Low Tide: Low volume when on

DoctorProfessor

New member
Hi,

I finally got around to getting all the parts into a Low Tide PCB this weekend. All seemed to go well until the final step. When the pedal is off and bypassed it is perfect. Signal goes through, no buzz, no nothing. But when the pedal is on the volume is very very low, even with the "level knob" turned up all the way. In addition it sounds like there is very little modulation on that low volume signal. The LED does turn on as well. I played around with the trim pots to no avail. My next step was going to be getting voltages on all the pins of the ICs. Is there anything that I can do to narrow down my search?

Thanks!
 

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I attached the ground of my DMM to the ground of one of the input jacks. I then probed all the pins of the ICs, does anything look wrong with these?
LM258PVoltage(V)
Pin 1 0.666
Pin 22.5
Pin 32.5
Pin 40
Pin 51.735
Pin 61.735
Pin 71.735
Pin 88.15
MN3207
Pin 10
Pin 20.275
Pin 31.73
Pin 44.7
Pin 55
Pin 65
Pin 71.5
Pin 81.97
LM13700N
Pin 10.66
Pin 24.63
Pin 34
Pin 44
Pin 54.4
Pin 60
Pin 713mV
Pin 80.71
Pin 9Increasing, stopped at 2 V
Pin 100.7mV
Pin 118.1
Pin 127mV
Pin 133.88
Pin 143.89
Pin 154.48
Pin 160.66
CD4044BE
Pin 10
Pin 25
Pin 3hovering around .25v
Pin 4around .3v
Pin 51.2
Pin 61
Pin 71
Pin 80
Pin 91.8
Pin 1050-50mV
Pin 11.6mV
Pin 121mV
Pin 130
Pin 145
Pin 150
Pin 165
MCP602
Pin 12
Pin 22
Pin 32
Pin 40
Pin 52.18
Pin 62
Pin 72
Pin 85
TINY25V
Pin 14.7
Pin 25
Pin 35
Pin 40
Pin 5Jummping around 1.8-2.2
Pin 65
Pin 75
Pin 85
 
Sounds like you might have a short somewhere on the board? And have you also tried tuning the trimpots inside using Fairfield's instructions?
Maybe? It sounds like the "pedal" side is not turning on, I dont get any guitar signal. I read their documentation and tried it out to no avail. I really just get no signal coming out of the thing when it is on.
 
I am feeling pretty lost after staring at this pedal for a bit. Would it be worth it for me to do a more in depth study of the voltages on the ICs? Would it be good to try other chips if I have extras? Not sure what my next debugging steps should be. Any and all help appreciated!
 
After having moved to an entire new home, i had the time to try this again. I put additional tape over any leads on the underside of the Pots. Didnt seem to make much of a difference. But I was able to finally capture the symptom. when bypassed the signal from my Digitech Looper comes through fine, as soon I turn it on though the volume goes very low, but not totally gone. This is with both DIP switches in the "boost" position I believe, and Level turned all the way up.
 
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