Help with a DOD FX22 debug

[Govmnt_Lacky]

Need an assist. I have a DOD FX22 Vibro Thang that is giving me nothing but static noise on the output. Looked at wiring... no dice. Checked for proper voltages and grounds... all look good. Schematic can be found online pretty easily. Link to schematic added I think 

https://www.dropbox.com/s/bhlvlrxp1mu44tk/FX22.pdf

Here are my voltages:

U1/U2: LM13600 (Numbers in RED are different on U2. All other voltages are same as U1)

1) 1.27
2) 1.10
3) 4.40
4) 4.40
5) 5.58
6) 0
7) 5.58
8] 4.40
9) 4.40 3.23
10) 5.58 4.40
11) 9.5
12) 5.58 4.40
13) 4.40
14) 4.40
15) 1.10
16) 1.27

U4: LM358

1) 2.5 - 5.1
2) 2.5 - 5.1
3) 2.5 - 5.1
4) 0
5) 2.5 - 5.1
6) 2.5 - 5.1
7) 2.5 - 5.1
8] 9.5

So... the voltages all look pretty good to me. My LFO appears to be working. All of these were taken with the effect bypassed and all pots full CCW.

I would audio probe but... I have no idea what to listen for and where to listen for it   Not a lot of experience with these OTAs. Can anyone offer an idea of what to listen for and where?

[Govmnt_Lacky]

Anyone?? Ideas?

[Quackzed]

i must be bad at finding schematics... but i couldn't find one.
could post one?

[Govmnt_Lacky]

(Link to schematic added to original post) 

[Quackzed]

check/probe u2 pin 8 then 9, if good u3 8 then 9 seeif you get anything like what you're putting in...

[Fender3D]

You got static noise in bypass also?
OTAs are not so much different from usual op-amps about signal flow...

What if you short FETs pin 2 and 3 (D and S)? Not Q1 of course...

[Govmnt_Lacky]

Well... it is definitely some kind of grounding issue. When I plug ONLY the output jack into the amp from the pedal (with NO input jack OR power plug inserted) I get terrible humming! This is magnified when I insert the 1Spot power adapter.

Humming is there when the pedal is bypassed AND effect is on. For the life of me I cannot locate the problem though. I might have to start by replacing one jack at a time as all the grounds read good. All power reads good. And, I have no shorts between power and ground.

[Quackzed]

maybee check that output jack for corrosion or wear... maybee residue of spillage?

[Govmnt_Lacky]

maybee check that output jack for corrosion or wear... maybee residue of spillage?

Sooooo close! 

Well... I have always preached it and I finally found a good example of the following:

ALWAYS GROUND BOTH THE INPUT AND OUTPUT JACKS WITH WIRE!!!

Apparently, DOD only thought to ground the Input jack and let the Output be grounded with the chassis. Problem with that is when they painted the enclosures... it prevented the Output jack Sleeve from contacting the enclosure (which I assume happened after the factory quality check due to wear and tear or movement ever so slightly of the jack)

I simply installed a jumper wire from the Input jack sleeve to the Output jack sleeve and VIOLA!!! Works like a champ! 

Another instance of proving why this should be done on every build!

[Quackzed]

awesome!!! much easier than replacing chips!!!
you know, i just remembered my dod milkbox had a kinda similar issue, it worked but was noisy. i forget what made me do it but chipping the paint from around the output jack for better contact made it much less noisy! go figure!