Terrible volume loss

[Deep Blue]

I built a DOD 440 EF, and bypass mode works, but when I switch to effect mode, I only get an extremely faint signal.  If I crank my amp to like 6 (usually unbearably loud), I can just make out a very distorted and funky signal.

I've stared at the PCB forever, and all the resistors are the right value, all of the capacitors are right, the IC chip works when I plug it into other pedals, the diodes are correctly placed, the soldering is immaculate.  I also followed every single wire, and they all go where they should.  There aren't any shorts or anything..

Anyone know of any likely culprits?  I already randomly relaced almost all of the parts on the circuit board (resistors, caps, diodes) with no effect.

[petemoore]

Did you try audio probing?

[Deep Blue]

I've tried before, but I can never get audio probing to work.

[u1061810]

You probably tried this, but how about  the switch.

[punkaled]

I've been having the exact same problem, until i tried a different guitar, and that worked fine, you sure the problem is the effect  ? does the guitar work with other effects, or the effect work with other guitars?

[petemoore]

The probe is simply a connection to the amp which can be tapped to any point in the circtuit.
 Test that you have a live cable by touching your thumb to the tip and sleeve..you should hear a slight buzz or buzz if the amp is turned up a little.
 Connect the sleeve to ground [I like to use a two ended wire with alligator clips on either end].
 Connect the tip [I like to use a wire with alligators on the ends] through a DC blocking capacitor [just clip it on] and poke away at the circuit [I try to stay away from V+ directly].
 Now with the probe active..you should hear sound if any signal is at the 'tip' connection, start at the probe and listen, then at where the guitar connects to the input [jack or switch usually...I add these later so]..the DC blocking [input cap] at the left side of the circtuit..follow the signal path through the circuit, when you hear a drop in volume or gating, no signal etc. that's the proximity in which to focus your other debugging skills.
 The value of cap you use for the 'tip' connection of the AP can be anything from .01uf to 10uf, actually .001uf to 100uf... but .1uf to 1.uf are more common coupling cap values....  .001uf will cut ALot of Bass so not really recommended for Audio Probe use.

[jimbob]

ISnt there a pic of this somewhere? I know im better with pics.

[niftydog]

http://www.diystompboxes.com/pedals/debug.html

link on this page to a picture.