NOOB Question Regarding Debugging First Stompbox

[Govmnt_Lacky]

Where I am having a problem is with resistors R11 and R2, I get 7.8 volts on one end and ) volts on the other for each. Thanks.

If what you meant to say is ZERO or 0 volts on the other for each.... then that is exactly what you should get! If you look at the layout/schematic, you will see that both R11(1K) and R2(33K) are tied to GND (or V-) on one side. So you should NOT read any voltage because one side of each resistor is tied to GND. (or V-)

[texstrat]

Ok, let me reiterate, using this layout, http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

I get the following voltages for resistors in position R11 and R2:

R11 (1K) 7.06V lead facing the L pad, 0.1V lead facing R3
R2 (33K) 0.0V lead facing 9V pad, 7.80V lead facing Q2

Contour pot
M1 wire 0.0V
M2 wire 0.7V

I have a plug in the input jack and the effect on. DMM is grounded to the DC ground.

Any ideas?

[Govmnt_Lacky]

Ok, let me reiterate, using this layout, http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

I get the following voltages for resistors in position R11 and R2:

R11 (1K) 7.06V lead facing the L pad, 0.1V lead facing R3
R2 (33K) 0.0V lead facing 9V pad, 7.80V lead facing Q2

Contour pot
M1 wire 0.0V
M2 wire 0.7V

That looks right to me... so far.

You may want to shelf this for a day and revisit it tomorrow. Start out fresh with a clean head.

[texstrat]

Good idea.

[Jhouse]

I recently had a problem where I used a 440 ohm resistor instead of a 440k resistor. This threw off the bias on my transistors completely. This is going to sound silly, but make sure that you have the right values in the right slots. In other news, the collector of Q2 is right in your circuit. Usually you want it around 4.5v and you can use the trim pot to adjust it.

I think that there is something fish with Q1. I do believe it could be screwing up the base and emitter on Q2 also. I'm just not exactly sure what is wrong with it.

[texstrat]

Here are some new pictures, maybe someone sees something I am missing:

[texstrat]

Ok, I have now had a chance to sit down and look over the project and check voltages. With my battery at 9.02 volts, 1/4" jack in the input, I check the entire board and noticed a problem near the trimmer, R5T. I set the trimmer at 4.5V so that the collector on Q2 would read 4.5V, which it does.

My voltage goes from 4.5V to 2.7V on the leg going to the 1K resistor at R5, below is a image of all the voltages I collected.

Why is there such a big drop in voltage? the two resistors and one capacitor check close to their values.

Also I have a 1M resistor in place just below the first wire off the bias pot to the board.

[texstrat]

Looking at this layout, http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

I get the following voltages starting at the collector @ Q2 4.5V

Trimmer pot (R5T) 4.5V, middle 4.5V, right 2.7V
Resistor (R5) closest to trimmer 2.7V, towards C3 1.5V
Capacitor (C3) 8.5V, towards V3 1.1 V
Resistor (R4) 1.1V towards trimmer, 0.8V along M2

Why is there a nearly 2V drop on the trimmer legs?

[texstrat]

Anyone have any ideas as to what is going on with the voltages? Is this too basic a question to ask in the forum?

[texstrat]

Buehler?

[Ymir]

Hey texstrat,

Did you ever figure out the problem? I am in the same boat. I'd like to hear a solution if I'm lucky.