Mangler no effect [SOLVED]

[murdog47]

Works fine on bypass but no effect. Had to walk away from it last night before it went out the window. Anyone see anything off the bat that doesn't look right?

[gtr2]

Is this in a testing rig?  Or wired up to a switch and jacks?  Voltages at the transistors?

The parts look ok but other info would help.

Josh

[oldhousescott]

What transistors did you use (can't make them out from the picture)? Are you sure you got the power supply wiring correct for this positive ground effect?

[murdog47]

It's wired up to a switch and jacks, the transistors are a matched American set from Smallbear, triple checked the wiring, not sure how to check the voltage at the transistors 

[gtr2]

Can you take a pic of the switch and wiring to the jacks.  To check voltages put black probe on your power jack ground and red on a leg of the transistor.  Also make sure you are getting -9 at the -9V pad.

Also...this may sound silly but...  make sure the guitar is plugged to the in jack and the out is to the amp.  This is easy to mix up when unboxed and provides sound when bypassed and no sound when effect is engaged.

Josh

[murdog47]

So I'm a little confused with this being a positive ground effect. If I put the black probe to ground and the red to the transistor legs, I'm reading 8.88 on all of them. The build instructions say to use red to ground and black to the test point. When I do this I get 0.00 for a reading.  Here are some pictures of how I have this set up.  The alligator clips are just holding a ground wire between input and output.  The gold tipped cable is coming from my guitar and the black cable is running to the amp.

[gtr2]

You have the power wired incorrectly.  When you place the red tip on the -9 pad and the black probe on the gnd pad you should read around -9V.  You should not be reading a positive voltage.  You are reading 0 on the test point because the circuit is not being powered properly.

It's hard for me to tell but it looks like you have the red power wire on the tip lug of the jack.  Either that or the input wire is on the wrong lug for tip.

Recheck your wiring against the build doc and make sure you have the correct lugs for tip, ring, and sleeve on the input jack.

Josh

[murdog47]

Here is a closeup of the input jack. I think I have it correct? I feel silly, I've never had this problem before. The red wire is the + from the battery snap, the lug with 2 wires is ground and lugs 4 7 and 8, and the single wire runs across lugs 2 and 9 on the 3pdt. As far as I can tell this is correct.

[oldhousescott]

It's the wrong kind of jack. You have a shorting jack and what you need is a stereo jack.

[gtr2]

Also,

I can't tell from the board picture but the black wire from the battery should be going to -9 and the purple ground wire should be going to GND.

Josh

[murdog47]

Yep thats correct.

[murdog47]

Crap what is a shorting jack

[murdog47]

So I switched the input jack, appears I ordered a batch of the wrong ones. Now I have no bypass and when I check the voltage at the test point it jumps all over.  I'm also getting a pulsing noise when the effect is engaged. On DMM black to ground and red to -9v pad gives me -9v.

[oldhousescott]

Shorting jacks are used on the inputs to amps. With no cable plugged in, they short the tip to ground to reduce noise.

[murdog47]

So my main problem was the shorting jack (Thank you oldhousescott!) . After switching to the correct stereo jack I rushed and wired the ground and input backwards. After staring for 30 minutes I realized I was a bone head.  It's now working properly and biased. Thanks everyone for your help. It's nice to make mistakes so I can learn more about the hobby instead of just plugging away.