dirtboxlayouts Prince-of-Tone | low voltage no output when on

[lukasott]

Hi all,

I recently built the Prince of Tone pedal, but it did not function properly, and I'm facing difficulties in pinpointing the issue. I have thoroughly reviewed all the components and wiring, and I've also employed an audio probe for testing. The audio probe ceased to work at the IC, which suggests that the problem may be related to low voltages.

Here are the details:

The layout: https://dirtboxlayouts.blogspot.com/2021/06/analog-man-prince-of-tone.html

For the IC, I use the RC4558P and D1 -D4 are 1N4148.

True-Bypass is working

Voltages:
IC
Pin 1: 0V
Pin 2: 0V
Pin 3: 0,06V
Pin 4: 0,03V
Pin 5: 0,09V
Pin 6: 0V
Pin 7: 0V
Pin 8: 0,14V

D5
A: 0,6V
C: 0,19V

D1
A: 0,09V
C: 0,07

D2
A: 0,07
C: 0,08

D3
A: 0,08
C: 0,04

D4
A: 0,04
C: 0,1

Top of the board:


bottom:


on-off-on switch: here I'm not sure if I wired this correctly


I wired all the Potis consistently Blue=1 Yellow=2 Green=3



I would greatly appreciate it if anyone could guide me in the right direction.

[duck_arse]

as you can see, you have no supply volts on your board. as we can't see your supply wiring [DC jack?], we can't say if it's a miswire or a short on the board. test the resistance between the pin 8 and pin 4 of the IC [power off, off course].

[lukasott]

Apologies for missing this information earlier. I employ alligator clips to test the board before mounting it into the enclosure.

Here is a picture of the wiring


And here is a picture of the power supply/jack voltage


Resistance between pin 8 and pin 4 seems to be 0,001Ohm

[antonis]

D5
A: 0,6V
C: 0,19V

No power supply going to board..!!

[lukasott]

One more observation: I initially believed that it didn't matter where I connected the ground cable from the DMM, so I connected it to one of the audio jacks. However, I do obtain different values when I connect it to the ground of the DC jack. Here are the (I believe) accurate values.

IC
Pin 1: 1,03V
Pin 2: 1,03V
Pin 3: 1,10V
Pin 4: 1,53V
Pin 5: 1,59V
Pin 6: 1,14V
Pin 7: 1,03V
Pin 8: 1,60V

D5
A: 2,12V
C: 1,75V

D1
A: 1,68V
C: 1,457

D2
A: 1,52V
C: 1,55V

D3
A: 1,54
C: 1,33

D4
A: 1,33
C: 1,67

[PRR]

Resistance between pin 8 and pin 4 seems to be 0,001Ohm

Your meter does not go that low.

However it seems clear that you do have a short after the power protection diode. If you had run it on a battery you would smell it.

[lukasott]

Thank you very much for your assistance. I would greatly appreciate it if you could either help me or direct me to a resource where I can learn how to trace and resolve the short circuit issue. I'm still a beginner, but I'm eager to learn.

[stallik]

At the top right of your solder side picture, there is a stray strand of wire which looks like it might be shorting against the adjacent track.

Curious, why did you choose to attach the wires on the track side? I'm presuming they are links and, of that's the case, it's normal to place them on the other side, together with the components.
That makes it much easier to....

Run a sharp tool, blade or jewellers screwdriver along each of the gaps between the traces to clean off the flux, cr*p and microscopic shorts. I'm not alone in doing this every time I complete a strip board build. Saves hours

[antonis]

[stallik]

The more I look at this image, the more (possible) shorts I see. Please grab a strong magnifier and use it to go down each track, sorting the issues as you go.

[lukasott]

Thanks, everyone!

So, this is my third pedal, and it's my first go at building one on veroboard. I put the links on the bottom because there were some parts overlapping, and it made sense to me at the time. I guess I've learned something for my future builds now.

If I've got this right, figuring out a short is basically a visual thing after you've measured and found the part in the circuit that's likely causing the trouble, right?

I'll look into it and hopefully get it fixed. Thanks for helping out!

[Ben N]

Thanks, everyone!

So, this is my third pedal, and it's my first go at building one on veroboard. I put the links on the bottom because there were some parts overlapping, and it made sense to me at the time. I guess I've learned something for my future builds now.

If I've got this right, figuring out a short is basically a visual thing after you've measured and found the part in the circuit that's likely causing the trouble, right?

I'll look into it and hopefully get it fixed. Thanks for helping out!

Not just/always visual. The continuity setting on your multimeter is also helpful. If touching neighboring parts that don't connect on the schematic produce a beep, you have a short.

[antonis]

Audio signaling isn't always true..
(in the mean of short indication..)

My beloved FLUKE 87 beeps for resistances as high as 90 Ohms..
(in a 9V powered circuit, this calls for 100mA current..)
If that "short" happens before power supply LPF resistor (or in the absence of it), our circuit should work fine (considering a supply capable for total current draw..)