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Troubleshooting the Doombutter (w/ fuzz lift)

Started by whitebread47, May 16, 2013, 10:15:27 PM

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whitebread47

I rocked this before I boxed it and everything worked fine through my test rig.  Wired it up and now it only works in bypass.  I've quadruple checked my wiring and can't find any problems, but I believe something is going awry at the input.  I don't currently have an audio probe, though I need to make one soon.

The entire right side of the PT2399 reads the exact same (3.58v). 

Here are my voltages:

LM386
1- 1.26   8- 1.26
2- 0.00   7- 4.03
3- 0.00   6- 8.08
4- 0.16   5- 2.89

PT2399
1- 7.18     16- 3.58
2- 3.57     15- 3.58
3- 0.00     14- 3.58
4- 0.00    13- 3.58
5- 3.79    12- 3.58
6- 3.58    11- 3.58
7- 0.50    10- 3.58
8- 0.99     9- 3.58

Reg. L78L05
1- 7.18
2- 0.00
3- 8.08


Pics - I had to desolder the input, ground, and +9v wires to get shots of the solder side of the board:





Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

whitebread47

Bump.  Just seeing if anyone has a working Doombutter and can tell me if those voltages are off - the 3.58 down the whole right side of the PT2399 seems peculiar to me.
Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

wgc

Love the yellow...!

Crazy thought here, but what kind of foam is that under your pcb?  Anti static foam is usually conductive.

Good luck
always the beautiful answer who asks a more beautiful question.
e.e. cummings

whitebread47

It's double-sided 3M tape.  I've used it in a lot of builds, so it's definitely not conductive.  I didn't know that about anti-static foam; thanks for the tip!
Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

jimilee

Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

selfdestroyer

#5
Here is mine


Here is what I got voltage wise:

LM386
1- 1.3     8- 1.32
2- 9.5m   7- 4.4
3- 0.00   6- 8.9
4- 0.16   5- 1.8

PT2399
1- 5.0      16- 2.53
2- 2.53     15- 2.53
3- 0.00     14- 2.53
4- 0.00    13- 2.53
5- 2.86    12- 2.53
6- 3.6   11- 2.53
7- 0.87    10- 2.53
8- 0.97     9- 2.53

Reg. L78L05
1- 5.0
2- 0.00
3- 8.8

hope this helps. I will keep it open so if you need anything else just ask.

Can I ask how you did the fuzz lift on the Doombutter PCB? I have seen it for the vero but I had issues on the etched Doombutter.

Cody

Edit: I just realized I used the older Doombutter build doc and realized the newer V2 has the lift pads on the PCB. lol maybe its time to make another one.

whitebread47

Cody, thanks a ton for posting that picture!  Right off the bat I noticed I have my voltage regulator oriented the opposite way your is.  I hear this can vary from one manufacturer to the next.  Mine's a Fairchild I believe.

My voltages don't seem too off after looking at yours, so I'm thinking either my 7805 reg. is either fried from being backwards or there's some sort of grounding issue with my wiring.

It'll be morning before I can check, but I'll use your pic and go track down the datasheet for my voltage reg. to check the pinout.

While responding I noticed you found the "fuzz lift" version.  That's what I had Haberdasher etch for me - it's an incredibly useful mod on such a wacky pedal.

Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

selfdestroyer

Quote from: whitebread47 on May 17, 2013, 05:06:57 AM
Cody, thanks a ton for posting that picture!  Right off the bat I noticed I have my voltage regulator oriented the opposite way your is.  I hear this can vary from one manufacturer to the next.  Mine's a Fairchild I believe.

My voltages don't seem too off after looking at yours, so I'm thinking either my 7805 reg. is either fried from being backwards or there's some sort of grounding issue with my wiring.

It'll be morning before I can check, but I'll use your pic and go track down the datasheet for my voltage reg. to check the pinout.

While responding I noticed you found the "fuzz lift" version.  That's what I had Haberdasher etch for me - it's an incredibly useful mod on such a wacky pedal.



Not a problem.. It was funny really.. I was cleaning up a bunch of pedals and I actually had it next to me on my desk when I read your post and my DMM was like 2 feet from me also.. so it was destiny. lol

I hope it helps you track it down.

whitebread47

Quote from: selfdestroyer on May 17, 2013, 05:11:50 AM
Not a problem.. It was funny really.. I was cleaning up a bunch of pedals and I actually had it next to me on my desk when I read your post and my DMM was like 2 feet from me also.. so it was destiny. lol

I hope it helps you track it down.

Talk about convenience!

I just took a look at the original Doombutter build doc and the voltage regulator is facing the other way, though the basic layout doesn't seem to be all that different.  All the more reason to check the pinouts I suppose.
Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

ch1naski

Your voltage regulator should be showing 5 volts on the output pin, right?

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one louder.

Haberdasher

If it worked un-boxed, it has to be a wiring issue or something grounding out, right?

Can't see any wiring problems from that pic.  I wonder if one of your pots turned when you tightened it on the outside and is now grounding to the case or hitting up against the lugs of another pot.
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Scruffie

Well your voltage regulator isn't doing its job and your PT2399 is probably dead now, 5V max and it's got 7V on it.

Whether you shorted something boxing or the PT2399 managed to survive for a little while on 7V before popping its clogs I couldn't say.
Works at Lectric-FX

whitebread47

Quote from: Haberdasher on May 17, 2013, 12:24:23 PM
If it worked un-boxed, it has to be a wiring issue or something grounding out, right?

Can't see any wiring problems from that pic.  I wonder if one of your pots turned when you tightened it on the outside and is now grounding to the case or hitting up against the lugs of another pot.

That's a possibility since my drilling left little room.  The pots were in the box when I tested it, so all I did was connect the four test wires directly afterwards - still a chance it's this.

Quote from: Scruffie on May 17, 2013, 12:37:26 PM
Well your voltage regulator isn't doing its job and your PT2399 is probably dead now, 5V max and it's got 7V on it.

Whether you shorted something boxing or the PT2399 managed to survive for a little while on 7V before popping its clogs I couldn't say.

I only tested it for a minute before wiring it to the jacks and switches, so this is possible.  Going to have a look at it now.
Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

whitebread47

Well, I got the Doombutter working now!  I had the voltage reg. oriented the wrong way.  Apparently the ST and Fairchild brand LM78L05's have opposite pinouts.  I'd looked up the wrong brand accidentally, as the brand of 7805's I had consisted of all ST's and one chance Fairchild, so I oriented it right thinking it was a different brand.  ::)

The PT2399 was fried, but now I'm getting 4.99v where needed.  Thanks for the help, guys!
Blake

"I don't think people are looking for the meaning of life as much as they are looking for the experience of being alive." - Joseph Campbell

selfdestroyer