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Cgs synth

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Re: SOLVED Re: Having a hell of a time with the VCS...

2010-01-25 by sasami@hotkey.net.au

>OK, the last problem turned out to be a cracked trace between pins 9 and 11
of the LM3900. Apparently, the force of cutting the lead alone cracked this
trace, so I'd like to ask Ken again if this might be a result of his new PCB
manufacturer, since I didn't have anything remotely like this problem with
other/earlier CGS PCBs.

I doubt it was the manufacturer. ALL boards suffer from this, with no
apparent rhyme or reason as to where and when it happens.

>Also, for the archive... if you can't get the VCS to cycle then setting it
in cycle mode and then adjusting the trimpot can help. The effect won't take
place immediately, but on the next power-up or trigger it should. My
procedure was:

A problem in the genuine Serge is that cycle locks up at various frequencies
due to a charge inbalance in the trigger circuit. I solved the problem by
changing the 10n capacitor to 1n . This is the cap near the cycle switch on
the circuit diagram. Perhaps you may consider making that change too.

Ken
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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