Vintage Synth Repair

There are various things to check.

First of all, does any signal get to the S/H circuit at all - and does it
get through.

Check pin 3 of A2 (that's the input) and then pin 1 of A2 (that's the
output of the S/H mixer); of course make sure that the fader for at least
one of the S/H sources is up.

Alternatively you could also just check the "S/H Mixer" modulation routings
from the front panel.


This part verfiees that A2 actually works.

Next, check if signal enters A3 (pin 3) and if the trigger signal is there
(pin 5). I'm assuming the LFO works, right? Set the LFO to trigger the S/H
and check if there is the LFO signal at pin 5 of A3.


-- 
Malte Rogacki gacki@...
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"Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you
 get no sound out of it." (ARP 2600 Owner's Manual)
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