Fuzz Face Debug

[jlullo]

Hey guys.  Finished boxing up my Fuzz Face from FuzzCentral.
http://fuzzcentral.ssguitar.com/fuzzface.php
http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacelayout.png

Issues:
i can't bias the collector on Q2.  I am using a trimpot per FC's specs, and no matter what way i turn it it makes no change in voltage.  I plugged it in to test anyway and if i hit the strings really hard i'll hear a farty, oscillating noise that will last a second.

I got my trannys from smallbear.  They are 2n1305, and Q1 has a gain of 99, Q2 has a gain of 151.  Everything on the board is stock, and the pedal bypasses correctly.


Q1
C-  -8.05
B- 0
E- 0

Q2
C- -6.44
B- -8.06
E- -6.38


i searched the forum for this problem, and one other person had a similar problem.  He found out that his trannys were in backwards.  I'm sure that these are oriented correctly, and are in sockets.

could someone please help with this?

[joegagan]

i would suggest getting q1 to bias correctly,then we can go from there.

It seems like you might have a short bypassing the resistor between your 9 volt hot and collector of q1

is your battery installed correctly?

[jlullo]

it should be.  on those -9v pads i wired the negative end of my battery clip and the other goes to the switch. is this correct?

thanks for your help on this joe!   i appreciate it

[joegagan]

if you are talking about BOTH -9v leads, that is correct. Where is your other battery lead hooked up?

[jlullo]

on the DC jack.  the negative is to the -9v pad on the pcb, and the positive is going to where it's shown in this diagram
http://www.generalguitargadgets.com/diagrams/fuzzface_lo_pp.gif

however, i have the "bottom" lug of the jack (as oriented on that diagram) empty, because i had both pads of the -9v used on the board.  i figured this would just disable the power jack

[joegagan]

are you using the same exact 9v jack as the diagram? if so, why would you make assumptions and leave lugs emtpy when the instructions/diagrams are very clear?

the jack in the diagram takes the batt out of circ when a power plug is inserted

[jlullo]

i'm using everything the same but the bottom lug that is supposed to go to the -9v on the board.  i had made a post about this previously, asking if the way i had it wired would work, and someone said yes, so i went through with it.  How could i wire that bottom lug to the -9v pad on the board if there are only two- one for the battery, and one for the switch?  should i solder a wire from the jack and just mount it on one of the pads that is being used?

[joegagan]

ok, forget what everyone said when you asked questions.
Wire it EXACtlY like the diagram and get back to us.
the answer to your latest question is right there in the diagram

[jlullo]

do you mean rewire the whole setup like in that diagram, or just the dc jack?  i etched a board from fuzz central

[joegagan]

wire everything like the diagrams you posted links to.  i assume that the pcb you etched is the one that is tied to those diagrams, correct?

it works when wired like the diagrams

i understand you are mixing and matching alittle when you added the LED/ 3pdt, but sounded like you had that covered.

[jlullo]

alright.  i attached that bottom lug of the dc jack to one of the -9v pads.  everything else is wired correctly.  still the same problems

[joegagan]

just for giggles, flip your Q1 backwards from the way you have it and take q2 out of its holster

what are your readings on Q1 now?

[jlullo]

C - -12.61
B - 0
E - 0

[joegagan]

ok turn it back around.
back to what i said a few posts ago, there is probably something wrong with the resistor or trace at the collector of Q1
take a resistance reading across that 33k resistor. what is it?

[jlullo]

-16.70

[joegagan]

ok, looks like your power supply is running a little high.
I suggest doing the rest of your testing with a fresh 9v battery til you get a hold on that power situation.

turn your voltmeter to the resistance setting and do the test i mentioned last post.

[jlullo]

ok.  do you mean taking a resistance reading, or the test with the tranny out?

[jlullo]

this might be an insane question, but 2n1305 trannys are PNP, right?  because if not, i'd imagine that's my problem right there.

[Meanderthal]

 Those are PNP. Joe's right, there's no way you should be getting 12 or 16 volt readings in a 9v circuit. Be best to pop in a battery to be sure.

[jlullo]

okay good.  I've been using a battery for readings this whole time.