I'm Guessing I have a Short Somewhere

[turdadactyl]

I just completed a build and I'm getting just a few mV at any point in the circuit, including right at the DC jack.  I put my meter on the actual power supply and I'm getting right around 9V.  I'm guessing the only two possibilities are a bad DC jack or a short somewhere.  Any other thoughts?  Thanks.

[duck_arse]

short or open? disconnect the power supply, and meter the connector for resistance. 0R? and while the power is off, you can meter around the circuit for resistance, between the ground line and the supply line, see what you get.

[antonis]

short or open?

Hell or Heaven.??
(from PS point of view..)

@turdadactyl: As long as actual PS exibits 9V you can forget about short..

[turdadactyl]

@turdadactyl: As long as actual PS exibits 9V you can forget about short..

Can you elaborate on that please?

[wavley]

@turdadactyl: As long as actual PS exibits 9V you can forget about short..

Can you elaborate on that please?

I think he might have misread that.  If your unloaded power supply puts out 9V your power supply is cool, but if you plug the pedal in and it's dragging the 9V down to a few mV right at the DC jack there is a short somewhere in the pedal.  Your PS is good, you don't need to look at that, but your pedal has a short to ground somewhere because power supplies can't supply infinite current so it's being pulled down to a few mV.

[turdadactyl]

Thanks Wavley.  That's exactly the scenario.  Power supply is at 9V.  Every other point in the circuit, including the DC jack itself, is near 0.

[thermionix]

Can you post pics?  Schematic?  Any chance you've got a protection diode in backwards?

[turdadactyl]

short or open? disconnect the power supply, and meter the connector for resistance. 0R? and while the power is off, you can meter around the circuit for resistance, between the ground line and the supply line, see what you get.

I did find one section that has 0R.  Everywhere else has resistance of anywhere from 18K to 50K.

[GibsonGM]

If your power supply is putting out 9V WHILE POWERING THE CIRCUIT, you don't have a short to ground.  That's what Antonis is saying.    Yes, if you plug it in and it "goes away", you probably have a short (Wavley).

If you have "one section" that shows no resistance from + to -, that is a short.  Fix it, then measure the resistance again.....I am a bit suspicious tho....wiht no power applied, or even plugged in....you should be able to put your black probe on gnd and red probe right on the DC jack where power will come in, and if you did have a 0R place, that should override the other resistances you measured....know what I mean?

Can you run this off a battery?  Odds are that the DC jack is wired wrong, IMHO.

[anotherjim]

It is possible to have 9v from psu when plugged in and 0v on the circuit. Problem is it's hard to directly measure the psu plug (if moulded on) when it's in the socket. 
Scenarios' could be...
Centre pin diameter mismatch - it isn't actually making contact 'cause the socket centre pin is too small for the plug.
A 3 pin DC socket and you've used the switched battery contact for circuit +9v.

[turdadactyl]

Thanks for all the input guys. I'm starting to see voltage in the circuit but still have issues. Therefore I diagnose the problem as likely to be crappy soldering on my part. Looking for more issues...to be continued.

[duck_arse]

a short on the power supply somewhere will result in heat, the PSU, the battery, a series R//C resistor, a copper track, a reverse shunt diode pt in backwards. if no volts AND no heat, the volts aren't reaching the pedal, something is open.