Thermally burned resistor at 9v DC jack...

[GibsonGM]

Consider me chastised, IvIark.  Gee, after 10 years in here, finally I see the light...carry on.

[canman]

Wow, I didn't realize this would turn into an anti-vero thread, haha!

So back to the matter at hand...I disconnected the output wire from the 3PDT switch (that goes to the output jack) and I connected a cap to the end of it and I've been using that as a probe.  When I probe all the pins of the IC's, I get nothing.  The only time I get sound is when I probe the bottom right corner of the 3PDT switch.  Any ideas?

HUGE EDIT...turns out I had the cable from the amp plugged into the input jack...so now when I probe, I get high pitched squealing just about everywhere I probe...I've never been more confused in my life, I think.

[IvIark]

I'm not convinced this is your best debug tool if you're getting sound at the end because I don't think you'll lose the signal anywhere.  But if you want to try it you need to use the probe to see where you lose signal, so you go from the beginning of the main signal path to the end:

Input wire
1K
220n
Pin 5 of IC1
Pin 7 of IC1
10K
33n
Pin 3 of IC1
Pin 1 of IC1
Gain 2
Gain 3
1u
10K
Pin 9 of IC1
Pin 8 of IC1
220n
1K
47K
1u
Pin 13 of IC1
Pin 14 of IC1
1u
1K
Treble 2
470K
1u
Pin 3 of IC2
Pin 1 of IC2
1n
Pin 6 of IC2
Pin 7 of IC2
1u
10K
Volume 3

Before you do this though, measure the DC voltage between all IC pins and ground.  That may give a big clue where you should focus your attention.

[canman]

OK I'll measure the voltages of the IC pins in a little while, I'm taking a break from staring at this circuit...it's starting to drive me crazy 

Thanks again for all the help everyone.  This is a rad forum, regardless of who likes vero and who prefers schematics!

[canman]

Here are the voltages I'm getting:

TL074:
1: 4.42
2: 4.42
3: 2.98
4: 8.92
5: 2.98
6: 4.42
7: 4.42
8: 4.42
9: 4.42
10: 4.40
11: 0.01
12: 4.40
13: 4.41
14: 4.55

TL072
1: 4.42
2: 4.42
3: 2.98
4: 0.01
5: 4.40
6: 4.42
7: 0.01
8: 0.01

I have no idea if those are the voltages I'm supposed to be getting...it seems like I've got a lot of 4.4ish volts going on...

[nocentelli]

4.4v is fine, it's vref or half the supply voltage, and at a glance appears to be where it should be. The one voltage that sticks out is pin 8 of the TL072 dual opamp which should be supply voltage. (i.e. 8.92v like on pin 4 of the TL074): Check your pin 8 power connection via that long jumper that passes between the legs of the 100n cap just below the dual opamp.

[IvIark]

Yes pin 8 of the TL072 is definitely a problem because that's the supply pin for that opamp, also I would expect pin 7 to be something closer to 4.5V.  Pin 8 is attached to pin 4 of IC2 via 2 solid links, so if you're getting a different voltage at both those points it suggests a problem with one of those links.

[canman]

OK I'm looking at those links right now, particularly the one that goes under the 100n cap right under the TL072, but I'm not sure what exactly to check.  It follows the layout exactly...I've checked for continuity, there doesn't seem to be a bad solder joint, but that's the extent of my debugging knowledge haha!  Could it be a bad opamp?  I know that's pretty unlikely, I guess I'll throw a new one in there and see what kind of voltages I get.

[canman]

Update...for whatever reason, I pulled out the IC and put it back in, and now I'm getting the voltages you guys are saying I should be getting.  So the links are fine, but I'm still getting weak sound/oscillation...  

Also, upon further inspection, it seems like the Treble pot has something to do with the squeal.  When it's all the way to the left, it's a lower pitched squeal, then in the middle, it seems to go away, and when it's up all the way it's a higher pitched squeal.

[canman]

I found a schematic for the TW!  I dunno if I'm allowed to post it or not, I did a google image search and this popped up...

http://3.bp.blogspot.com/-NUlKC9gloDQ/TxL3rucGxdI/AAAAAAAAAjY/CWne3xV_0-k/s1600/wampler_triple_wreck.gif

I'm finding it's easy enough to follow the schematic on the vero layout, but I don't see how the schematic would help locate any oscillation.  Ideas?