axis wah

clamup1 · January 23, 2011, 08:54:42 AM

zombiewolf- oh no im going to try to get as vintage as i can. i broke out a SRV album i have and heard voodoo child. i got motivated to try to get my wah to work.

can anyone look at the pcb layout and see if there is a electrical mistake somewhere that wont let it work? im gonna make the buffer this afternoon and watch football. great combo lol

Gus · January 23, 2011, 09:07:48 AM

Did the wha work at one time?

All the transistor pins measure about 9VDC? Did you measure with a plug in the input jack? Where was the neg DMM probe placed? (case? ground trace on the PCB, neg of the battery?)

I would check for a missing ground(s) connection, a DMM has high input resistance so it does not load down the circuit that much. I would start at the input jack

disconnect the battery
set the DMM to Ohms insert a plug in the the input jack to complete the ground circuit
Check all the ground nodes to make sure they are all connected

clamup1 · January 23, 2011, 01:30:15 PM

i had the neg attached to the pin the neg from batt attaches. yeah it worked with the original board. i did something to it and it quit working. so i made this one. im hoping the wah pot or what ever the thing on the left side of the board is, didnt fry or quit working.

Gus · January 23, 2011, 01:42:46 PM

Clamup1

Did you check the connections and read what I posted? You only gave one answer. If you checked at the - battery without a input jack to connect the ring and sleeve you could get readings like you posted.

I posted things to check it reads like a possible open ground to start

Does it pass signal in bypass?

Also I checked the link at the bottom of your posts.
https://sites.google.com/site/garagebandeffects/

I saw payment, you build for money?

kristopher612 · January 23, 2011, 04:14:50 PM

Q1
E.05
B.63
C4.38

Q2
E3.58
B3.99
C8.12
Voltage after the 1K resistor in line with the 9V path is 8.49V with 9.4V coming in from my power supply.
from my functional modded crybaby, should be close to this for working voltages. when i say your 9V wire isn't insulated, i mean i see a piece of cardboard between the wah shell and board in one place, but your 9V wire isn't insulated, so it could be grounding out on the enclosure. try to get the circuit working outside of the wah shell to isolate this type of problem.

clamup1 · January 23, 2011, 06:30:51 PM

@gus- i havent checked the ohm thing yet. do you put the neg probe on a neg ground area? and probe the other ground points with the pos?
i would like to start building for money. i havnt done any kind of advertizing other than the sig on the bottom of my posts. as far as i know there isnt anyone within a 50 miles of where i live that do this so i should do pretty good. except for wah pedals that are aggrivating as hell

@kris- im getting almost the same +pos # on the ground. the only thing i can think of is a bad resistor or cap. there are two res and a cap going to ground.

ill check the ohm thing and see what i get.

kristopher612 · January 23, 2011, 06:44:53 PM

Quote@kris- im getting almost the same +pos # on the ground. the only thing i can think of is a bad resistor or cap. there are two res and a cap going to ground.

that and check with a meter for no other possible bridges. it can be hard to spot them sometimes. i spent 2 days trying to figure out why my tremulus lune had fluctuating power instead of a solid 9v reading, then i saw a wire from the LFO touching something it shouldn't have...just sayin'.

clamup1 · January 23, 2011, 09:04:21 PM

this must be the April Fools wah. im getting + in the ground and there is no way. there are no solder bridges and nothing is touching. it might make better target practice than a wah

kristopher612 · January 23, 2011, 09:11:34 PM

then i would start checking all of your resistor values with a meter, double check cap values, and pull out my hair while i cussed loudly in my garage!

clamup1 · January 24, 2011, 09:33:52 AM

lol sorry.

i changed out the resistors and the 4.7uf cap going to ground.

clamup1 · January 24, 2011, 07:44:34 PM

im gonna rewire all the grounds and see what that does. if there is a bridge its miniscule and cant be seen with the naked eye.

@gus- i was getting almost the same values with the jack in. i need some assistance with measuring Ohms. do you put the neg term on the ground of the pcb and probe the rest of the grounds with the pos probe?

@Kris- i pulled hair and cussed, hopefully i dont have any bald spots lol

kristopher612 · January 24, 2011, 08:16:49 PM

Quote@gus- i was getting almost the same values with the jack in. i need some assistance with measuring Ohms. do you put the neg term on the ground of the pcb and probe the rest of the grounds with the pos probe?

put one probe on a known ground, then make sure all your other grounds are connected using the resistance part of your meter. should be 0 ohms between all your ground connections.

clamup1 · January 25, 2011, 09:31:37 AM

ive got 15ohm. so i have an open ground somewhere right?

clamup1 · January 25, 2011, 09:28:44 PM

i resolderd all my grounds and at one point i got the resistance down to 10. then scrapped the board with a exacto knife and now its back to 15. i dont know how that works

News:

axis wah