Corruptor not Corrupting

Started by Jamforthelamb, December 04, 2015, 12:01:07 PM

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Jamforthelamb

Hey All,
Recently built up a Corruptor PCB from Parasit, and I get a nice nasty cmos fuzz, but no ring mod'ing (if that's a word). The frequency pot and gate trim have no effect on the sound. I rechecked all my orientations (caps and diodes), checked my values, and reflowed all my soldering. I used a 4069UBE and a 4070BE from Tayda for the ICs. I've tried multiple 4069's with no change. Here's the
Schematic:


My voltages:

Source voltage: 9.4

IC 1 (4069UBE)
1: 6.4
2: 0.15
3: 3.99
4: 4.09
5: 4.17
6: 4.19
7: 0.00
8: 9.16
9: 0.07
10: 0.09
11: 8.38
12: 9.07
13: 0.00
14: 9.18

IC 2 (4070BE)
1: 0.00
2: 0.00
3: 0.00
4: 9.19
5: 0.15
6: 8.33
7: 0.00
8: 0.00
9: 0.00
10: 0.00
11: 0.00
12: 0.00
13: 0.00
14: 9.19

I've been in contact with Fredrik and here are his 4069 voltages from his build. Pin 1 and 2 are different then mine, but not sure if that matters:

01: 1,3
02: 8,37
03: 4,3
04: 1,3
05: 4,1
06: 4,1
07: 0
08: 8,39
09: 0,2
10: 0,2
11: 7,87
12: 8,38
13: 0
14: 8,41

Here's some build photos. One hole is open as Fredrik had me try lifting a diode to see if that made a difference, which it didn't.




You guys are my last hope before I just give up on this board. I see no reason why it shouldn't be working, but I need some new eyes as mine are getting tired =P.
Thanks
-Kevin

PRR

#1
I can not read the pin-numbers on that JPG.

Is the trim-pot even connected? If I squint the small image, I think I am seeing 9V where trim-pot has to be pulling-down to zero.

Can not tell if your joints are good, I can't see the leads for the blobs. I would beat half (all) that solder off, and re-solder so thin and fine you can *see* the leads and how the solder wets them.

The right-most panel-pot lead is clearly not "wetted" at the blob surface. Maybe there's a real connection inside; but I have seen similar joints "work" then fail, just light mechanical contact without any metal-joining.

And for some reason, trimpot legs seem to be exceptionally likely to be tarnished, refuse to take solder. Might sandpaper and pre-tin them.
  • SUPPORTER

Jamforthelamb

Hello!
Trim leg 3 does indeed have continuity with pin 13 of the 4069. The soldering is much better then what the photo indicates. I solder better then I take photos =p. Here's a bigger photo of the schemo:

blackieNYC

#3
Pins 4 and 1 should be the same voltage since they are wired together. Resolder there. Or possibly replace the chip

Edit- and if that works, you must try my blend mod described in reply #77 of his original thread.  Very simple. One 100k resistor and one 100kb pot. To dial back the RM so there is just a touch of it in the fuzz is a great option. Adds these little weird artifacts but doesnt sound like ring modulation very much at some settings
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Jamforthelamb

Cool man! Thanks for the tip. I'll definitely have to try that once I get this work again!
-Kevin