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Touchstone Chorus - bad voltages on IC2

Started by RobW, July 09, 2021, 12:30:25 AM

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RobW

Having a bit of trouble with voltages on one of the chips in this build.
Here's what I have for IC2 - MN3007
Position --- should be --- I get this
1 --- 8.49 --- 8.38
2 --- 4.2 --- 4.1
3 --- 4.1 --- 1.2
4 --- 0 --- 0
5 --- 0 --- 0
6 --- 4.2 --- 4.1
7 --- 3.99 --- 8.25
8 --- 3.99 --- 8.25

these measurements are all taken without the chip in, so I don't think it's the chip itself.
Any suggestions on how to correct the issues with pins 3, 7, and 8 ?

madbean

Voltage measurements can depend on current draw of the chip and voltage outputs on the individual pins on the IC under power. Pins 7 and 8 should drop with the MN3007 in. Pin3 - if you still have low voltage with the chip inserted take another look at R15 and R16. Make sure those values are correct and use a resistor color band calculator if needed.

RobW

Thanks Brian,
I checked the measurements with the chip in as well, and the measurements were similar to what I posted.
I'll check the resistor values you mention as well to see if that resolves the issue.
I'm fairly new to pedal building, and have lots to learn about the troubleshooting part of this.
So thanks for the advice!
I've received a lot of great feedback in the forum so far.
Nice to have a place to go for problem solving.