DoD 250 short circuit problem, output jack...

Started by guitar.a, May 14, 2023, 12:34:20 PM

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guitar.a

Okay, I don't quite understand what you're talking about... So that's the real problem?  :icon_surprised: How to solve it? ???

antonis

Quote from: guitar.a on May 15, 2023, 02:25:59 PM
Okay, I don't quite understand what you're talking about...

They are talking about the reason for grounded output.. :icon_wink:

Just desolder output wire from ring and solder it on the tip..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Govmnt_Lacky

Quote from: guitar.a on May 15, 2023, 02:25:59 PM
Okay, I don't quite understand what you're talking about... So that's the real problem?  :icon_surprised: How to solve it? ???

Plug a cable into the Input jack. Use your multimeter to measure from the tip of the cable jack to the Input lug on the stomp switch. Then, measure from the sleeve of the cable jack to GND.

Next, plug the cable into the Output jack and do the same.

I believe duck and antonis (as well as myself) are correct and you will need to move a wire on the jack and re-solder it.
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duck_arse

mmmm, I dunno about that. both jacks, to my eyes, looks to have a tip connection. one has ground via sleeve, the other has ground via ring. so either I'm seeing wrong, OP is using stereo cable, or jack wiring isn't the problem. someone confirm this for me, please.

pardon please, guitar.a, as we talk over you. you are OP, original poster.

ahhh, I see - what my abover post should have read is - the jack on the left is wired tip and sleeve, the jack on the right is wired tip and ring. [going by ordinary tayda jacks.]
don't make me draw another line.

GibsonGM

Just for background....'tip' carries the signal, your guitar cable tip hits this contact of the jack.  On an open jack you can insert the plug and see this in action.   The signal ground of your cable connects to the jack sleeve, also called shield.  That's the barrel behind the tip on a guitar cable plug.   

There is a 3rd contact in a stereo jack called the ring, which is switched by your  MONO guitar cable when plugged in (it shorts shield and ring together, making contact w/the battery ground).   If you had a stereo cable plugged in, it would just contact the 3rd section of the barrel, but that isn't part of this. 

In this scheme, your output jack only uses the sleeve/shield for its ground.

What they're saying is that you have your jack tabs mixed up, your 'tip' connection is going to ground, killing your signal!   
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guitar.a

Hmm... I find it interesting that I tested both jacks like that.  And when it is not connected to the pot, it happens that it is not short-circuited.  When I connect the pot and unscrew it, it immediately short circuit.  Although I am not impressed with these jacks, I will buy others and replace them and test your advice.  Thank you. :)

GibsonGM

Rest assured that all of us have had these problems, guitar.a  :)  In time you learn how to identify what's going on, usually pretty quickly.  This is how you learn.  The key is usually to go back over the circuit very carefully, many times, making sure all connections are correct and that all the part values are as they should be.

The jack wiring may not be your entire problem, but others have noted that there IS a problem with the wiring so it should be corrected. 

How do you know for sure there is a SHORT CIRCUIT?  A short is a path to ground (usually) that should not be there.  When it is happening, if you remove power, you should read continuity from your signal path to ground at or near this point. Or the resistance of the pot, which would change as you turn it.

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duck_arse

guitar.a - please, PLEASE, provide us with THE CIRCUIT DIAGRAM you used to build the box - the whole diagram, even if you have to draw it yourself. we need to see how you are thinking the pot [and the diodes] connects to the world around it. I have a feeling you are misunderstanding or mistranslating something when connecting the pots and diodes and grounds.
don't make me draw another line.

guitar.a

I posted the same in one of the previous answers, I think.  Here is again.  I used this one.  Thanks again, I really want this pedal to work, and you're right when you say mistakes and problems are lessons learned and experience gained!  Can you tell me how I can test the schematic itself that I connected, without any pots, without any jacks connected... :D


antonis

This is not a schematic.. :icon_wink:
(it's a board layout ..)

And pardon me but your build isn't in consistency with that layout..

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

andy-h-h

Quote from: guitar.a on May 17, 2023, 01:57:27 PM
I posted the same in one of the previous answers, I think.  Here is again.  I used this one.  Thanks again, I really want this pedal to work, and you're right when you say mistakes and problems are lessons learned and experience gained!  Can you tell me how I can test the schematic itself that I connected, without any pots, without any jacks connected... :D


Something along these lines;

Step 1:  build an audio probe (google it / search the forum)
Step 2:  unsolder the volume pot from the circuit board, ideally remove the board from the enclosure and switching
Step 3:  with signal running into the circuit, place the audio probe on the output of the opamp (pin 6) - should get a massive signal
Step 4:  place the audio probe on the wire from the board that would normally connect to lug 3 of the volume pot - should get a large signal, but not so much as straight off the opamp
Step5:  reattach the volume pot, now try testing from lug 2

Suggest that if you have a multimeter, you learn how to use the continuity test function, as this will help find / ruleout any suspected shorts

guitar.a

Thanks everyone for the advice.  I solved the problem, don't mind, I don't get to the forum much because of my obligations.  Greeting! :)

antonis

Quote from: guitar.a on May 23, 2023, 01:04:51 PM
I solved the problem, don't mind

But we DO mind..!! :icon_wink:

Wε all like to know both the problem and the solution..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..