[sdiy] ADSR circuit trouble

[Simon Brouwer]

If the gate led is lit up all the time, then is the voltage on pin 11 of
U103 about 13.5V? If not, there could be a short between pin 13 and 14.
Also check if the power to U103 is OK. The digital and the analog ground
should be connected together, e.g. using link LK1 in the power supply
section.
If the voltage on that pin is 13.5V, check the voltage pin 2 U402. It
should be about 2V. If not, check R403. If yes, check the voltage on pin
3. It should be close to 0V. If not, check R401. If it is the same voltage
as pin 2, also check if there is a short between pin 2 and pin 3.

Hope this helps,

Dan Snazelle schreef:
>
> ok
> scratch that
>
> sometimes it shows zero
>
> other times it shows 7.
>
> when i was testing with my voltmeter and i touched pin 5 of the tl082
> (output opamp) the voltage suddenly dropped to zero. it then only came
> back when i touched underneath the board
>
> very strange
>
> but no matter what, that LED is lit up
>
>
> this is very confusing!
>
>
> thanks
>
> --------------------------------------------
> check out various dan music at:
>
> http://www.myspace.com/lossnyc
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
>
>
>
>
> Date: Fri, 21 Nov 2008 09:56:16 -0500
> From: beansharicots at gmail.com
> To: subjectivity at hotmail.com
> Subject: Re: [sdiy] ADSR circuit trouble
> CC: synth-diy at dropmix.xs4all.nl
>
> I built one of these a month or so ago (Metalbox version).  What voltage
> are you seeing on the output?
>
> -=john
>
> 2008/11/21 Dan Snazelle
>
>
>
> Sorry for all the questions guys. i will try to ask fewer after this one.
> this is the last NON working thing in my project.
>
>
>
> Here is a case of something that worked fine a week ago, and then when i
> wired it permanently, it stopped working.
>
>
>
> the circuit is here:
>
>
>
> http://www.elby-designs.com/asm-2/adsr/adsr1-asm2-cct.pdf
>
>
>
> and docs
>
> http://www.elby-designs.com/asm-2/adsr/adsr-asm2-about.htm
>
> (i built ADSR1)
>
>
>
>
>
> Oddly, The LED is lighting up constantly (not turning on and off)
>
> There is nothing on the ADSR output.
>
> The schematic is a loop so i am having a hard time figuring out where to
> check
>
> i have re soldered all the joints and changed all the chips (except the
> 4053 which i dont have another one ;(
>
>
>
> all the chips seems to be getting the correct voltage.
>
>
>
> basically i am stuck
>
>
>
> i have spent 2 days trying to look for solder bridges or incorrectly wired
> pots.
>
>
>
> i have hit a wall where my experience stops as i have only built one other
> ADSR (ray wilsons)
>
>
>
> there is nothing on pin 15 of the 4053 but all the other outputs of the
> 4053 are working properly.
>
>
>
>
>
> i am trying to figure out what might be a likely problem.
>
>
>
> obviously if the LED is always on, something is wrong
>
> ANY Advice would be great
>
>
>
> i have been testing it by sending a gate out (from a sample and hold) into
> the gate in.
>
> i am then taking the ADSR out and putting that into an external VCA (just
> for testing)
>
>
>
> i have started writing down all the voltages on each pot and pin if that
> will help anyone.
>
>
>
> thanks
>
>
>
>
>
>
>
>
>
>
>
> --------------------------------------------
>
> check out various dan music at:
>
>
>
> http://www.myspace.com/lossnyc
>
>
>
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
>
>
>
> http://www.indie911.com/dan-snazelle
>
> (or for techno) http://www.myspace.com/snazelle
>
>
>
>
>
>
>
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>
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>
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>
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>
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>


-- 
Vriendelijke groet,

Simon Brouwer
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