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Tech Help - Projects Page / NomNom v.2020 passes unaffected signal when engaged.
« on: September 27, 2020, 05:13:00 PM »
Hello,
I am working on the latest version of the NomNom (Phase 90). I am getting a clear signal when engaged but not phasing. I have been through the board with an audio probe and the clean signal/rate pot section seems to be the problem. I have signal at the emitter of Q1, but when I move on to R25, and the other spots in that section (including the right side of IC1), I get a faint heartbeat type flopping noise that speeds and slows when I adjust the pot. The left side of IC1 is passing signal as normal, along with all the other two ICs. I've tries adjusting T1 with no change. Voltages seem okay. I've tried 4 different TL072s in IC1 with no change. Hoping this is a common thing that someone will notice right away. Thanks!
1 Spot power supply at 9.42v
On all three ICs 1-3 and 5-7 are 3.85v, 4 is 0 and 8 is 9.16
Q1 is 2.27C 2.8B 3.85E
Q2-5 all three pins are at 3.85 or very close to it
I am working on the latest version of the NomNom (Phase 90). I am getting a clear signal when engaged but not phasing. I have been through the board with an audio probe and the clean signal/rate pot section seems to be the problem. I have signal at the emitter of Q1, but when I move on to R25, and the other spots in that section (including the right side of IC1), I get a faint heartbeat type flopping noise that speeds and slows when I adjust the pot. The left side of IC1 is passing signal as normal, along with all the other two ICs. I've tries adjusting T1 with no change. Voltages seem okay. I've tried 4 different TL072s in IC1 with no change. Hoping this is a common thing that someone will notice right away. Thanks!
1 Spot power supply at 9.42v
On all three ICs 1-3 and 5-7 are 3.85v, 4 is 0 and 8 is 9.16
Q1 is 2.27C 2.8B 3.85E
Q2-5 all three pins are at 3.85 or very close to it