VCF test - scope shows no signal

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Pyjamas
 
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VCF test - scope shows no signal

Post by Pyjamas »

pins of the potentiometer: 0v 0v 3.3v 3.3v 3.3v 0v

please help me to identify the problem
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Pyjamas
 
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Re: VCF test - scope shows no signal

Post by Pyjamas »

anyone ? could i have burn the potentiometer ? there was some solder stuck in between first and second pin and when i was trying to get it out potentiometer was making some (rotating?) sound. did i burn it ?

all the parts seem to be in place and the Envelope test (next one) is showing good results.

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rv0
 
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Re: VCF test - scope shows no signal

Post by rv0 »

That picture is totally not usable for anything.

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Pyjamas
 
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Re: VCF test - scope shows no signal

Post by Pyjamas »

it's to specify which pin i call the left most

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antto
 
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Re: VCF test - scope shows no signal

Post by antto »

the picture is unusable
i will assume you're talking about the resonance pot
3 of the inner pins are connected to the accent, it looks like you got ~3V there, so that's okay
the other 3 pins are for the actual filter resonance, and it looks like you got 0V there, and surely you won't have any sound in the filter if the signal thru the reso pot (which is in the feedback path) is zero
maybe something is shorting to ground

i'd desolder the reso pot and:
1) check if the resonance pot is working properly - set it to 50% and check the resistance from pin2 (which should be the wiper) to pin 1 and 6.. you should get ~25kOhms if it works
2) check the voltage on the pin holes again, if you still got 0V on all of them - then there must be a short in the VCF somewhere. at least one of those pins should be biased to ~5.33V

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