SOLVED Abyss rate led stuck on

C

cniers13

Active member
Hello everyone,

Just finished wiring up my abyss pedal. Sounded great and then I noticed the rate led stopped pulsing and is now stuck always lit up. I reflowed as many solder joints as I could and cleaned the board up too. Any ideas?
 
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Updated, swapped out C11-c13 with tant caps, and resoldered the rate pot. LED would pulse for about 2 seconds and then it stayed lit the whole time. Everything looks clean and no debris/cold joints to my knowledge
 
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The LFO is on the edge of working. The power up transient kick-starts the LFO, but it doesn't have enough gain to sustain oscillations. A common problem with phase-shift sinewave oscillators.

I see you used a solder-lug pot for RATE. Are you sure it's B100K? If the two gangs don't track well, that could also stop the oscillator. It can be checked in-circuit. With the power off, set RATE to 0. Measure resistance from ground to pin 3 on one gang and then the other. You have to wait for the reading on the meter to stabilize. Verify that the resistance values match within 10%. Then set RATE to noon and repeat.

Try removing all of the electrical tape on the RATE pot. It might be introducing a leakage path.
 
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Chuck D. Bones said:
The LFO is on the edge of working. The power up transient kick-starts the LFO, but it doesn't have enough gain to sustain oscillations. A common problem with phase-shift sinewave oscillators.

I see you used a solder-lug pot for RATE. Are you sure it's B100K? If the two gangs don't track well, that could also stop the oscillator. It can be checked in-circuit. With the power off, set RATE to 0. Measure resistance from ground to pin 3 on one gang and then the other. You have to wait for the reading on the meter to stabilize. Verify that the resistance values match within 10%. Then set RATE to noon and repeat.

Try removing all of the electrical tape on the RATE pot. It might be introducing a leakage path.
Click to expand...
So they are not close at all. Top was at 219k and bottom was 67k
 
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I think I might have a cold joint as well. When I try to measure resistance on the lug it works but when I measure it on the pad it isn't reading out or it bounces around
 
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Either the pot has a problem or R17 or R18 are the wrong value. Swap the polarity on the meter leads to ensure that C11-C13 are not interfering with the measurement. At the low voltage applied by any decent DMM when measuring resistance, capacitor polarity should not be an issue.
 
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FINALLY, so I grabbed a new rate pot and soldered it with wire, it's long but it works. Redid all the solder joints I can get to and it seems like it is finally working. Thank you for all the help. If I report any issues I will come back but hopefully, this thread is closed! Onto the next builds!!!!
 
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