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Serendipity Voice knob trouble

Started by insomniac2295, May 19, 2012, 09:16:51 PM

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insomniac2295

Directing this thread over to the Tech help forum now that I know what the voice knob actually does and that mine does not work. I've swapped out the pot, both tested pots function on their own, but don't appear to do anything in the circuit. The rest of the pedal is fine, I just don't get anything out of the voice knob. Could someone clue me in as to what might be causing the problem?

jkokura

If either R3 or C3 were an incorrect value or not properly soldered into place, that would be an instant and obvious issue. Other than that, We'd need some pictures and/or voltages to tell you. Mostly of the IC itself.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

insomniac2295

My meter is busted so, I'm going to try to do this manually. Just audio probed it and it seems the signal stops after C3. I shall replace C3?

insomniac2295

nevermind... screw it. i'm headed out to buy a new multimeter. i'll report back when i get some voltages

jkokura

After C3? No, there should be no sound there. That's VB.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

insomniac2295

Yeah, I realized that after my post  ::)
Anyways
*DC voltage at power supply: 9.47
*DC voltage at board in: 9.47

IC1 TL062-
1: 4.73
2: 4.74
3: 3.21
4: 0
5: 4.55
6: 4.74
7: 4.74
8: 9.47

Q1 2n7000-
S: 4.42
G: 4.73
D: 4.73

Q2 2n7000-
S: 4.58
G: 4.73
D: 4.73

All voltages checked and double checked.

jkokura

hmm...

Nothing looks wrong with your voltages. And you've triple checked the value of your pots?

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

insomniac2295


jkokura

And you've triple checked the value of your pots?

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

mgwhit

#9
Looks like you may have swapped a 3M3 for R1 and 100Ks for R6 & R7, but those shouldn't cause any problems.  (Apologies if I'm misreading the multiplier band on those -- looks orange to me.)

R3 and C3 look good.  Couldn't read R9 because it's standing, but that shouldn't really affect the Voice knob function.

If you can put up a better, less angled, photo of the board, I'd be happy to go over that.  Backlit would be even better.  Can't tell if there's a bridge to ground on your voice pot connection points or if that's a shadow.

frankie5fingers

+1 on the bridge at the voice pot.

insomniac2295

Solder bridge! That fixed it!!! I can't thank you all enough!!!  ;D ;D ;D ;D ;D ;D ;D ;D

irmcdermott

Quote from: insomniac2295 on May 21, 2012, 02:21:21 AM
Solder bridge! That fixed it!!! I can't thank you all enough!!!  ;D ;D ;D ;D ;D ;D ;D ;D

Glad you got it working!

insomniac2295

Another example of why it's always a good idea to get a second set of eyes.

mgwhit