Polyhog (Polysaturator clone) troubleshooting

[basilisk]

Long time lurker, first time poster here...

This one has been sitting in my "problems" pile for quite some time - it's a Pigtronix Polysaturator clone, built with "Polyhog" board from PedalPCB (schematic: https://www.pedalpcb.com/docs/Polyhog.pdf).
The problem itself: the output volume is very low, almost non-existent, I have to turn amp volume all the way up to hear anything. After a few unsuccessful attempts to tackle the issue, still not wiling to admit defeat, I decided to double down and ordered another board... long story short, the second build had the exact same outcome. Audio probe that usually helps didn't pinpoint any obvious places where signal loss occurs. In that regard, "no sound whatsoever" problems are easier to troubleshoot.
It's obvious that I've done something incredibly stupid (and, apparently, at least twice), I just don't see it. Any help is appreciated!

Q1 (J201):
D: 5.80v
S: 1.46v
G: 1.14v

IC1 (RC4558):
1 - 1.43v
2 - 1.47v
3 - 1.42v
4 - 0
5 - 4.3v
6 - 3.4v
7 - 1.42v
8 - 8.7v

IC2 (TL072):
1 - 5.76v
2 - 5.81v
3 - 5.79v
4 - 0
5 - 1.42v
6 - 1.34v
7 - 1.43v
8 - 8.7v

IC3 (RC4558):
1 - 1.46v
2 - 1.46v
3 - 1.42v
4 - 0
5 - 1.43v
6 - 1.43v
7 - 1.46v
8 - 8.7v

IC4 (CD4049):
1 - 8.7v
2 - 8.7v
3 - 0
4 - 2.89v
5 - 2.89v
6 - 2.89v
7 - 2.89v
8 - 0
9 - 2.90v
10 - 2.92v
11 - 2.91v
12 - 2.89v
13 - 0
14 - 0
15 - 8.7v
16 - 0

IC5 (RC4558):
1 - 1.45v
2 - 1.45v
3 - 1.42v
4 - 0
5 - 1.42v
6 - 1.45v
7 - 1.45v
8 - 8.7v

[Slowpoke101]

Welcome to the forum. It's a great place.

With your voltages the most immediately noticeable problem is your Vref voltage rail is at 1.42V It should be about 4.3V to 4.6V This voltage is supplied via pin 7 of IC1. Pin 5 of IC1 is at 4.3V which is OK but pin 7 and 6 are at different voltages but the circuit shows them as connected together. Check this area for damaged tracks or solder splashes (thoroughly check the entire board ).
If you think that everything is correct with IC1, remove all other chips and measure the voltage on pin 7 of IC1. If it has come up to about 4.5V then start to reinstall each chip one at a time and then checking the voltage on pin 7 of IC1 to see if it falls back to 1.43V. If it does fall then the chip that you just put in may be faulty and should be replaced.
If the voltage on pin 7 of IC1 did not come up when all the other chips were removed, replace IC1 and check the voltage again. If that doesn't help, things get more complicated.
Uploading some pictures of both sides of your board would be very helpful too.

Again, welcome.

[basilisk]

Yes!!! That was it! There was no connection between IC1 pins 6 and 7 - looks like pin 6 on the PCB is not going anywhere
Which actually is good news, it means I'm not crazy! 
Thank you for your help!