Author Topic: Problem with Dirtbaby - no wet signal (SOLVED)  (Read 382 times)

Longer713

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Problem with Dirtbaby - no wet signal (SOLVED)
« on: November 13, 2017, 07:10:03 AM »
Hi guys!

After some time fighting by myself to debugg this project I gave up and I kindly ask you for help. Although it's my second time building Dirtbaby it never started at first kick. Always something to check..

Problem I have this time is that effects seems to not do much. I get a clean signal through, pots kinda works but they only modulated clock noise, no wet signal at all.

Voltages are fine, except IC4:

1- 8,14V (doc: 4,24V)
2- 0,4V (doc: 4,24V)
3- 3,76V (doc: 3,9V)
4- 0V (doc: 0V)
5- 8,12V (doc: 4,23V)
6- 8,13V doc: 4,24V)
7- 8,14V (doc: 4,24V)
8- 8,68V (doc: 8,89V)

I wanted to check circuit with audio probe but have no idea which pins need to be checked.

Thank you so much in advance for your time and help! :)
« Last Edit: January 10, 2018, 11:32:08 AM by Longer713 »
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madbean

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Re: Problem with Dirtbaby - no wet signal
« Reply #1 on: November 13, 2017, 07:19:26 AM »
IC4 is obviously a big problem here but whether or not that's a bad chip or a solder joint problem is something you need to look at. It looks like you have correct bias voltage at pin3, but from there it goes out of whack.

First I'd start by pulling that IC out, and audio probe pin3 of IC4 (in the bare socket). That will confirm whether or not you have delay coming out of the PT2399. Assuming you do, you need to either swap in a new IC4 or look for problems with your soldering or micro-bridges between solder joints.
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Longer713

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Re: Problem with Dirtbaby - no wet signal
« Reply #2 on: November 13, 2017, 08:34:49 AM »
Thank you Brian for quick reply.
I do get delayed signal from Pin3. I swapped this IC to other sockets and it seems to be working there. I checked values of nearby components to IC4 socket and they seem
to be ok as well. It's gonna take loooonger that I thought.. :(
« Last Edit: November 13, 2017, 08:49:37 AM by Longer713 »
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Govmnt_Lacky

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Re: Problem with Dirtbaby - no wet signal
« Reply #3 on: November 13, 2017, 10:32:12 AM »
The fact that you are seeing almost V+ on Pins 5, 6, and 7 tells me that you most likely have the following wrong in order of likliness:

- Bridged traces surrounding Pins 5, 6, 7, and 8.
- A faulty IC socket
- Bad Dual Op Amp IC

Take an Xacto and scrape carefully around ALL of the solder joints of IC4. Use a magnifying glass if need be.

Good Luck
« Last Edit: November 13, 2017, 10:38:28 AM by Govmnt_Lacky »

Govmnt_Lacky

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Re: Problem with Dirtbaby - no wet signal
« Reply #4 on: November 15, 2017, 01:47:26 PM »
Any resolution or progress on this?

Longer713

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Re: Problem with Dirtbaby - no wet signal
« Reply #5 on: November 15, 2017, 02:50:42 PM »
I haven't found so far anything new. I don't have enough patience for it so I'm currently focused on other projects, just finished 4 Current Lovers and Pork barrel is next for tomorrow. But thanks for cheking, I'll surely post some results once I will fix this sucker.
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Longer713

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Re: Problem with Dirtbaby - no wet signal
« Reply #6 on: January 10, 2018, 11:31:49 AM »
I promised to get back to you once it will be ressurected and there she is!
Me and the mad scientist had to rip apart the block.. oh, wrong story.. I asked my friend for help and he discovered after nearly whole day of scanning the entire PCB that there was one tiny crack near one of IC4 lug that goes to R24. Bridged that thing and it's back to life! :)

« Last Edit: January 10, 2018, 11:33:28 AM by Longer713 »
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