Pork Barrel problems [FIXED]

[Clayford]

Fixed.
(1) Pork Barrel
(2) No sound. Nothing. Seriously.
(3) Replaced Caps, swapped tl062 and JRC 4558, drank beer, waited 2 weeks, rechecked in/out wiring, foul language uttered in it's general direction, reflowed all solder joints, drank beer, swapped trimmer, burned myself, waited 2 weeks, checked pervious things again, foul language spoken in it's general direction, taken voltages, questioned it's parentage, got shocked, foul language screamed in it's general direction, posted here, beer on deck.
(4) Depth mod - removed and 4k7 inserted for now. LED did very dimly light and cycle. I used a 16 pin IC holder rather than 2 8 pins for the 3102 and 3207 I don't think that matters

v3102 and v3207 chips were sourced from Small Bear. Jumpers under them run N/S
TL062/JRC 4558 original parts from Tayda - replaced at local electronics shop. Still nothing. Voltages here

So I'm at a loss here. The voltages dropping on IC2 pins 3+7 and Q4's 0 V at the emitter definitely bother me, but I have nothing to go by other than it seems "strange". Generally no voltage is bad though right? I don't know if those test points are for anything, I couldn't see anything meaningful on the schematic, and they're not labeled anywhere so I labeled them myself.
Large pics can be found here




I've built cave dweller, afterlife, bloviator,  a fuzz and a noise gate (on vero!) and never had any problems...

Help is most definitely welcome.

[Darkknigh_t]

I haven't built this version but i did build the tonepad one and I have to say that was the first time i had to give up on a board because i couldn't find a problem. If you have no sound coming out my best bet would be solder bridge somewhere. Something is grounding your signal or its not passing through something. Take a DMM and use the buzzer to check if you have any bridges. On mine it was the tiniest bridge i didn't even see with my eye i found it with the buzzer. Next would be to check capacitors polarity could be that you missed something. If you have an oscilloscope try probing starting from the beginning and working your way through the circuit to find out where your losing your signal. Use the schematic to find out where to start looking.
I hope you get it working. I know i had headaches for weeks in situations like that

[brejna]

Hi, since you don't have any sound at all maybe best thing that you could do is make audio probe and check it from input to output following schematic.

[RobA]

R1 looks strange in your photo, are you sure that's a 1MΩ resistor?

Which transistors did you use? Q4's emitter is connected to ground, so that isn't weird. The voltages that look strange to me are all the points that are connected to VD which should be set be the zener D4. Pin 1 on IC3 for example seems low.

[Clayford]

Rob, R1 is a 1MΩ  for pulldown which shouldn't be needed, so I filled the slot with a 0Ω resistor. 2n5088's are used for the trannies, 1N4738A is the zener I used, R4 reads cathode = 5.4v Anode = 0v.

Now I'm no rocket scientist (we'll leave that to Brian) but 5.4v when you're expecting 8.2 is bad. D4 replaced, and I'm now getting 8.2 at IC3 pin 1. Tested old d4 and got 5.4v on a piece of vero,  ... Bad part.

Still no audio out. I'll post up a new batch of voltages then get to work on an audio probe. My schematic reading is terrible( I am getting better), so if anyone could provide the audio path( Brian didn't give us the nice multilayer view of the PCB on this one.)

Clay

[RobA]

R1 goes straight to ground and is taking all of your signal with it at 0Ω. You need to go the opposite direction and leave it out if you don't want to use it for pop reduction.

[Darkknigh_t]

Yes you shorted your signal with ground so just remove the 0 ohm resistor and then see whats happening.

[Clayford]

R1 goes straight to ground and is taking all of your signal with it at 0Ω. You need to go the opposite direction and leave it out if you don't want to use it for pop reduction.

Bad science will get you every time... After removing that 0Ω, everything was great. Added the depth mod back in, replaced the wires making my pots pc mount style( thank you Brian for the trick! ). It's a little tight in there, Small Bear's 3PDT board was just right for the job. I should have played around more with the resistor for the depth mod, but for now it works.

[RobA]

...
Bad science will get you every time... After removing that 0Ω, everything was great. Added the depth mod back in, replaced the wires making my pots pc mount style( thank you Brian for the trick! ). It's a little tight in there, Small Bear's 3PDT board was just right for the job. I should have played around more with the resistor for the depth mod, but for now it works.
...

Congrats and nice build! One mistake's not bad at all considering the complexity of the build and the mods you were doing.

[Darkknigh_t]

Glad you got it working !

[brejna]

+1