Blues jr low voltage problem

[pontiacpete]

Then insert your DC current meter between the negative output of the power supply and the negative end of the cap.

Also you should disconnect R53 as well as the zener to avoid a current flowing back into the amp's power supply.

I’m seeing about 3.1mA across the negative terminal

[Helmholtz]

I’m seeing about 3.1mA across the negative terminal

What do you mean with "across the negative terminal"?

Is that with the opamp in?
Did you adjust to 15V?

[pontiacpete]

What do you mean with "across the negative terminal"?

Is that with the opamp in?

I inserted the meter between the neg on the supply and the neg of the cap. OP amp was out

[Helmholtz]

Ok, now reinsert the opamp and measure current again with voltage at 15V.

[pontiacpete]

Ok it’s .14mA

[g1]

Why is that decimal place there? Is it 14 or 0.14mA ?

[Helmholtz]

Does the current change with the "fat" switch setting?

[pontiacpete]

It moves between .11 to .16 when pressing fat switch

[g1]

So you had 3mA with the IC out, and it dropped to 0.14mA with the IC in?

[pontiacpete]

Yes I think that’s what happened

[g1]

Looking at the reverb circuit, does D14 measure good? What resistance do you measure across R40 ?

[pontiacpete]

R40 is 79 ohms
D14 14 is 39K black probe on the anode the stripe
reversing the probes I get a rising voltage from 260k to 650k

[Helmholtz]

I don't believe a current of 0.14mA. That's 140ľA or close to nothing.
Nominal current of the 4560 is 4mA to 5mA.

[pontiacpete]

I don't believe a current of 0.14mA. That's 140ľA or close to nothing.
Nominal current of the 4560 is 4mA to 5mA.

I don’t know why my measurement is wrong. I do have R53 disconnected

[Helmholtz]

Might be time to try a different meter.