Silicon Fuzz Face issues

Started by FuzzFace_EXP, June 06, 2011, 06:41:47 PM

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FuzzFace_EXP

Hey whats up guys?! I'm building a silicon fuzz face and I'm have a lot problems getting it goin. I've triple checked everything, wiring, cap polarity, transistor pinout and nothing is connected incorrectly. The guitar signal goes by when the effect is not engaged but when i turn on the pedal the fuzz pot does nothing and the volume pot works backwards. Ive built a few fuzz faces and other effects never had to debug one until now. I checked the debuging page and got the transistor voltages if you guys need them let me know. Here's the wiring diagram that i used the only difference is that i used the Iss2 board.

petemoore

  Unless you can figure a way to test current, currently it requires cut/splicing a current meter into the circuit.
   Voltage measurements are much easier and so we're more attune as to what to look for there.
  Although the audio probe is simple, for 9v, when I lost the probe the first time, I use the audio injector technique instead, even simpler, using 1 right thumb as audio source, connected to a probe so it is very easy to touch wherever I want to inject audio [as simple as de-insulating both ends of a solid core wire].
  Starting at the output jack tip is a good start, if nothing here suspect ground may be getting at it somehow.
  Once the bzzz sound is heard, move to switch, through switch, through all that and the wire to the output cap, the output cap [inside the DC circuit], the collector [collector output, otherwise the actives output pin], then, the input should be...what the input should be compared to the output:
  For Q2 of FF, the collector should be a good deal louder than the Base.
   Consult audio probe and reverse...a probe monitors, an injector is a source, they are inverted versions of each other as far as debugging goes, the injector is easier for me to find/make, so I'm used to using that.
  That said, the FF is a 2 transistor feedback loop amplifier circuit, as such there is only so much probing that makes sense for it...mainly for getting audio source to the Q1Base [with no DC riding on it], and audio out of output, once the voltages come into ballpark they work [certain rare or unknown caveats not mentioned.
  Once the in's and out's are correct, yep, it's all really about the voltages.
Convention creates following, following creates convention.

peps1

3 point and you should have a working Fuzz face

1: If your using a issue 2 board, you need to swap the 300 and 33k resistors round. (this is called the peps1 mistake, as I do it myself 90% of the time!)

2: The transistor layout on the iss 2 is also different, on the iss2 its ECB and BCE on iss1 its EBC and CBE.....so change the pins of you transistor accordingly

3: ignore that off board wiring with excessive ground wires, and use this one:




FuzzFace_EXP

Quote from: petemoore on June 06, 2011, 06:57:43 PM
  Unless you can figure a way to test current, currently it requires cut/splicing a current meter into the circuit.
   Voltage measurements are much easier and so we're more attune as to what to look for there.
  Although the audio probe is simple, for 9v, when I lost the probe the first time, I use the audio injector technique instead, even simpler, using 1 right thumb as audio source, connected to a probe so it is very easy to touch wherever I want to inject audio [as simple as de-insulating both ends of a solid core wire].
  Starting at the output jack tip is a good start, if nothing here suspect ground may be getting at it somehow.
  Once the bzzz sound is heard, move to switch, through switch, through all that and the wire to the output cap, the output cap [inside the DC circuit], the collector [collector output, otherwise the actives output pin], then, the input should be...what the input should be compared to the output:
  For Q2 of FF, the collector should be a good deal louder than the Base.
   Consult audio probe and reverse...a probe monitors, an injector is a source, they are inverted versions of each other as far as debugging goes, the injector is easier for me to find/make, so I'm used to using that.
  That said, the FF is a 2 transistor feedback loop amplifier circuit, as such there is only so much probing that makes sense for it...mainly for getting audio source to the Q1Base [with no DC riding on it], and audio out of output, once the voltages come into ballpark they work [certain rare or unknown caveats not mentioned.
  Once the in's and out's are correct, yep, it's all really about the voltages.
These are the volatges i'm getting. Im not sure if im doing it right as its the first time im doing this.

Q1 Emiter 9.03v/Base 9.44v/Collector 9.46v
Q2 Emiter 9.03v/Base 8.99v/ Collector 9.44v

This to me seems completly wrong.
Quote from: peps1 on June 06, 2011, 08:25:33 PM

3 point and you should have a working Fuzz face

1: If your using a issue 2 board, you need to swap the 300 and 33k resistors round. (this is called the peps1 mistake, as I do it myself 90% of the time!)

2: The transistor layout on the iss 2 is also different, on the iss2 its ECB and BCE on iss1 its EBC and CBE.....so change the pins of you transistor accordingly

3: ignore that off board wiring with excessive ground wires, and use this one:




I Checked the the resistors thery are all in there coreect spots. I also checked the transistor pinout, I followed the indications on the bottom of the board witch are the one you mentioned and im still having the problem. That wiring diagram that im using has worked for me on other fuzz faces that ive made. I just follwed wires from the pic of an original thats the only reasone i modified your diagram. Any ohter ideas of what it might be? thanks for the input so far guys!

peps1

Any chance of some photos of both sides of the board?

