Musikding Bluelay pedal help! First build. Virtually no output.

[monte]

Hey guys,

This is the first pedal I have built and it sadly doesn't work. I've followed all the instructions, triple checked all components and did all the troubleshooting suggested here with no success. When plugged in, I get the guitar sound on bypass mode, but when switched on, I get virtually no sound at all. I say virtually because initially I thought there was no sound at all coming through, but I noticed that when I crank the amp up to almost max, I can hear a faint guitar tone through, but with no effect added. The LED lights up, all continuity tests beep fine. I am getting very low voltage at the IC's, so I am thinking that might the problem, but I don't really know how to fix it. I've tried de-/re-soldering a few components that I thought could be the problem, but now my board just looks messy on the backside and it still doesn't work. Anyhow, here's the full brief:

1.What does it do, not do, and sound like? - 'No' output when turned on. Works on bypass.
2.Name of the circuit = Das Musikding Bluelay
3.Source of the circuit (URL of schematic or project) = http://diy.musikding.de/?p=856&lang=en
4.Any modifications to the circuit? No
5.Any parts substitutions? No
6.Positive ground to negative ground conversion? No
7.What is the out of circuit battery voltage? 8.65v
Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = 8.58v
Voltage at the circuit board end of the black battery lead = 0v

I found it confusing also how the schematic shows R5 being a 12k resistor, but R5 on the board is a 3 hole resistor, so I installed the only thing that fitted there, which is a 25k mini trimmer. I did a bunch of googleing and couldn't find much on that also.

Measured voltages:

IC1

Pin 01 - 0.65v
Pin 02 - 0.65v
Pin 03 - 0.55v
Pin 04 - 0v
Pin 05 - 0.55v
Pin 06 - 0.67v
Pin 07 - 0.67v
Pin 08 - 1.11v

IC2

Pin 01 - 0.4v
Pin 02 - 0.2v
Pin 03 - 0v
Pin 04 - 0v
Pin 05 - 0.01v
Pin 06 - 0v
Pin 07 - 0v
Pin 08 - 0v
Pin 09 - 0v
Pin 10 - 0v
Pin 11 - 0.01v
Pin 12 - 0.01v
Pin 13 - 0.01v
Pin 14 - 0.01v
Pin 15 - 0.01v
Pin 16 - 0.01v

IC3

Pin 01 - 1.11v
Pin 02 - 0v
Pin 03 - 0.4v

Zener ( D1)

Anode - 0v
Cathode - 1.12v

Here are a few pictures of my build:

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/IMG_4641.JPG.html
http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/IMG_4639.JPG.html

If anybody could help out, that'd be fantastic! I am super excited to take this up as a hobby, but a little discouraged at the same point. I guess that's part of the fun?

Thanks in advance!
E

[Kipper4]

Is D1 orientated correctly? I can't tell from the photos.

[monte]

I believe so! I followed the print on the board, and oriented the band to the same side.

Here's a pic: https://www.dropbox.com/s/sy8tvmc7ekjkdu6/IMG_4643.JPG?dl=0

[Kipper4]

Do you have a solder bridge somewhere on the power supply. I think your power supply might be shorted from +9v and gnd.
I would expect +9v on pin 8 of ic1
Does the battery get hot?

[samhay]

Something is dropping the voltage from your battery to 1.11V, which is far too low for your circuit to work.
I would check the value of R7 - it should be 33R and the problem suggests it is larger than this in your build. As a quick test, you can short it out - connect both ends together, which should bring your build to life.

Edit:

>I think your power supply might be shorted from +9v and gnd.

I don't think so, as the Vref is sitting at half the V+ the op-amp and voltage regulator are seeing.

[monte]

that might be it! this is a pic of R7:

https://www.dropbox.com/s/vm2d70hb5mcvy1t/IMG_4640c.jpg?dl=0

looks like it's a 33k Ohms 1% resistor as opposed to a 33 Ohm. i am assuming the kit came with the wrong one.

i'll try shorting it out, that won't ruin anything right?

[samhay]

that might be it! this is a pic of R7:

https://www.dropbox.com/s/vm2d70hb5mcvy1t/IMG_4640c.jpg?dl=0

looks like it's a 33k Ohms 1% resistor as opposed to a 33 Ohm. i am assuming the kit came with the wrong one.

i'll try shorting it out, that won't ruin anything right?

I am just colour blind enough to struggle to see band colours against the blue of metal film resistors.

Shorting it wont do any harm - it is there as part of a power supply filter. If you have a good (quiet) power supply, or run it off a battery, you can replace it with a piece of wire.

[monte]

great, i'll try that now! the colour on the resistor installed are orange, orange, black, red, brown.

[samhay]

That sounds like 33k, which would certainly explain your symptoms.

[monte]

so, i removed the resistor R7 and replaced it with a piece of wire. i can hear the delay now, but i still have the same volume problem. when the pedal is on, i can only really hear it when the amp is cranked to max, and it's still quite low. any other ideas? here are my new readings:

IC1

Pin 01 - 0.67v
Pin 02 - 0.86v
Pin 03 - 4.02v
Pin 04 - 0v
Pin 05 - 4.02v
Pin 06 - 0.9v
Pin 07 - 0.9v
Pin 08 - 0.4v

IC2

Pin 01 - 4.94v
Pin 02 - 2.48v
Pin 03 - 0v
Pin 04 - 0v
Pin 05 - 3.14v
Pin 06 - 2.47v
Pin 07 - 4.33v
Pin 08 - 4.33v
Pin 09 - 2.53v
Pin 10 - 2v
Pin 11 - 2.54v
Pin 12 - 2.54v
Pin 13 - 2.48v
Pin 14 - 2.5v
Pin 15 - 2.5v
Pin 16 - 2.5v

IC3

Pin 01 - 7.95v
Pin 02 - 0v
Pin 03 - 4.97v

Zener ( D1)

Anode - 0v
Cathode - 0.38v

thank you so much already!

[mcknib]

Try adjusting the 25k trimmer which as far as I am aware is your output volume level it's hard to see but you might have it turned right down so try it the opposite way and if with the advice already given by Rich and Sam you have sorted all your circuit faults hopefully it's just that, that needs adjusted.

The schematic given doesn't correspond with the layout as you've discovered with R5 in the schematic there's an A500K volume control at the output granted outside the shaded area which isn't on the layout so the 25K trimmer must replace it in all of the deep blue delays I've built it's a set and forget volume control.

If it works set it to the same level as your bypassed signal with the advice given your voltages look a lot healthier so as I say here's hoping that's your only remaining problem

and don't get discouraged when it doesn't work and you discover what's wrong you have another eureka moment and learn a lot it's all part of the process

[duck_arse]

your IC1 voltages are still wrong. power off, remove that IC from the socket, and use your continuity meter setting to test between each of the socket pins - look for a 0R or very low. if you don't find one, power on (IC still out) and measure the volts on each socket pin. (also, push the PT2399 DOWN into its socket, it seems not right seated.)

and can we see a photo of the underside of your board?

[PRR]

IC1 pin 8 *has* to be close to 9V (above 7V) or there is no point going further.

IC1 is fed from +9V through R7 to pin 8. Not a lot to go wrong. Trace that trace and find where your "7.95V" is lost.