Cgs synth

>Okay, so it's probably not those. I'm quite certain the speed & shape pots

are wired correctly.

Something is preventing them from oscillating. Whatever it is, that is what
you need to find. Make sure your 1N4148 diodes are in the right direction.
Also make sure that both power rails are getting to the chips.

>But I'm wondering, which part of the PCB is LFO1 and which is LFO2 ? Not

sure if that matters, but it's most likely that I've done the swap/join
switches not correctly. I've hooked up the top LFO's VARI pot pads ("top"
when Power pads are at the bottom) to the swap switch, and so on... Dunno if
this could influence the oscillation ?

Either can be LFO1 - depends on how you wire them. Usually I would consider
the one nearer the power connector to be LFO 1

>Or should I try to skip the switches as a test, and hook up the outputs &

pots directly ?

The switches and vari pots are the last of your worries - they don't affect
the core.

>
>_g
>
>
>--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>>
>> The first step would to be to find out why it is not oscillating, so
>> investigate the circuit around that area - and that means the speed pot and
>> the shape pot. Getting two wires to a pot swapped could well kill it.
>>
>> Ken
>>
>> >...more specifically the Utility LFO, to start with.
>> >
>> >Wired it up, with Join/Swap switches. +/-12V feed, banana jacks.
>> >LEDs don't flash, but a quick DVM measuring at the outputs gives me app.
>> -4V on most and even -8V on some other outputs (the Vari's, I think). The
>> output voltages don't seem to fluctuate at all... (I did not do an audio
>> check, nor do I have a scope)
>> >
>> >Apart from the obvious basic legwork (IC's put in correctly, no bad solder
>> joints, no short circuits at first sight, and that tricky little jumper is
>> present), what would be the methodology to start hunting for bugs ? Which
>> points should/could I measure first ? What would be good deductive steps to
>> undertake to pinpoint the problem ?
>> >
>> >
>> >tia !
>> >
>> >_guy
>> >
>> >
>> >
>> >
>> >------------------------------------
>> >
>> >The CGS Modular Synth home page: http://www.cgs.synth.net/
>> >Yahoo! Groups Links
>> >
>> >
>> >
>> >
>> _______________________________________________________________________
>> Ken Stone sasami@... otherunicorn@...
>> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
>> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>>
>
>
>
>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>

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