Collosalus...it works? Wha, ok....

[Scruffie]

Very nice catch, wouldn't have guessed that was the issue but glad you spotted it.

[blearyeyes]

Everything lines up pretty much with the voltages in the build docs with the exception of ICs 3 & 4...the ones marked with an asterisk... Oh, I also replaced both opamps with no effect. The only thing is scruffies suggested swap of the two 15uF caps configured as a Bipolar cap in the LFO with 10uF and 33uF

voltages with 12.02v regulated power pulling 55ma {bench supply}

IC#1 ALL GOOD
7.37v
7.37v
7.37v
0 v
6.97v
7.38v
14.75v

IC#2 ALL GOOD
7.37v
7.37v
7.33v
0 v
7.37v
7.37v
7.37v
14.75v

IC#3  BAD ***
1.40v
7.49v
8.89v
0 v
7.58v
10.55v ***
14.76v


IC#4  BAD
1.217v **
2.218v **
1.375v **
0 v
7.34v
7.38v
7.39v
14.76v

IC#5 ALL GOOD
14.76v
7.37v
7.38v
7.38v
7.38v
7.38v
7.38v
0 v
7.38v
7.38v
7.38v
7.38v
100+ mv fluctuating
7.38v
7.38v
100+ mv fluctuating

IC#6 ALL GOOD
7.38v
7.38v
14.50v
0 v
7.38v
0 v
0 mv
14.75v
14.77v
10.87v
14.77v
14.77v
14.77v

IC#7 ALL GOOD
1.45v
6.07v
0 v
6.4mv
203.6mv
2.571v
1.447v
12v

IC#8 ALL GOOD
22v
0 v
14.77v

IC#9 ALL GOOD
14.77v
7.37v
7.79v
1.6v
0 v
7.37v
7.491v
7.481v

IC#7 charge pump is no longer getting hot after I fixed shorted 9v pad to 15v trace. the voltages above are new.. I have checked all caps and resistors for values but I have missed stuff before. I have searched for cold solder joints and bridges. I have re-flowed any suspect joints. This one has been difficult.  When I set the Bias I can hear the effect kick in but the sweep is not oscillating. When changing any of the controls or the trimmers the effect is obvious on the guitar signal.




Any help is appreciated.

[Scruffie]

That's getting very close so your audio path is all fine, power is fine, your clock is fine, it's your LFO not kicking in and seeing as the half the opamp of the width control that is in the audio path is fine and the other half isn't, we can pin point it down to anything following the 4013.

So IC4A (not B) & IC3 are the most suspect.

All the values in that section checked? Transistors all confirmed against the datasheets (for the particular brand) to be orientated correctly? Hopefully no more bad traces...

[blearyeyes]

Will do, thanks.

[blearyeyes]

I'm getting 13+ volts from pin one and three on the Sweep pot.. Trying to stare at the circuit board to figure out how that could happen. Pin one looks like it is to ground although the schematic is not clear. I used a standard pot instead of a reverse taper (C)  and wired it backwards... I'm not getting that voltage from other ground sources...


Sent from my iPad using Tapatalk

[Scruffie]

I'm getting 13+ volts from pin one and three on the Sweep pot.. Trying to stare at the circuit board to figure out how that could happen. Pin one looks like it is to ground although the schematic is not clear. I used a standard pot instead of a reverse taper (C)  and wired it backwards... I'm not getting that voltage from other ground sources...


Sent from my iPad using Tapatalk

Pin 1 of the sweep pot is not grounded, just floating, unless you meant the manual pot?

Just in case though, check that the power trace running next to pin 1 of the sweep pot isn't connected to it.

After that, check your values for R26 & 47 and then if they're right it might be worth pulling out IC3 and seeing if the voltages on IC4 pins 1, 2 & 3 stabilize.

[blearyeyes]

Well if pin one is floating then I'll just remove the wire from the pad to the pot. If that works then the trace is connected to the pad.. If not then onward!

So you can have a pad just floating and use it for component support. Who woulda thunk?


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[blearyeyes]

OK here's my guess:

Either pin 1 of the sweep pot is connected to the 15v trace or the positive pad of C13 is connected to the 15v trace as they both lead to to pin 6 of IC3b where the 10+v reading is where it shouldn't be...  When I get home the truth will be revealed! At least I freakin hope so!!!

My brain hurts... How do Beans function at this level without going Mad?

[blearyeyes]

Removed wire from Pin 1 on SWEEP Pot no change. Checked C13 pad and found no connection. checked R26 & R47 both 470k. Pulled IC#3 and IC#4's voltages did not stabilize; Still 2.2v on 1,2,3 and 0 on pin 4.
IC#3 pin 6 = 10.55v.

SWEEP POT Pin1 Disconnected shows floating at the pad. on the Pot shows 13.33v CCW and 14.08 Fully CW
SWEEP POT Pin2 Shows 14.02v fully counter clockwise and 14.08 fully clockwise
SWEEP Pot Pin3 Shows 14.02v fully counter clockwise and 8.84v fully clockwise.

Is that correct?


Going to re-check all values in area after cd1430.
Once again any help is appreciated......

[blearyeyes]

I'll have to come back to this one... Collosalus has kicked my butt....

[Scruffie]

You said you got 2,2V on pins 1,2&3 with IC3 out, that's fine so let's just focus on IC3 as the culprit.

I think... I would just try replacing IC3 with another OpAmp, just to be sure it's not bad, obviously check all your values in that LFO area though, make sure the electros are orientated correctly and reflow the joints too and that there's no shorts or solder hairs.

Think you're almost there

[blearyeyes]

Did all of the above, replaced IC 3, checked values, cap polarity, went over soldering top and bottom re flowed and checked with continuity checker adjacent pads and pads to ground just because. LFO still not ocillating.

Really has a great sound when I mess with the trimmers! 
It's got to be right in front of my face!

Sorry this is taking so long... I really appreciate the support!

Dan.

[Scruffie]

If you lift the pin of the width pot coming from the LFO then you have it isolated which might help you debug it.

What IC are you using? A 4558? Might be worth trying a 1458.

[blearyeyes]

@12.00v

After lifting pin 2 on width control, IC4a pins 1,2,3,4, are showing higher voltages
of 5.1v 4.9v 4.71v and 0v

IC3 is 1.4v  7.49v  8.9v 0v    7.58v  12.92v  7.37v  14.76v

=================================
Oh and previously IC4 was showing 2.22v on 1,2,3 with IC3 in or out (no change)

[Scruffie]

Lift pin 3 of the width, then check all the LFO traces to make sure there are no more traces joining that shouldn't, also did you try a 1458 (or LM358/TL022) for IC3? Then reflow all the joints in the LFO area, triple check all the values (R20-25 & C12-14) then cry  if it still doesn't work