Noob feeling like an idiot - could use some assistance...

[Grendel2000]

there are a couple ways to track down the problem...make a signal tester
https://buildyourownclone.com/products/signaltester

or start at the input of 9v and follow until you find an area with no power...then figure out why?..maybe a bad component or bad solder joint..maybe some solder spilled over to the ground...i always test ground to ground areas and hot to hot..just put one clip on 9v adapter +/- and test through out the board with both ..i can usually find the bad spot..hope that is helpful...

I appreciate the effort but you're still a bit over my head...  What do you mean by "and test throughout the board with both"?  What setting do I use on the multimeter?  What am I looking for as far as readings on it go?

Also, can you elaborate on "ground to ground" and "hot to hot"?  How do I know which areas are which?

[jfrabat]

OK, allow me to translate...  I truly feel you, as I felt the exact same way when I started this journey!

First of all, you will need an audio probe.  Don't worry, we will get into that, but in order to USE an audio probe, you will need an amplifier for it.  In my case, I use one of those Blue Tooth speakers that has an audio jack, and use that.  But basically, anything with an audio jack input will work.  Even a guitar amp will work, but it will be a bit more cumbersome to use (unless you got one of those tiny ones you can put on your desktop, then you are golden!).

Now for the audio probe.  The audio probe is nothing more than an audio jack on one side connected to an alligator clip on the sleeve side and a pointy end on the tip side with a capacitor in between.  Depending on what you will use as your amp, you may choose a 1/4" male jack or a 3.5mm male jack.

For mine, I used an old mono mini-jack (3.5mm) extension chord, clopped off one end, soldered half of an alligator clip jumper on the sleeve side, and soldered a capacitor and from there to a metal nail on the tip side (and used some wood dowel to make the grip a bit more comfortable).

Try this link to learn how to McGyver one on the cheap:

Here is a more permanent one (though you will not need 400V cap for pedals; that's more for amps):

If you intend to make more pedals, I STRONGLY recommend you make one of the permanent ones... You will be using it A LOT!

Now, what you do, you start with a signal generator.  There are several choices here, but in my case, I found a looping pedal works wonders!  You then put the alligator clip on the sleeve of one of the jacks, and start chasing the audio signal until you loose it.  Keep in mind, resistors will reduce the strength of the signal, so the volume will be reduced, and that's normal.



In your case, you would start at the input jack (tip side), then go to the input on the board, then pin 2 of the bias pot, then pin 1 (or 3, depending how you oriented it!) of the pot, the C1 and so forth and so on until you get to the output jack. 

Again, hope this helps!

[DIY Bass]

You have the lugs on your output jack reversed.

Quoted because I am not sure you noticed this and he seems to be correct from what I can see.

[Grendel2000]

You have the lugs on your output jack reversed.

Quoted because I am not sure you noticed this and he seems to be correct from what I can see.

I did see that, thanks!  I corrected it this morning and added some new measurements in a previous post.

I appreciate the help!

[antonis]

I understand you're confused a bit about troubleshooting steps but you have to follow some rational sequel..

e.g. Transistor pins measurements are only helpful when are refered on ALL of them..
So plz, post C-B-E voltages (each of them refered to GND) for both Q1 & Q2..
(it should be a good idea to take measurents as close as possible to each particular point, even for theoretically overlapping ones - like Q1 Collector / Q2 Base..)

[Grendel2000]

Ok, here's what I found:

Q1
C - .248v
B - 12.3mV
E - 0

Q2
C - .682v
B - .247v
E - .655v

These were all taken in "9v" mode on my Innova 3320.  Speaking of which, am I using it correctly (is it in the right mode)?  I'm using "9v" setting in the quadrant of the mode selector labelled "Battery Load Test"...

I'm not at all sure that's the right setting.

[willienillie]

No, that is for testing batteries.

Use DCV, one click to the right of OFF.  It is auto-ranging, so that's convenient.

Connect your black probe to the meter at the center "COM" jack.  Connect the red probe to the jack on the right.

Take the measurements with the black probe tip to ground (enclosure or jack sleeve) and the red probe tip to the points you are measuring.

Report back.

https://csr.innova.com/themes/imgs/Innova/products/DigitalMultimeters/Details/Large/3320.jpg

[Grendel2000]

No, that is for testing batteries.

Use DCV, one click to the right of OFF.  It is auto-ranging, so that's convenient.

Connect your black probe to the meter at the center "COM" jack.  Connect the red probe to the jack on the right.

To take the measurements with the black probe tip to ground (enclosure or jack sleeve) and the red probe tip to the points you are measuring.

Report back.

https://csr.innova.com/themes/imgs/Innova/products/DigitalMultimeters/Details/Large/3320.jpg

Will do, thank you...

Ugh - so much to learn.

