mkstewartesq
Well-known member
OK, this one has me stumped. One of my very earliest builds (about eight months ago) was the Rangefinder. It has worked fine for the past eight months, other than a minor issue where I could not quite bias the transistor to 7 V. When I flipped it on a few nights ago, I noticed a high-pitched whine (basically a tea kettle whistle) that had never been there before. It appears to be coming from the charge pump (TC1044SCPA). The whine will change frequency if I touch the top of the charge pump or if I touch pin 7 or 8 on the back.
I have swapped out the charge pump with every other 1044S that I have, as well as trying each 7660SCPAZ I have. They all exhibit the same characteristics, with the only difference being the frequency or volume of the whine generated. I have replaced the input and output jack wires with shielded wiring, but that hasn’t helped the problem either.
EDIT TO ADD - I’m also getting some odd faint oscillation on the decay of notes on the higher frets when I apply vibrato, if that sparks any thoughts as to whether this is the charge pump or something else.
This problem exhibits itself even when the pedal is completely completely isolated (not upstream or downstream to any other pedal and on its own dedicated power supply)
Any suggestions as to what I might be missing that would explain why this problem has suddenly popped up after eight months of the pedal working properly? (Pardon some of the sloppiness of the build – as I said, this was one of my very first builds; I’ll go back and clean it up to current standards once I get this whining issue resolved).
Mike
I have swapped out the charge pump with every other 1044S that I have, as well as trying each 7660SCPAZ I have. They all exhibit the same characteristics, with the only difference being the frequency or volume of the whine generated. I have replaced the input and output jack wires with shielded wiring, but that hasn’t helped the problem either.
EDIT TO ADD - I’m also getting some odd faint oscillation on the decay of notes on the higher frets when I apply vibrato, if that sparks any thoughts as to whether this is the charge pump or something else.
This problem exhibits itself even when the pedal is completely completely isolated (not upstream or downstream to any other pedal and on its own dedicated power supply)
Any suggestions as to what I might be missing that would explain why this problem has suddenly popped up after eight months of the pedal working properly? (Pardon some of the sloppiness of the build – as I said, this was one of my very first builds; I’ll go back and clean it up to current standards once I get this whining issue resolved).
Mike


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