder (at Teletech in Markham, ON) does it again! Alesis DMPro is repaired and so is my t.c. electronic M-One. Both had power supply problems.
The CS-40m, on the other hand, is still there. We spent some time testing the oscillator circuits on friday and it looks like the VCO chip isn’t quite working. It just isn’t quite scaling right any more. So now I need to find a Yamaha IG00153 chip. Hopefully someone has one somewhere. I saw one for around $100 but it might be an old listing.
This is the problem with old synths. They eventually break and if it’s one of the custom chips you might be in trouble. It’s not easy to find replacements these days since they haven’t been made in 30 years! I sure wish companies like Yamaha and Curtis Electromusic would do a run of 1000 of each of the chips these old synths need.
The OB-8 still needs to be examined. It has the exact same problem. Oscillator 1 on voices 5-8 aren’t scaling properly any more and as you switch the octaves (the keyboard transpose switches) upwards it goes further and further out of tune. In this case it can’t be the VCO chips because it would have to be all 4 on just that card. At least, I HOPE it’s not all 4!! It should be a controller issue. HOPEFULLY just a capacitor but it seems doubtful at this point.
The good news about the OB-8 is that the design was highly simplified so there isn’t a lot that can go wrong. As long as it’s not a custom chip or the computer, it should be easy to fix. At least, that’s what I’m telling myself!
So there you have it. If you’re thinking that it’d be cool to get an old analog synth, think again! You might only have it a few weeks before it dies and it could be very hard to fix! Get a new Minimoog Voyager instead. Or one of the new Tom Oberheim SEMs or one of the Dave Smith instruments. And then find yourself a synth tech or 2 because eventually you will need them!
In other news I made a cool discovery this weekend. I put the Yamaha CS-20m through the ElectroHarmonix v.256 vocoder and the sound was AWESOME. Very clear vocal sounds! Way better than the OB-8 sounds through it. And way better than the Korg M3 vocoder with the Radias. Awesome discovery I plan to make good use of … eventually.