[Grendel2000]

Ok, measured in the correct mode (DOH!) the values are:

Q1
C - 1.436v
B -.616v
E - 0

Q2
C - 4.04v
B - 1.434v
E - 0.79v

[antonis]

Just to confirm that values posted above are in respect of Q1-C, Q1-B, Q1-E e.t.c. 



If they indeed are, you'll need an audio probe for signal path tracing..

[Grendel2000]

Just to confirm that values posted above are in respect of Q1-C, Q1-B, Q1-E e.t.c. 



If they indeed are, you'll need an audio probe for signal path tracing..

Yes, I believe I tested correctly this time as shown in your diagram.  Thanks for your help!

I guess I need to move forward with getting an audio probe then...

[antonis]

I guess I need to move forward with getting an audio probe then...

I also pressume so..

But before procceding with audio probe, take 2 additional volage measurements on Q2 Collector with R5T at extreme settings (fully CW and fully CCW..) & Contour pot kept on 12 o'clock..

[Grendel2000]

I guess I need to move forward with getting an audio probe then...

I also pressume so..

But before procceding with audio probe, take 2 additional volage measurements on Q2 Collector with R5T at extreme settings (fully CW and fully CCW..) & Contour pot kept on 12 o'clock..

Q2 Collector with R5T:
Full CCW:  8.04v
Full CW: .886v

[antonis]

More than fine for a perfectly working output stage..

You now have to proceed with audio probe starting from Input jack tip, R7, C1, Q1 Base, Q1 Collector, Q2 Base, Q2 Collector, R5T, R5, C3, Volume pot lug 3, wiper & Out jack tip..




P.S.
The above red line isn't actually "original" signal path (it's "discontinued" on both Q1 & Q2 Base-Collector junctions, where "new" amplified signal occurs) but you have to follow it for tracing purposes..

[jfrabat]

The above red line isn't actually "original" signal path (it's "discontinued" on both Q1 & Q2 Base-Collector junctions, where "new" amplified signal occurs) but you have to follow it for tracing purposes..

And do not worry too much if you hear the signal distorted, or its volume reduced after the resistors.  Just make sure the signal is going through...  Also, I tend to start at the tip of the input cable.  If at that point you do not hear anything, you have a short to ground somewhere along the path.

[Grendel2000]

Ok.  I made an improvised audio probe.

I hear signal at the J1 tip/lug.

I hear signal at the lower left lug on the foot switch.

I hear signal at the top right lug on the foot switch.

I get NO signal at the leftmost middle lug on the foot switch (green wire) in either position of the foot switch.

I get NO signal at either lug on the Bias (R7) trim pot.


I don't understand how the foot switch works in terms of which lug is connected or disconnected to other lugs, but it seems significant that I get no signal at all at the bias pot lugs so I have stopped there for the moment.

Is this testing significant?  What should I do next?

[amptramp]

Check your switch - is there any possibility that you have rotated it so the switch poles are going across the switch instead of up and down?  I had to check that on my first build because it wasn't obvious to me at the time.

[Grendel2000]

Check your switch - is there any possibility that you have rotated it so the switch poles are going across the switch instead of up and down?  I had to check that on my first build because it wasn't obvious to me at the time.

I'm not sure what you mean by "poles" here.  When I built it I asked (earlier in this thread I think) if the switch had a specific orientation it needed to be in and the way I understood the response was that as long as the lugs were "horizontal" I was good to go. 

Is that not correct?  You can see the switch / lug orientation in this pic:

[antonis]

I'm not sure what you mean by "poles" here.  When I built it I asked (earlier in this thread I think) if the switch had a specific orientation it needed to be in and the way I understood the response was that as long as the lugs were "horizontal" I was good to go.

Quite right..
You can flip it 180^o with absolutely on problem..



P.S.
Electros don't like sliced haircut..
(especially when done by soldering iron..)

[Grendel2000]

Another potential data point: I have tried checking continuity between the lower left lug on the foot switch and various down-stream points.  I have good continuity at the leftmost middle lug (when the switch is in the correct position) as well as both lugs being used on the R7 pot.  I also get good continuity at the input pad on the circuit board as well as the first leg of C1 but it stops there.

I get NO continuity at the second (downstream) leg of C1 or at Q1: Collector leg.

As I mentioned earlier, I touched that capacitor on accident with my soldering iron during the build.  Is the fact that there is no continuity after it an indication that I killed it perhaps?

Interestingly, I also get NO continuity between the downstream leg of C1 and the Collector leg of Q1, although I DO get continuity between the C1 downstream leg and the next downstream pad (that is empty).  Shouldn't I have continuity between the C1 downstream leg and the Q1 collector?

EDIT: I DO get continuity between the downstream C1 leg and Q1 BASE (but again, NOT to Q1 Collector)...