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CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts list

Re: CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts

2012-03-26 by sasami@hotkey.net.au

>Hi,
>
>I have two CGS48 Rev1.0 VCOs that I started stuffing today. But when I got
>to the 1N4148 diodes I only found 10 on the PCB while there are 12 in the
parts list
>and schematic.
>
>Am I missing something?

It sounds like you are missing two places to put diodes!

I can only see 10 on the overlay myself, so I guess there is an error in the
parts list.

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/>

Re: CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts l

2012-03-26 by Ove Ridé

On 26 March 2012 19:32, Joachim <sonicwarrior@...> wrote:
Show quoted textHide quoted text
> Hi,
>
> I have two CGS48 Rev1.0 VCOs that I started stuffing today. But when I got
> to the 1N4148 diodes I only found 10 on the PCB while there are 12 in the parts list
> and schematic.
>
> Am I missing something?

When investigating the board schematic and board layout, the schematic
mentions 12 diodes whereas the board only has 10. The ones missing on
the board are the two diodes facing opposite directions, connecting to
pin 2 of the TL072 near the top of the schematic. Those are basically
overshoot protection as far as I can tell and not strictly necessary
as long as you don't have ridiculously high CV voltages.

--
/Ove

Blog: <http://blog.gg8.se/>

"Here is Evergreen City. Evergreen is the color of green forever."

Re: CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts l

2012-03-26 by sasami@hotkey.net.au

>When investigating the board schematic and board layout, the schematic
>mentions 12 diodes whereas the board only has 10. The ones missing on
>the board are the two diodes facing opposite directions, connecting to
>pin 2 of the TL072 near the top of the schematic. Those are basically
>overshoot protection as far as I can tell and not strictly necessary
>as long as you don't have ridiculously high CV voltages.

Ah, the clipper. Yes, that was removed a version or two ago.

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/>

Re: CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts

2012-03-26 by Kyle Stephens

Oop, speaking of errors, the 2.2K resistor in the schematic of the Peak section of the Peak and Trough circuit, the one between the base of the lower PNP and the input diodes, should be a 220K according to the PCB overlay and the original Serge schematic.

http://www.cgs.synth.net/modules/pic/pcb_cgs84_peakandtrough.gif
http://www.cgs.synth.net/modules/pic/schem_cgs84_peakandtrough.gif
http://www.cgs.synth.net/synth/serge/pic/schem_serge_r3.gif

I'm looking to build one of these with some higher voltage parts for my tube synth. Should be interesting alright... (rationale here is this is an easy way to 'mix down' signals without having to devote the current for several more tube heaters).


_Kyle
Show quoted textHide quoted text
--- On Mon, 3/26/12, sasami@... <sasami@...> wrote:


From: sasami@... <sasami@...>
Subject: Re: [cgs_synth] CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts list
To: cgs_synth@yahoogroups.com
Date: Monday, March 26, 2012, 2:51 PM







>Hi,
>
>I have two CGS48 Rev1.0 VCOs that I started stuffing today. But when I got
>to the 1N4148 diodes I only found 10 on the PCB while there are 12 in the
parts list
>and schematic.
>
>Am I missing something?

It sounds like you are missing two places to put diodes!

I can only see 10 on the overlay myself, so I guess there is an error in the
parts list.

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/>








[Non-text portions of this message have been removed]

Re: CGS48 VCO: Found only 10 diodes on the PCB vs. 12 in the parts l

2012-03-27 by Joachim

Big thanks to everyone for the answers. Now I can sleep well again. ;)

... and go on soldering the VCO.

Joachim

Am 27.03.2012 00:34, schrieb sasami@...:
Show quoted textHide quoted text
>
>> When investigating the board schematic and board layout, the schematic
>> mentions 12 diodes whereas the board only has 10. The ones missing on
>> the board are the two diodes facing opposite directions, connecting to
>> pin 2 of the TL072 near the top of the schematic. Those are basically
>> overshoot protection as far as I can tell and not strictly necessary
>> as long as you don't have ridiculously high CV voltages.
>
> Ah, the clipper. Yes, that was removed a version or two ago.
>
> 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/>
>
>
>
> ------------------------------------
>
> The CGS Modular Synth home page: http://www.cgs.synth.net/
> Yahoo! Groups Links
>
>
>
>

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