Ping troubleshooting

[midwayfair]

Post your voltages on all active device pins.

Use a fresh op amp. Putting them in backwards is a good way to kill them.

Audio probe. See if you get any signal at R2 /C1, pins 1 and 7 of the op amp (you won't get signal elsewhere on the chip because it's an inverting op amp), the base and emitter of Q1, and pins 2 and 3 of the verb pot. You can check the pins of the brick if you lose it between the last two areas.

Folks, can we PLEASE remember to at least ask for voltages and audio probe results before speculating and potentially sending people on wild goose chases?

[LateCentury]

Volt meter. No idea what I'm doing... What setting do I need to have this on? I'm getting quick flashes of numbers, and when HOLD is on, nothing.

https://flic.kr/p/FSnTN1

[Jebus]

The blue ones on the left are DC. The number is the maximum voltage you can measure with that setting. So, since this is a 9V pedal you should use the blue 20 on top left. Attach the black common cable to ground (such as sleeve of either jacks) and measure the voltages with the red cable.

Here's a great tutorial video about measuring voltages: https://www.youtube.com/watch?v=idWhtCU7xw0

[LateCentury]

Thanks a ton!

Here are my readings:
IC 1
1-4.18
2-3.76
3-2.24
4-0.00
5-2.24
6-4.17
7-4.19
8-4.49

IC2
1-2.51
2-0
3-----
4-0
5-0
6-0
7-1.27
8-1.25
9-1.27
10-1.25

Q1 (right to left, flat spot facing downward)
3.87
4.09
4.5

Reg (right to left, flat spot facing down)
2.51
0
4.49

[LateCentury]

I should also note, tried two other TL072's and got similar readings

[LateCentury]

From the looks of it, it seems like my voltages are about half what they should be across the board.

[m-Kresol]

what power supply are you using and what is the voltage reading on the +9V input? You are definitely having a problem somewhere in your power supply. the regulator needs more than 5V to put out steady 5V, and without that the reverb brick won't do anything..

[selfdestroyer]

On the same note as Felix above.. check your pinout on your regulator. I have had some that the pins were flipped 180 degrees from the mask on the board.

Hope this helps

Cody

[LateCentury]

what power supply are you using and what is the voltage reading on the +9V input? You are definitely having a problem somewhere in your power supply. the regulator needs more than 5V to put out steady 5V, and without that the reverb brick won't do anything..

I'm using one of those One Spot adapters with a daisy chain powering several other pedals. They all power up and work just fine. I've plugged it into a at least one other adapter with the same result.

[LateCentury]

On the same note as Felix above.. check your pinout on your regulator. I have had some that the pins were flipped 180 degrees from the mask on the board.

Hope this helps

Cody

Thanks, i'll give that a shot too

[m-Kresol]

hmm. I can't be the regulator alone. You've also got low voltages on IC1, which should get 9V supply voltage on pin8! Check the voltage on the supply pin and on the cathode (-) of D1. Hope you get it sorted, good luck

[LateCentury]

Completely different readings today,  and all I've done was put the project away for a few days. The input wire did come disconnected at some point, so I re-attached that. But still no signal:

IC 1
1-8.41
2-6.91
3-4.50
4-0.00
5-4.51
6-8.37
7-8.43
8-9.03

IC2
1-5.05
2-0
3-----
4-0
5-0
6-0
7-2.56
8-2.52
9-2.55
10-2.52

Q1 (left to right, flat spot facing downward)
7.81
8.14
9.05

Reg (left to right, flat spot facing down)
5.05
0
9.05

Cathode end of D1 is 9.05

Power input is 9.33

In my last readings I mistakenly said right to left when i meant left to right on the REG and Q1 readings. I haven't flipped the REG yet.

[m-Kresol]

ok, readings look better now! Don't switch the regulator, it's fine like that (puts out 5V).
You seem to have a problem at IC1 though, all voltages are higher than what it says in the doc.
your Vb (pin 3 and 5) are good, so the voltage divider and the cap are ok too.

I actually don't know what's causing your increased voltages as my knwledge about opamps is really limited. One possibility would be a solder bridge?

[LateCentury]

I checked out all the solder joints... Not seeing any bridges any where. Now I'm starting to think I may possibly have it wired incorrectly.  Here's a sketch of the tracing of the wires:

[lincolnic]

You've got power wired to the wrong lug of your DC jack. You want the middle lug, not the outside one -- that's the battery disconnect terminal.

I made this mistake on two builds in a row before learning not to do it a third time.