SEM Help !

[Randy Alley]

AH folks ignore the following :
Hello to all on the synth-diy list ! I guess I qualify to participate 
since I'm too cheap to farm out work on my synths ;>}

Concerning my topic, I've got a 4-Voice needing TLC. I've got the SEM-1A 
Schematic, but no trouble-shooting instructions or component layout. 
(Unfortunately, I require such hand-holding when it comes to circuits. 
I'm a software guy by trade.) 
Do these exist ? How about the original SEM manual, any thing useful in that ?
If anyone could supply copies, I would happily pay expenses, and trade 
Memorymoog+ or ARP 2600 service docs if any one might need them.

I've got two SEMs a on the fritz:

One has a dead VCO1 and VCO2. On it I can't find a audio frequency signal 
anywhere. Proper supply voltages are present. Maybe I should suspect the 
CA3086 Transconductance Amp ? Where does the initial oscillationing 
signal first appear in the circuit ?

The other SEM has signals that I can trace to one side of the VCA section 
resistor R174, but nothing on the other. Seems like a dead resistor.

Please bear with me as I learn basic electronic trouble-shooting :>}

Any help or suggestions appreciated.

Sincerely,
Randy

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Randy Alley MSEE - Research Engineer
Research Triangle Institute - Center for Semiconductor Research
rga at es.rti.org
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