Big Muff Pi Build (Green Russian) - Troubleshooting - No Sound

[ericlaw02]

Hi, noob here, I built a Green Russian Big Muff Pi, and I get no sound at all with the effect on (only bypass works).

Built with the layout from http://effectslayouts.blogspot.com/2016/05/electro-harmonix-big-muff-1590a.html, which corresponds to the Kit Rae schematic here (http://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part3.html).

So far I can see the transistor voltages are completely messed up, but I have no idea why it's that way (no electronics background, only know how to solder ):

Power In: 9.13V
Q1: C=6.96V, B=7.7V, E=6.96V
Q2: C=0.87V, B=0.87V, E=0.26V
Q3: C=0.88V, B=0.87V, E=0.26V
Q4: C=0.88V, B=0.87V, E=0.26V

D1: A=0.63V, K=0.88V
D2: A=0.88V, K=0.63V
D3: A=0.62V, K=0.88V
D4: A=0.88V, K=0.62V

Reference transistor voltage for reference: (Q1, Q2, Q3, Q4 order in reverse versus compared to Kit Rae schematic)
http://www.generalguitargadgets.com/pdf/ggg_bmp_instruct.pdf

I've gone through the board with a light and I couldn't find any bridges, tried wiggling everything for cold solder joints and still no dice.

[antonis]

Could you post some photos of your build..??
(both items and soldering PCB side..)

[iainpunk]

i have a strong suspicion that R10 R11 and R18 are the wrong values.
we need to see the pictures of the board to be sure tho

cheers, Iain

[ericlaw02]

Hi, thank you both for your help!

Finally got to the taking the photos:
Component side: https://i.imgur.com/fLs5fir.jpg
Component side (with light underneath): https://i.imgur.com/KiuHRjz.jpg
Trace side: https://i.imgur.com/u9pRRSw.jpg

In-circuit resistance:
R10: 377 ohm
R11: 10.4k ohm
R18: 10.8k ohm

EDIT: Supplemented photo for the resistor hidden between the 103J & the transistor on the top left corner: https://i.imgur.com/u34Ozaw.jpg
EDIT2: Also supplemented mapping between component values and the schematic I did for debugging purposes: https://i.imgur.com/ZHmAtvR.jpg.
Also realized the photo doesn't show the transistor types, they are all 2N5088s.

[antonis]

Trace side: https://i.imgur.com/u9pRRSw.jpg

Don't get me wrong but that's unacceptable both for solder joints and tracks/pads etching..

[Keeb]

So it seems you have a solder bridge here
https://imgur.com/a/IrTddcS

There might be more but it's difficult to make sure from your photos. I would suggest audio probe or going over the pcb and checking continuity along the traces (and their neighbors!) to find any bridges/open tracks.