signal stops at q12 (non ladyada)

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evostars
 
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signal stops at q12 (non ladyada)

Post by evostars »

I traced the signal to q12 (vcf 2sc1583) and there it stops. It only goes to q11 and there it ends.
Q12 reads. 5 9 5 9 5 volts roughly. It enters from r70 on pin 1 and is on pin 3( middle) to the middle pin of q11.

I had a 2sc2291 in q21 by mistake. I now got the right part in it, 2sc1583.
Could this have broken something?

It says rollin-moss on the print, anyone know this one?

Any help is much appreciated!

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antto
 
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Re: signal stops at q12 (non ladyada)

Post by antto »

i think that's ModeMachines / TT

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

antto wrote:i think that's ModeMachines / TT
ohohw :cry:
that explains a lot...
I think there is also no program flashed (no leds...)

still, I need to fixe the VCF. Need to hear the vco at least...

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aminoacid
 
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Re: signal stops at q12 (non ladyada)

Post by aminoacid »

hi evo!


have you buildt the whole synth?


did you test the vco like the adafruit guide says?


do you have osciloscope to test with?

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

aminoacid wrote:hi evo!


have you buildt the whole synth?


did you test the vco like the adafruit guide says?


do you have osciloscope to test with?
Yes build it completly and checked it.
Did test the VCO like the guide, and its OK.
And yes I have a scope.
It doesn't show the signal after q12 :(
I'm going to check voltages in the VCF section tonight.
Got tips?

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mmm
 
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Re: signal stops at q12 (non ladyada)

Post by mmm »

What's the code for the 2SC2291?

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

MMM wrote:What's the code for the 2SC2291?
the code?
on the transistor? I'll check

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

evostars wrote:
MMM wrote:What's the code for the 2SC2291?
the code?
on the transistor? I'll check
I got it from x0xshop.de
should be original mitshubishi

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aminoacid
 
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Re: signal stops at q12 (non ladyada)

Post by aminoacid »

i would guess there should be signals all over in the vcf but for sure on the output transistor q19.

could be good idea to check q12.

you could switch q12 with q21 and see if signals appear further on in the vcf.

sockets are good friends when working with double trannies!

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

aminoacid wrote:i would guess there should be signals all over in the vcf but for sure on the output transistor q19.

could be good idea to check q12.

you could switch q12 with q21 and see if signals appear further on in the vcf.

sockets are good friends when working with double trannies!
Sockets! I'll put them in!

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substyler
 
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Re: signal stops at q12 (non ladyada)

Post by substyler »

evostars wrote:
evostars wrote:
MMM wrote:What's the code for the 2SC2291?
the code?
on the transistor? I'll check
I got it from x0xshop.de
should be original mitshubishi
the 2291 i have send to you is working 8)
i know it because i have no non-working 2291 transistors in stock :mrgreen:

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

SubStyler wrote:the 2291 i have send to you is working 8)
i know it because i have no non-working 2291 transistors in stock :mrgreen:
I trust you substyler!
I have a spare one now, if you ever need it, let me know :-)

evostars
 
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Re: signal stops at q12 (non ladyada)

Post by evostars »

I found that r108 in the VCF was 22k instead of 2.2k. This messed up the voltages in q21 and q19.
When i looked in the bag of 2.2k i noticed the same colors.
The whole bag of 2.2k contains 22k!!!
So only 13 resistors to check... And maybe replace...

Luckily for me there is a paper in the bag with the other resistor numbers...
Pfew. Feeling a bit more lucky (after firmware load failed)

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