Finally got the foxrox octron working

Started by Lost_soul, February 13, 2025, 02:01:33 PM

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Lost_soul

Quote from: Rob Strand on Yesterday at 08:28:13 PMIt's the circuit with the switch and C21.



It's pretty normal to go over a circuit and kick the tires a bit.   No matter how much time you spend on it, next week you will think of something else  :icon_mrgreen:


Clearly pins 6 and 7 are connecting, even from the voltages.  You can get weird results like that when there's a bad connection (somewhere).  If pin 5 is really different to pins 6 and 7 I'd start to be suspicious the opamp has a problem.

Well you ARE right!!! The opamp really was the problem. I changed it and bam the voltages now across pins 5,6,7 are the same 4.8v. Thank you rob. Now as I understand the voltages are all right. I wish I could figure out how to read voltages and know what they should be at any point in a schematic but idk where to start.
I will try your mod in the morning and report back as it's 3 am here.
Thank you again man.

Rob Strand

Quote from: Lost_soul on Yesterday at 09:08:00 PMWell you ARE right!!! The opamp really was the problem. I changed it and bam the voltages now across pins 5,6,7 are the same 4.8v. Thank you rob. Now as I understand the voltages are all right. I wish I could figure out how to read voltages and know what they should be at any point in a schematic but idk where to start.
I will try your mod in the morning and report back as it's 3 am here.
Thank you again man.
Cool you are pretty much there now.

For a lot of circuits the input and outputs of the opamps should all sit at about Vref (Vcc/2 or whatever).  There are a few instances where the multimeter loads down the voltages and you get less than Vref but you can have an idea that's going to happen if you see a 470k or 1M resistor there.   Things like oscillators/LFO are different.
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