No signal from Wonder Drive build

[Jared]

I’m working on a Wonder Drive pedal. I got it all built out and I’m not getting signal through the pedal when the switch is on.
I’ve checked for solder bridges, and made sure all polarity in the separate components are correct.
I’m using a tester and going through the circuit and I’ve come to the point where the signal does not pass through; it’s after the first transistor in the signal. I’ve switched out transistor and the same thing is happening. No signal is coming out of pin 1 and progressing to the next resistor.
I’ve attached a picture to help visualize. (Green is good to go, red is where the signal stops)
Any help would be greatly appreciated!
Thanks!

 

[Jared]

Thank you so much for the inquiry! Here are my answers:

-I don't have any sound on pin 1 from Q1, but I do have sound on pin 2.

-I have NO sound on C2 for (either side).

-I have NO sound on R7 (either side).

-My meter is reading 10k between Q1, pin 1 and one side of R7 is reading 10k while the other side is reading 0.

 

[zgrav]

do you get an voltage reading on pin 3 for Q1?

 

[Nostradoomus]

Make sure there are no strays wires shorting each other out in these areas here. Best practice with stranded wire is to twist the end up tight, tin it with solder so it stays together, then feed it through and solder it in.

 

[Jared]

do you get an voltage reading on pin 3 for Q1?

Im reading .03 volts for pin 3 on Q1

 

[Jared]

Make sure there are no strays wires shorting each other out in these areas here. Best practice with stranded wire is to twist the end up tight, tin it with solder so it stays together, then feed it through and solder it in.

View attachment 5988

Thank you. I actually went through and cleaned that all up and made sure nothing was shorting out along with when I went through and re-flowed the rest of the solder joints.

 

[zgrav]

try removing Q1 and measuring the voltage you are getting in the socket for pin 3. Is it still 0.03?

 

[Jared]

try removing Q1 and measuring the voltage you are getting in the socket for pin 3. Is it still 0.03?

Voltage is 0.03 coming from the socket for pin 3 if I remove Q1.

 

[zgrav]

Look at the schematic and you can see that power should be coming through the 1N5817 diode and connecting to pin 3 of Q1. See if you have power at the diode. If you do, figure out why it is not reaching Q1 pin 3.

 

[Jared]

Look at the schematic and you can see that power should be coming through the 1N5817 diode and connecting to pin 3 of Q1. See if you have power at the diode. If you do, figure out why it is not reaching Q1 pin 3.

I’m reading that I have power at the diode (I noticed that the voltage is reading negative on my meter, even at the power jack. I’m not sure what difference this makes).
From the diode, the power immediately goes to -0.03 volts when connecting to C11. Then from there it remains -0.03 volts when connecting to IC pin 8.
If I trace the back of the PCB, it seems Q1 pin 3 is connected to IC pin 8 where the power is -0.03 volts.
I’ve attached photos for reference.

 

[zgrav]

If you have your probes on the meter oriented correctly, it makes a lot of difference if you get a positive or negative voltage. Make sure you have a positive voltage on your PCB at the top beside the LED. If that is negative you need to switch the wires at your DC jack.

 

[Jared]

If you have your probes on the meter oriented correctly, it makes a lot of difference if you get a positive or negative voltage. Make sure you have a positive voltage on your PCB at the top beside the LED. If that is negative you need to switch the wires at your DC jack.

I believe the probes on my meter are mounted correctly (photo attached). If I meter the AC adapter directly, it reads positive voltage. When I meter the voltage at the top of the PCB it reads negative. If I switch the wires at the DC jack the pedal does not power on (LED does not light up). But it does seem to turn on when I have the wires oriented in the way that reads a negative voltage.

 

[zgrav]

If you check the + and - wires at your PCB do you get a positive voltage? You should. If you get a positive voltage at the + pad, check the voltage on pin 3 of Q1 and see what it is. If you are getting voltage there, you should check and see if the pedal is working even if the LED is not lighting up. There is a chance that the power was the only issue. And even if you still don't have sound, you can use your audio probe to see if you are now getting sound on Q1, pin 1.

In any case, if you change the wires coming from the DC jack and get a positive voltage on Q1, pin 3, swapping the leads on your LED should get it to light up when the board is powered on.

