Busted 'Snarling Dogs' wah - got it cheap, now what?!

[ACS]

Hey guys

So I picked myself up a non-functional 'Snarling Dogs' wah on Ebay for about $30.  It's the bass version (the bronze/gold one), but that doesn't bother me too much, as it's going to get 'some' mods anyway   So then, does anyone know much about these?  All I really know is that they are damn expensive to begin with, and this one was worth it for the case alone!!  Is it worth trying to fix the circuit and then mod it to suit guitar?  Or should I just salvage what I can (jacks, pot, inductor - if it uses one ?!?!? ) and build a crybaby clone in to it??

All thoughts, advice and general musings appreciated!

Aidan

[jmasciswannabe]

I'd try to fix it first. I had a friend with one that had a bad input jack. Figured it out by simply taking off the bottom and wiggling parts around while playing it. Open it up and check to see if any wires or disconnected. If it's not something obvious than get the audio probe out and check it starting from input. There's a wicked good thread to follow somewhere called "what to do when it doesn't work." It's great for fixing broken pedals and later fixing diy pedals where you've goofed up somewhere.

[ACS]

Picked it up and woohoo! it (kinda) works!!  Well, that's a start at least  

Seems to be several probs that I can see so far - this wah has three modes - in the normal mode it works fine, although the 'Q' is well off (suspect this is actually normal as it's a bass wah and I'm using my guitar through it!).  In one of the other positions it just makes raceboat-type noises!  Any thoughts on that one??  In the final position it just makes no noise whatsoever...

So, does anyone know where I could get a schem for this?

Thanks
Aidan

[ACS]

No ideas guys?

OK, plan B then.  Having never reverse engineered a PCB back to a schematic, any tips on how to go about this?

[andrew_k]

I think Joe Gagan has a snarling dogs wah, hopefully he'll see this thread soon and be able to offer some advice. In traditional wah circuits the only difference between a bass wah and a guitar wah i s the value of one capacitor; have a search for bass+'wah mods' and you should turn up some useful info.

[ACS]

Thanks mate, I thought that was the case, so it's nice to have that one confirmed!!  Have PM'd Joe as well, so hopefully he can help....

Now, all I need to do it get the sucker running properly! 

Here's a question to bide the time: There are four what look like green caps together on the board, but one of them (the largest) has the designation Q1 on the board.  Thoughts?  A second inductor maybe? - I know some of the SD wahs had two...  Now across all of these is a small to moderate amount of what looks to be dried glue! It's yellowish and elastic - I'd say it looks most like dried contact adhesive, and is just kind of draped across them.  Any ideas??

I'll post some pics of the mystery component and the 'glue' when I get home tonight (slacking off at work at the moment )

Aidan

[joegagan]

i took the easy route!
i sent mine back to kenny segall, the designer. i bought mine sans switches, sent him an email , he quoted a very reasonable price to do a rebuild, couldn't refuse. he is one cool bad ass dude.

i would suggest the usual debugging steps if you wanna figure it out. mine doesn't seem to have the mystery component IIRC

the production quality on these was iffy, don't rule obvious probs as possible.

but i dig em!

[ACS]

Thanks mate - I sent you a PM wondering if you were able to take a couple of pix for my under the hood?  Want to confirm the wiring is all correct first before I start tinkering!!  Any chance of that mate?

btw, had a thought on the 'glue' stuff - what happens when a cap lets go?  Can it spit anythign like this out?

Actually, another thought - I tested the protection diode (or what I assume is the protection diode) in circuit - this gave me a reading of around 20K (I think - will double check tonight) in one direction and open circuit the other... Struck me as wrong, but then I know that components don't read as expected in circuit...  Thoughts on this one?

[joegagan]

the gut shots of mine probably wouldn't help. mine is a mold spore which has a ring modulator built in. lots of extra stuff.

the glue you see is actually probably just that. these people like to use glue in assembling things.

not sure what the diode should read///

[tiges_ tendres]

I think those four caps are probably the different settings on the rotary switch.  My old SD wah had shaft, white room and some hendrix setting, which basicaly add bass/cut treble depending on where the switch is set.  If when you turn the rotary control, it craps out, there is a good chance that its either the caps, the switch or the connection between the switch and the caps.

[ACS]

Excellent!  That's a fantastic bit of advice!  Will check tonight...

Joe, one of the things I'm not certain is correct is the looms from part to part - there's serious evidence of rewiring.  I strongly suspect that these are mostly based off a stock board and connectors/connections, so some pics of your internals might be more help than you think - if you don't mind that is!  Certainly can't hurt...

Thanks guys, getting there! Once it's up and running, then the mods can start 

[ACS]

Well. I'm feeling rather proud of myself at the moment

Pulled it all to bits, figured out a few things.  Like the 'mystery component' was just a normal greencap with a poorly placed Q1 label!!  Second, was looking at the component side, up to the light to see the traces - thought 'hang on, if that's the cap selector switch, what's it doing connected there??'  Sure enough, the previous owner had reversed the connection of two identical jumpers - when I switched them back to what seemed logical to me, I got the eyes on the rocker lighting up for the first time, but the wah still only 'worked' in one switch position, albeit a different one. 

'Hmmn' said I, 'that's odd - looks like it's not the original switch.   Wonder if it's been miswired?'  Sure enough, a bit more sleuthing and I'm 90% sure that the common wire had been put on to one of the switch positions by mistake.  Switch em around, and up fires the other two positions!!

Yeah baby! 

So the caps that are being selected are either: 82n, 12n or 220n (remember this is/was a bass wah).  I had a nose through GEO's 'Technology of the Wah' which seems to me to indicate that a stock guitar wah sits around 10n.  Can someone confirm or deny that?  So then, what are some good values to go for in my three positions then?  Interestingly, the 220n cap basically just gives a volume change - initially I thought that this indicated a failing cap (as per GEO) but I suspect that this is just because the value is far too high to do anything meaningful with a guitar...

So then, to recap:
1. What 3 cap values should I go for?
2. Does the volume change only with the 220n likely indicate another problem?
3. If it's all good, what should my next mod be?!

Cheers for every single bit of help guys - can't say how much I appreciate it