FuzzFace_EXP

Quote from: peps1 on June 06, 2011, 10:42:22 PM
Any chance of some photos of both sides of the board?
Sure here you go. Its a little messy i know, ill clean it up if it ever works  :icon_lol:




peps1

All seems good on the front and back.......so that leave switch, jacks and pots! (assuming one of the transistors is not duff)

Any chance of a labeled shot of the switch?

(do you have this jumper soldered in?)


FuzzFace_EXP

Yup the jumper is in there.

The red wire on the left side of the switch goes to the first hole on the board that goes to the 2.2uf cap

Green wire on the left side goes to the second hole that goes to the 22uf cap.

The red wire on the left side that's on the same spot as the green wire goes to the 3rd lug of the volume pot looking at it from the back

The black wire on the bottom right goes to tip of the stereo jack i believe

The red wire on right side goes to the tip of the mono jack

The blue wire goes to 2nd lug on the volume pot looking from the back of the pot



peps1

switching seems OK  >:(

Have you double checked for shorts......looks like two doggy spots here

FuzzFace_EXP

Quote from: peps1 on June 07, 2011, 01:57:02 AM
switching seems OK  >:(

Have you double checked for shorts......looks like two doggy spots here

I checked it but it doesn't look like theres a short but just in case i still scratched that section with a blade. I hooked it up and now when the volume pot is at zero this high pitched sound comes out and when i turn the fuzz pot the pitch get higher or lower. ITS DRIVING ME INSANE  :icon_evil: Ive got way 2 lucky with making pedals Ive only made about 10 and never had issues. It was time i had to grinde my teeth on one  :icon_sad:

You think it could be a transistor maybe a cap?

Brymus

#10


But really the problem appears to be shorts, from your voltages.
You have nearly the same voltage on all 6 pins of those two transistors so you know what is wrong.
I'm no EE or even a tech,just a monkey with a soldering iron that can read,and follow instructions. ;D
My now defunct band http://www.facebook.com/TheZedLeppelinExperience

Derringer

did you twist the base and collector leads of each transistor to go B C E ?

did you insulate the transistor leads? are they shorting to each other? shorting to the metal cap of the transistor?

FuzzFace_EXP

Quote from: Brymus on June 07, 2011, 04:43:11 AM


But really the problem appears to be shorts, from your voltages.
You have nearly the same voltage on all 6 pins of those two transistors so you know what is wrong.
Yeah its really weird though. I looked through it all and it doesn't look like theres any shorts anywere. I don't know what to even look for at this point.

FuzzFace_EXP

Quote from: Derringer on June 07, 2011, 06:35:40 AM
did you twist the base and collector leads of each transistor to go B C E ?

did you insulate the transistor leads? are they shorting to each other? shorting to the metal cap of the transistor?
Yup i isolated the transistor leads there definitely not touching. Any ideas on why the volume pot is working backwards if its all wired right?

FuzzFace_EXP

Any one? Still stumped on this one. :icon_frown:


LucifersTrip

Quote from: FuzzFace_EXP on June 07, 2011, 02:18:16 AM
Quote from: peps1 on June 07, 2011, 01:57:02 AM

I checked it but it doesn't look like theres a short but just in case i still scratched that section with a blade. I hooked it up and now when the volume pot is at zero this high pitched sound comes out and when i turn the fuzz pot the pitch get higher or lower.

You think it could be a transistor maybe a cap?

after this change, are the voltages still:
Q1 Emiter 9.03v/Base 9.44v/Collector 9.46v
Q2 Emiter 9.03v/Base 8.99v/ Collector 9.44v

unfortunately, at this point, if you did indeed orient & wire everything correctly, by process of deduction, the highest chances are faulty or shorted joint or bad component
always think outside the box

Derringer

OP - can you check for continuity between your power rail and ground?

slacker

If you've used a stereo jack socket like in the wiring layouts are you plugging a jack in before taking the voltage measurements? Those voltages look like what can happen if you don't.

FuzzFace_EXP

#19
Quote from: Derringer on June 09, 2011, 03:52:43 PM
OP - can you check for continuity between your power rail and ground?
Just to make sure as I'm new to electronics and self taught when you say power rails you mean the traces correct? Form what i interpreted from what you said is. To put one of the test probes to ground and the other on the traces. I'm i right? Sorry for my ignorance  :icon_redface:
Quote from: slacker on June 09, 2011, 03:57:17 PM
If you've used a stereo jack socket like in the wiring layouts are you plugging a jack in before taking the voltage measurements? Those voltages look like what can happen if you don't.
Yup they where pluged in.  Thanks for all the help guys