 

[Jared]

If you check the + and - wires at your PCB do you get a positive voltage? You should. If you get a positive voltage at the + pad, check the voltage on pin 3 of Q1 and see what it is. If you are getting voltage there, you should check and see if the pedal is working even if the LED is not lighting up. There is a chance that the power was the only issue. And even if you still don't have sound, you can use your audio probe to see if you are now getting sound on Q1, pin 1.

In any case, if you change the wires coming from the DC jack and get a positive voltage on Q1, pin 3, swapping the leads on your LED should get it to light up when the board is powered on.

Switching the +\- wires at the top of the PCB along with the leads to the LED seemed to clear up the voltage issue. Which is interesting because my DC jack is not labeled and I was told that the short connection point is supposed to be (-) but if it works properly, I have the short connection point as (+) (photo attached [wires are temporarily connected])

The audio signal still does not pass through the pedal when the pedal is switched on. I have attached reference photos.

 

[Nostradoomus]

What kind of power supply do you have?

 

[Jared]

Switching the +\- wires at the top of the PCB along with the leads to the LED seemed to clear up the voltage issue. Which is interesting because my DC jack is not labeled and I was told that the short connection point is supposed to be (-) but if it works properly, I have the short connection point as (+) (photo attached [wires are temporarily connected])

The audio signal still does not pass through the pedal when the pedal is switched on. I have attached reference photos.

If you check the + and - wires at your PCB do you get a positive voltage? You should. If you get a positive voltage at the + pad, check the voltage on pin 3 of Q1 and see what it is. If you are getting voltage there, you should check and see if the pedal is working even if the LED is not lighting up. There is a chance that the power was the only issue. And even if you still don't have sound, you can use your audio probe to see if you are now getting sound on Q1, pin 1.

In any case, if you change the wires coming from the DC jack and get a positive voltage on Q1, pin 3, swapping the leads on your LED should get it to light up when the board is powered on.

Better quality

 

[Jared]

What kind of power supply do you have?

I’m using a universal power supply for testing. You can switch out the connectors. I believe I have it oriented correctly.

 

[Nostradoomus]

That’s positive ground...you’ll want to flip that and rewire your dc jack the other way around. Might need to replace your 1n5817 too.

 

[Jared]

That’s positive ground...you’ll want to flip that and rewire your dc jack the other way around. Might need to replace your 1n5817 too.

View attachment 6001

Thank you for the insight!

I flipped it and changed the DC jack around. Everything is reading positive.
The power to the 1n5817 is reading 9.28v. Should it still be replaced?

I am still not getting audio signal through the pedal when the switch is on. I’ve attached a couple of pictures for referencing where signal can be heard.

Some things of note:
-all of the points where I’m getting signal are only on one pin accept for R5, the IC, and Q1 (Q1 = pin 1 and 2 are clean signals, pin 3 is distorted)

-Only pin 3 and pin 8 are getting signal for the IC. (3 is clean 8 is distorted)

 

[zgrav]

if you are reading 9.28v on one side of the in5817, what is the reading on the other side?

look at the schematic and figure out where the connections from the in5817 are supposed to go (to a specific part, transistor pin, or IC pin -- not through that part to somewhere else). Your next step is to make sure power is actually going where it is supposed to in the circuit -- use you DMM to see if the power is actually reaching each of those places, and note what the readings are at the transistor legs and IC legs.

after you do that with the power, do the same thing making sure you have connections to ground everywhere you are supposed to.

after you confirm those things you can start using the audio probe again to see if you are making progress.

 

[Jared]

if you are reading 9.28v on one side of the in5817, what is the reading on the other side?

look at the schematic and figure out where the connections from the in5817 are supposed to go (to a specific part, transistor pin, or IC pin -- not through that part to somewhere else). Your next step is to make sure power is actually going where it is supposed to in the circuit -- use you DMM to see if the power is actually reaching each of those places, and note what the readings are at the transistor legs and IC legs.

after you do that with the power, do the same thing making sure you have connections to ground everywhere you are supposed to.

after you confirm those things you can start using the audio probe again to see if you are making progress.

If you dont mind me asking, On the schematic, how exactly can I tell that something is supposed to be connected to the in5817? Does the VCC indicate this?

Also, I CAN tell what is supposed to be grounded by looking at the schematic, but I'm not exactly sure how to CONFIRM that it is being grounded.