Crybaby 95Q automatic, no sound with guitar but with finger

Visualdistortion · Post by **Visualdistortion** » 20 Apr 2020, 15:03

Hi, I've a 95Q wah that is a switchless/automatic wah, you just have to put feet on it to active the wah sound, down position is bypassed and others are with the effects.
My problem: I don't have any sound when i plug a guitar but if i unplug my guitar and touch the input jack tip with my finger, I can hear the sound in both position bypassed and with effect... WTF
I don't find the schematic actually, but is really close to the Dimebag Darell Wah or 535Q, any ideas where is the problem?
Cheers and thanks for the help.

https://postimg.cc/XpwgKpw6

lolbou · Post by **lolbou** » 20 Apr 2020, 19:32

Faulty jack cord?

Visualdistortion · Post by **Visualdistortion** » 20 Apr 2020, 20:49

no no, ahah, jack are cleans, I the pedal itself, I also already changed the inside jack in case of because they was a bit of rust on it, and nothing change, I really don't find where is the problem on this problem.

lolbou · Post by **lolbou** » 20 Apr 2020, 21:03

That was my first guess...

You mention having "sound" in both modes, that would suggest that the two opamps in IC1 are fine. Maybe the first one is blown off? Check voltages?

Visualdistortion · Post by **Visualdistortion** » 21 Apr 2020, 07:49

I tried to solder again some components like the transistors or opamp, and now I don't have sound with my fingers

But when i plug the jack, I can hear the pedal for 3s and it sound like a FUZZ pedal and the sound stop. Only way to get it again, unplug the jack, plug again, fuzz sound for 3 s and stop.

lolbou · Post by **lolbou** » 21 Apr 2020, 08:58

Visualdistortion wrote:Only way to get it again, unplug the jack, plug again, fuzz sound for 3 s and stop.

You've just build yourself a timer! Bravo!

I would try some audioprobing, but you may have a blown opamp in the IC? Now for the 3s stuff, does it happen as well when the pedal is used with a wall wart power supply (sounds like a short to me). Did you feel any hot component while your fingers were inside?

phatt · Post by **phatt** » 21 Apr 2020, 12:03

I would treat that schematic as suspect.

The Notes state to connect pin4 to VEE.
Where the hell is VEE?? Pin 4 is usually VCC, or + input.
there is also a VDD which goes nowhere??
I would go check you have it all wired up right.
The last line on the Notes says "Circuit NOT Tested" so it's anyone's guess if it even works.

Those two I Meg resistors for bias voltage is just plain silly.

Anywhere from 100k or down to 10k would deliver a more stable bias.
Your circuit is likely wired wrong.
If you don't know how to do it I can redraw it so it makes more sense, though there is a chance it still may not work.
cheers, Phil.

Visualdistortion · Post by **Visualdistortion** » 21 Apr 2020, 15:32

lolbou wrote:
Visualdistortion wrote:Only way to get it again, unplug the jack, plug again, fuzz sound for 3 s and stop.
You've just build yourself a timer! Bravo!

I would try some audioprobing, but you may have a blown opamp in the IC? Now for the 3s stuff, does it happen as well when the pedal is used with a wall wart power supply (sounds like a short to me). Did you feel any hot component while your fingers were inside?

Nothing hot, I triple checked everything, but one of the SMD capacitors seems to be little "static" but I don't know where it's on the signal and if it's the normal situation.

I will try audioprobe but with no real schematic and a really compact design, it's not really easy to follow the signal ahah.

https://postimg.cc/XpwgKpw6 This schematic seems more realistic

hogan666 · Post by **hogan666** » 26 Jun 2020, 05:29

I have a similiar problem (see my thread). Resoldered two transistors, the IC. Still no sound. Only fuzz. :/
Did some audioprobing but without a proper schematic & a lot of smd it doesn’t make fun.

Dunlop won‘t send out a schematic too.

Cheers, Markus.