fuzz working intermittenly. what gives?

[ode2no1]

ugh...i hate to ask for help on this since it's a fuzz face...but this is totally bizarre. basically the pedal keep going from completely normal (and actually probably the best fuzz face i've ever played) to either complete static or no sound at all. i can't pinpoint what the problem is though. seems like a bad connection or something but by poking around i'm not finding the source. even just tapping on the enclosure will take it in and out of this state. i've wiggled all of the offboard wires and it doesn't seem to be any of them. i did notice though that when it goes into this state the emitter of Q2 goes from being biased around 5v to .962v. any ideas? i thought it might be the input jack but wiggling the guitar cord would only help sometimes.

[LucifersTrip]

ugh...i hate to ask for help on this since it's a fuzz face...but this is totally bizarre. basically the pedal keep going from completely normal (and actually probably the best fuzz face i've ever played) to either complete static or no sound at all. i can't pinpoint what the problem is though. seems like a bad connection or something but by poking around i'm not finding the source. even just tapping on the enclosure will take it in and out of this state. i've wiggled all of the offboard wires and it doesn't seem to be any of them. i did notice though that when it goes into this state the emitter of Q2 goes from being biased around 5v to .962v. any ideas? i thought it might be the input jack but wiggling the guitar cord would only help sometimes.

since you didn't give much info, only the obvious can be guessed: a bad joint or a point that is intermittently being grounded/shorted (ie, touching something it's not supposed to).

I would take full voltage readings as in the debug thread and use an audio probe, while in the not working stage

Of course, you can always re-flow each joint and make sure the board/jacks are not accidentally pressing against something.

[R.G.]

ugh...i hate to ask for help on this since it's a fuzz face...but this is totally bizarre. basically the pedal keep going from completely normal (and actually probably the best fuzz face i've ever played) to either complete static or no sound at all. i can't pinpoint what the problem is though. seems like a bad connection or something but by poking around i'm not finding the source. even just tapping on the enclosure will take it in and out of this state. i've wiggled all of the offboard wires and it doesn't seem to be any of them. i did notice though that when it goes into this state the emitter of Q2 goes from being biased around 5v to .962v. any ideas? i thought it might be the input jack but wiggling the guitar cord would only help sometimes.

It's intermittent because there is an intermittent contact. Sadly, it may be any contact or wire in the circuit. Any.

On a side note, if the wiggling the input cord *ever* affects it, then the wiggling is related to the intermittency some how. What moves when you wiggle the input cord is having some kind of effect. Start watching when you wiggle the input cord.

[ode2no1]

as far as the debug thread here we go:

1 - i'm getting a bypass signal. zero when i turn it on. at first it was just this wall of noise, then would kick on and sounded great...then noise...then nothing. i noticed that even slightly tilting the effect while holding it in my hand was making it cut in and out. then i tapped the case on the ground a few times and it cut out completely and i haven't been able to get signal since.

2 - fuzz face

3 -


4 - no modifications

5 - no parts substitutions

6 - positive ground. no conversion

7 - battery out of circuit 9.48v.
     voltage at circuit black lead 9.28v
     voltage at red lead 0v
     Q1
     C = 1.13v
     B = .934v
     E = 0v

     Q2
     C= .962v
     B= 1.13v
     E= .943v

     C1
     + = 107.5mv
     - = .934v

     C2
     + = 0v
     - = .943v

i ended up bypassing the switch to see if that was the problem, but it wasn't. the strange thing is that the collector and emitter of Q2 are so close when it isn't working, but when it would slip back into working it was biased at about 5v.

[ode2no1]

i also noticed that no signal is on the input jack when i switch the effect on. i can touch the output jack and effect output with my finger and hear a buzz. i can touch the input jack when the effect is bypassed and hear a buzz...just nothing when it's "on."

[LucifersTrip]

    Q1
    C = 1.13v
    B = .934v
    E = 0v

    Q2
    C= .962v
    B= 1.13v
    E= .943v

the strange thing is that the collector and emitter of Q2 are so close when it isn't working, but when it would slip back into working it was biased at about 5v.

do the voltages on Q1 change when it is working?

have you tried removing the circuit from the box to see if it was somehow shorted?

if you have the transistors socketed, did you re-measure them to make sure one or both haven't been blown?