Pulling my hair out with a board that does not function when wired to box

[Badcircuit]

Hi Guys,
I apologize if this is the inappropriate place to post.  I have one of my boards that I know works.  However, I've put in in the case and no go.  I've checked everything and it all seems okay.

I'm posting photos in case someone sees something.

[soggybag]

Get your multimeter and these:

- measure 9v at the power jack
- measure 9v at 9v in in the PCB
- measure correct voltage at various points on the circuit. For example op-amp power and vref

Check for ground at the input and out put jack tips.

If that's all looking good check the switch and bypass wiring. Measure continuity with your meter:

- in Jack to out jack in bypass
- in jack to board in from the input jack
- board out to out jack

If that's working make the audio probe:

- input tip
- input of circuit
- follow the circuit to various locations where you know there should something collector op-am output etc.

[antonis]

I'm curious how OP could manage all the above measurements outside a closed case, Mitchell..

@Bad circuit: Are your IN-OUT jacks isolated..??

[Kevin Mitchell]

You've come to the right place. However we're missing a great amount of context.
DEBUGGING - What to do when it doesn't work

[DIY Bass]

It is unusual to see more than 2 wires to the output jack and 3 to the input.  Where are your wires going?

[GibsonGM]

Hi, WELCOME, and this IS the place to post that question

Can you post a link to the build documents you have for this whatever? From the manufacturer if available.  ("what is it?")

Go here and get the offboard wiring PDF for your files, it may help!  http://www.tonepad.com/project.asp?id=35

Do you understand how your jacks work, as in which tab does what?  So, does it work if NOT in the enclosure, including the jacks, switch and all?  If that's the case something is probably touching the case where it shouldn't and shorting the board or something.  If it doesn't work after adding jacks it may be that you have 'tip' misconnected to a ground, perhaps. A grounded input = no sound.

I test all builds with jumpers before adding any bypass switches or jacks so I know the PCB is ok, then any resulting problem will be jack connections or board grounding! 

[duck_arse]

It is unusual to see more than 2 wires to the output jack and 3 to the input.  Where are your wires going?

this jack is miswired. the green wire is on the sleeve. the black is on the ring switch contact. the orange/yellow is on the tip switch contact. two wires makes no sense, either, indicates a mistake upstream. the problem is the switched contacts - inserting a plug leaves both those contacts open circuit, connecting to precisely nothing.

as said, the other jack can have many wires to the sleeve for groundings, but two wires to [maybe, possibly] the tip lug indicates wrongness somewhere. mind - this is all geusswork and conjecture when we have no circuit to compare to. etc.

[Badcircuit]

Hi Guys,

The second wires to the jack is for a true bypass switch.  I've diagrammed out the current wiring.  Please know my wire colors do not correspond to any standard; nor, do the wire colors correlate to the ones in the photos.  I just wanted to make every wire a distinct color.  I appreciate the help.  Thank you.
https://postimg.cc/N99VPwK2

[Badcircuit]

PS:  I have power at the Power Jack but not at the board at all.
Thank you.

[GibsonGM]

Check that battery is not dead or clip is not broken.

If power at jack and not board, reverse red wires on DC jack, then measure again at board.


If it still doesn't work WITH power at the board, go back to the PDF I posted above and redo all your switch wiring. The 3PDT switch that is shown in your drawing IS the true bypass, I don't understand the 2nd switch marked "Bypass" in your drawing......

[Badcircuit]

Gibson,
I did not know that the foot switch would function as a true bypass so I put the second switch in.  An on/on wired to shuttle the signal to and from the board.  I had read that foot switches were not a form of true bypass.  So I take it that information was incorrect.

I will rewire everything and try it again.  I also will try the reversing of the battery workers.  The batter is not dead and I have power at the jack but not anywhere else.

I know the board works as I have hooked it up straight to a battery with two jacks during board testing.

Thank you for your continued help with this problem

[aron]

Yeah, there's an extra switch in there. The one on the right.

[Badcircuit]

The extra switch was intended to be a true bypass switch.  A DPDT on/on wired to either channel the signal through the board or not through the board.

[soggybag]

If there’s no power that needs to addressed.

Use your meter to check each of the three pins on the power jack till you find 9v. You won’t get battery power unless there is plug in the input jack.

Once you get power at the jack follow that wire too. The PCB and check power there.

If that checks out and there’s still no no power at various locations on the board follow the traces closely node by node. If there’s a short you might measure continuity from power to ground! You can check for that as a sanity check.

[GibsonGM]

This has always helped me

http://www.tonepad.com/project.asp?id=35

[duck_arse]

.... second thoughted.

[duck_arse]

It is unusual to see more than 2 wires to the output jack and 3 to the input.  Where are your wires going?

this jack is miswired. the green wire is on the sleeve. the black is on the ring switch contact. the orange/yellow is on the tip switch contact. two wires makes no sense, either, indicates a mistake upstream. the problem is the switched contacts - inserting a plug leaves both those contacts open circuit, connecting to precisely nothing.

as said, the other jack can have many wires to the sleeve for groundings, but two wires to [maybe, possibly] the tip lug indicates wrongness somewhere. mind - this is all geusswork and conjecture when we have no circuit to compare to. etc.

no, no - now I've looked again at the linked wiring diagram - and third thoughted - I think it is intended to switch the supply thru the ring/sleeve when a jackplug is inserted into the jack.

and, so, I say you will never get supply to the board while that jack socket is wired as photo shown, because when the jackplug inserts, nothing connects, ground is not continuous with suppy. hence, no volts. ever. rewire the jack, delete the second switch, try again.

[Badcircuit]

I will do so today. Thank you!

[Badcircuit]

Okay,
I fixed the input jack so the tip, ring and sleeve are now attached to the correct lugs.  I removed the true bypass switch.  And still, no power at the board.

I noticed the battery gets warm.

I know the board works when directly connected to the jacks and the battery.  I've read the literature and did not see anything about the board getting warm.

This is a Valvecaster.  I have had the tube directly connected outside of the pedal and the board worked fine but it was again, straight connected to the battery and the two jacks.

I hate to bother you guys with this.  I'm very adept with guitar harness wiring and I've built pedals before.

It is driving me mad.  I have checked everything 10x.  Traced every wire to the boxing diagram I have, which I know is right because I've built pedals off of it before.

I'm hoping one of you can diagnose from the battery getting warm.

Thank you again, I'm sorry to be such a pest.

[Badcircuit]

EDIT:  I made a typo, the board does not get warm, just the battery.  The board has no power at it.