Eternal Burst - Background noise but no guitar signal

[adbernal]

Hi friends,

I have an Eternal Burst in a dual overdrive project with a boost in the front of the pedal. The boost works and the guitar comes through the amp when both effects are bypassed, but im not getting signal when the Eternal Burst is switched on. Turning the 3 knobs do have an effect on the background noise that I can hear, where when all 3 are maxed out there is a low volume oscillating sound that can be "tuned" by the tone knob. BUT get this: I can get sound when I crank the boost into the eternal burst and crank the eternal burst's volume & gain. Its not loud--about the same volume if I rolled my guitar's volume to "3". Unfortunately I boxed before I rocked... so I'll have to come back to you all with pictures of the underside. I do clean my boards and inspect solder joints before wiring up. I will include a picture of the topside of course.
I believe that Im getting the correct voltages on the IC: (values +/- 0.25)
1 - 3.5
2 - 3.5
3 - 3.5
4 - 0
5 - 3.5
6 - 3.5
7 - 3.5
8 - 9v

I tried with A NJM4558 and still didn't work

Diodes and Electrolytics appear to be in the correct orientation, agreed? I checked the resistors and they all appear to be the correct value. Bottom of board not touching back of the pots (I raised it up and insulated to make sure). This doesn't have to do with me not wiring up the LED, does it?

Excited to hear back from you all! And I'll get pictures of the underside . Happy Halloween!

 

[adbernal]

one correction: pin 5 on IC is actually 1.87 approx 2v . Is that standard? The voltage drops from 9v to 2v across R3, a 1M resistor

 

[Robert]

Can you post a pic of your complete wiring?

It looks like you have the DC jack ground connected to the 3PDT where the input jack should be.

 

[BuddytheReow]

Yea. Double check the switch wiring. It will work without wiring the led. Check your ground and jumpers.

 

[adbernal]

Quick response that's awesome! For the pictures, I'll try my best! The yellow wire is connected to the "ground" of the PCB. In is the green & blue wires soldered underneath. Green soldered to "in" and Blue is the "out."

 

[BuddytheReow]

This may help.

2-in-1 Pedal Wiring - PedalPCB Wiki

wiki.pedalpcb.com

 

[BuddytheReow]

Curious. What size enclosure is that?

 

[adbernal]

BuddytheReow, it’s a 1590bb but I used the wide angle on my iPhone so it has that fishbowl effect

 

[adbernal]

Reflowed all the contacts and rewired the board. Unfortunately, the same problem still. I used an audio probe and get signal at C1 but not on pin 5 of the ic.
Whatcha guys think? This isn’t my first dual OD with this wiring scheme, but this is my first time with this particular problem. Usually it’s dead signal from a short somewhere for me. But since I get signal when I throw a loud boost in front I’m really curious and stumped at the same time.

 

[BuddytheReow]

Double check with your meter if all the diodes are working properly (one way)

 

[adbernal]

Good idea!
Get 0.68v forward voltage on the 1N914 diodes and 0.19v on the 1N5817. So they’re looking good.
Is it possible that it’s the 3pdt or one of the pots?
I’ll bypass the switch and see if that changes anything.

 

[adbernal]

The cap I’m using for C5 is 10uF and 16v, any chance it could have blown from excess voltage? I’ve got another eternity that I built just like this one and I’m cross referencing the two. I used a 25v cap for C5 on the one that works.

 

[fig]

+1 on the pcb's 3PDT wiring. I don't think that is the ground lug.