Dynacomp w/clean blend vero problem

[ibodog]

I made a vero layout using R.G.'s schematic, Jack Orman's schematic, and Ben Milner's clean blend schematic.  The clean blend seems to work fine, but the compressor isn't working.  I've audio probed and there is a good signal at pins 2 & 3 of the 3080E.  9V at pin 7 and pin 4 is at ground.  When I audio probe pin 6 I only get a very slight splattery, gated signal  At pin 5 I only get about 0.6-0.7V as I turn the Sens pot.  If I probe for voltage on the pot side of my R18 I can get 1.0 to about 8.0V as I turn the pot.  I'm kind of at a loss in troubleshooting this.  I've been "ringing out" the traces with the DMM and haven't found any shorts in the tracks anywhere.  I have a Tone Press pedal and I swapped the 3080E chips between the pedals.  The Tone Press works OK but the problem stays the same with my build.    Anyone spot anything from my layout that seems wrong?  Any ideas?

[ibodog]

Here's the schematic links - I worked mostly off of the Orman one (was easier for me to read) but added the optional parts from RG's.

[ibodog]

Any takers on helping me out?  Problem is Dynacomp with quiet, blatty output at pin 6 of the 3080 (need to strum hard to hear anything).

[ianmgull]

I know it's not fun but you might want to follow the steps listed in the debugging thread. 

[ibodog]

I know it's not fun but you might want to follow the steps listed in the debugging thread.  

Are there any steps that I missed in my original post that would help you help me? I started in the debugging thread before I posted. Did you read my description of the problem?

[ibodog]

Anyway, here's the rest of the voltages:

Battery = 9.4V
power at board = 9.4 V
Ground wire where it enters the board = 0V

Vb = 3.0V

Q1
c = 9.4V
b = 2.4V
e = 2.0V

IC1 (CA3080C)
1 = 0.0V (floating)
2 = 0.36V
3 = 0.36V
4 = 0.0V
5 = 0.6V
6 = 2.9V
7 = 9.4V
8 = 0.0V (floating)

Q2
c = 7.0V
b = 2.9V
e = 2.3V

Q3
c = 9.2V
b = 0.0V
e = 0.0V

Q4
c = 9.2V
b = 0.0V
e = 0.0V

Q5
c = 9.4V
b = 9.2V
e = 8.8V

IC2 (TL072CP)
1 = 4.7V
2 = 4.7V
3 = 4.7V
4 = 0.0V
5 = 4.7V
6 = 4.8V
7 = 4.7V
8 = 9.4V

[aron]

Unfortunately I know nothing abut the 3080. But from your description:

've audio probed and there is a good signal at pins 2 & 3 of the 3080E.  9V at pin 7 and pin 4 is at ground.  When I audio probe pin 6 I only get a very slight splattery, gated signal  At pin 5 I only get about 0.6-0.7V as I turn the Sens pot.

http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS007148.PDF

My guess is the problem is somewhere with whatever connects to pin 5.

Wait, if your emitter of Q5 is 8.8V, then why do you only have .6 at pin 5? Look around Q5 - check your trace cuts etc...

[ibodog]

Yeah, that's what I was wondering  - if the voltage range I get at pin 5 is normal for this circuit or not.  Does that 27k resistor from the Sens pot really drop the range from 1V-8V after the Sens pot to 0.6V-0.7V at the pin? 

Visually, everything around pin 5 looks good.  I also used the continuity check on my DMM to make sure there are no shorts around there that I can't see.

At this point I'm baffled what the problem could be.  The blend circuit works because I can blend a clear clean signal with the crappy output of the compressor fine. I'm open to suggestions and would really like someone to try to trace my layout versus the schematics.  I know it's a little difficult because I "blended" the 3 together.  Mostly I followed Orman's schematic but treated R.G.'s schematic as "corrections" and added the 3 recommended parts there.  I did drop the 1uf cap from +9V to ground that is shown on Orman's schematic right next to the diode.  But I don't think that is the cause of my woes.

[ibodog]

Nevermind.  That layout's good.  I grabbed a 20k trimmer instead of a 2k!  :roll:  I'm going to play with adding a tone control and fixing the pot wiring then repost.  BTW the 2k trimmer can be replaced with two 1k resistors in most cases...