[sdiy] bizarre Prophet 600 LFO AND SM's for obscure Crumar synths?

[Bob Weigel]

Has anyone seen schematics anywhere for Crumar Composer or Orchestrator 
2!  (It's similar to orchestrator 1 in that it has left and right hand 
sliders.  However it's totally different looking and has a polysynth 
section!  It's just before or after Trilogy I'd think from the look.  It 
may even be later... it's in new york with a friend and I haven't looked 
at the stuff inside yet.  It does have CEM3320, 3310's in it at least he 
said.  Hoping he'll get some pics inside to me soon.

Meanwhile I have a Composer with some strange issues.  It probably needs 
the M110 chip I'm thinking since the mono synth only works on the top 
half dozen notes less one as I recall when it works.  And it warms up 
and then goes into a long sustain mode..a warm up time somewhat 
inversely proportional to how many times you strike a key after turning 
it on.!

OK as if that isn't bizarre enough...ahem..I just fixed a Prophet 
600..had a bad LF357 dac I-V op amp.  However...it's mostly working save 
one thing near as I can tell.  LFO works great on PWM and FIlter 
modulation. But the pitch is all whacky.  Once you move the wheel or 
initial amount at all it immediately starts popping convulsive 
transients and more modulation than you'd expect at the low amount of 
modulation wheel you are giving it.   I'm thinking the EPROM is 
corrupted probably.  Any other thoughts on that one?

DOES ANYONE know how many of those were made?  This one looks like 
new..it's 5679 I think on the serial.  Highest number I've seen thus far 
I think. I have 512 in the studio that I just fixed finally (new 
contacts on some keys)  and when I went to put it together it failed!  
THe 74C02 that switches for 'power good' took a hit somehow.  Can't 
imagine how I did that... Took a while to figure that one out since I'd 
not had to do anything too in depth on those before.  Well we're up to 
speed now after the second one (number 25 something...) gave me the run 
around yesterday. lol.  Got it done about..5am... -Bob

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