Cgs synth

>When i measure the output of CPO it goes from 111mv to 201mv when the

button is pushed which is obviously not high enough to trigger anything.

>Any suggestions on what areas to check in the CPO circuit would be much

appreciated :0

A meter won't help because it only PULSES. The pulse is very short.
None the less:
All Type B boards that do not have a revision number have an error.
Physically between the two BC557s on the PCB is a 47k resistor. This should
be 470k, and will solve problems some of you are having with the common
pulse out.
I do not think you have that version of the board though. I expect you have
a ver1.1

AEP gives a pulse out every time the sequence moves, whatever the reason, be
it button, or clock or preset input.

Ken

>It was a big pain to swap these out after everything was mounted and wired

but i did it and now all the buttony-buttons work.

>
>Now to try to figure out why CPO and AEP doesnt work.
>I'll focus on CPO for now since i'm not really sure what AEP is supposed to

do. (i'll do some reading on this later once i have CPO working)

>I have gone through the schematic and traced all part values and everything

appears to be correct, but its also possible that ive missed something.

>When a button is pushed the A bus goes high to 6.20v and the stage selects

correctly.

>When i measure the output of CPO it goes from 111mv to 201mv when the

button is pushed which is obviously not high enough to trigger anything.

>Any suggestions on what areas to check in the CPO circuit would be much

appreciated :0

>
>
>
>--- In cgs_synth@yahoogroups.com, sasami@... wrote:
>>
>>
>> 47k, 150k, 470k, 820R 680R
>>
>> Cheers,
>> Ken
>>
>> Ken
>>
>> >> As i mentioned earlier in the thread this is the old style boards (non
>> RoHS), Just wondering at this point if there is a component value that might
>> be incorrect on all 8 stage boards.
>> >>
>> >
>> >okay, had an even closer look and i noticed that H was only going up to
>> 6.7v when pressing the button so i figured this might have something to do
>> with resistor values.
>> >I went back over the boards and i noticed a discrepency between the
>> silkscreen rev A and the picture of the rev b boards on the CGS site.
>> >The row of resistors closest to the LED and diode on my board are (in order
>> of closest to farthest (47k,47k,470k,820r,680r) and the CGS site with the
>> revB boards (47k,150k,470k,820r,680r)
>> >
>> >Now to further complicate things i was following the values listed on the
>> website, BUT i got the 47k and 150k REVERSED which probably explains the
>> voltage drop.
>> >My question here is, Which should i follow for these REV A (non RoHS)
>> boards. 47k, 47k, or 47k, 150k?
>> >
>> >
>> >
>> >
>> >------------------------------------
>> >
>> >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/>