Fuzz Face Debug

[jlullo]

alright, i'm an idiot.  when i was measuring that resistor, i thought you meant you wanted me to put my dmm leads on both ends.  i did it correctly now, and i have a reading of -8.00.  just in case, i swapped out the 1n4001 as well and there is no change on anything.  any suggestions?

[joegagan]

yes, put both leads of the dmm on the resistor, both ends. should read somewhere close to 33k. use the manual from your dmm to set the range for resistance
my guess is a blob on your trace between the q side of the 33k   and the 33k pad, giving you full continuity of the -9v across what is supposed to be a resistor.
continuity means 0 ohms or therabouts.

[rasco22862]

Im using AC188k an i get:

Q1

E: 0v
B: -0.8v
C: -0.11v

Q2

E: -0.07v
B: -0.11v
C: -8.71v

I put a 5k trimmer next to the 8k2 resistor, and adjusting the trimmer, i only reach -8,21v
What should i do?

[jlullo]

alright.  this morning i scrutinized every pad on the board and there are no solder bridges.  everything is as it should be.  i also, just for kicks, resoldered in that resistor to no change.  This leads me to believe that either my wiring is still wrong (most likely) or that these trannys are bad (not likely).

this is how i have this guy wired up.  if you guys see anything weird, please let me know.

Starting with the PCB, i have the following pads
1. going to the input on the switch
2. going to fuzz lug #2 on pot
3. grounds for Fuzz pot  lug#1, Vol pot lug #1, input jack shield, output jack shield
4. 2 -9v dc pads going to switch (where it's labeled -9vdc), and to the negative wire on the battery snap
5. vol pot lug #3
6. fuzz pot lug #3

On the 3PDT, i have it wired exactly like:
http://fuzzcentral.ssguitar.com/faq/switchwiringpnp.gif , with the lug that says -9v going to the board

and the DC jack is wired like this:
http://www.generalguitargadgets.com/diagrams/fuzzface_lo_pp.gif, with the -9v soldered to the other -9v pads on the board.

is there anything that i did wrong here?

[Meanderthal]

 Wait...

2. going to fuzz lug #2 on pot

Do you mean the out from the PCB goes to lug#2?

volume pot
Lug #1 should be wired to ground.
Lug #2 should be wired to the switch lug labled Circuit Output.
Lug #3 should be wired to the out from the PCB.

Man, this one must be drivin' ya nuts...

[jlullo]

i think that is what i mean.  i mean i have the pad labeled as "2" on this diagram going to lug #2 on the fuzz pot:
http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacelayout.png

i also have my volume pot wired up as you said.

this is really driving me nuts.  i don't understand how i ALWAYS have problems with these simpler circuits, and can burn through more complex ones with no problem

[Meanderthal]

 Oh, my mistake, I thought ya meant the vol. pot.

Joe's much more qualified to walk ya thru a debug than I am, you're in good hands! Try to be patient and do what he says, I have no doubt he'll help ya get to the bottom of it.(provided he has the time)

Hang in there man, it happens. I had to start over 3 times to get my first FF working...

[jlullo]

definitely!  i appreciate your help as well, and as usual

[jlullo]

joe,
just as a quick update, i measured that resistor, and it's coming in at right around 30k. 

[petemoore]

  Then think of every way possible to apply the DMM, you probly read the book on it..
  Set to R mode, test every resistance [through connections if possible], no power
  Set to V mode [well you already did that]
  Set to diode test, no power, test all grounds, test both battery supply lines for their connections and non continuity between them, test *this goes where it should and no-where else [pick a node and test from there..schematic is what I use no matter what I'm debugging, try it from the schematic.
  theres's got to be a loose wire or ground.
  I put a 5k trimmer next to the 8k2 resistor, and adjusting the trimmer, i only reach -8,21v
What should i do?
E: 0v
B: -0.8v
C: -0.11v [should be something like 1.15~

Q2

E: -0.07v [not sure what this one should be, check ROG
B: -0.11v [this is connected to Q2c, both are -0.11v, ok
*C: -8.71v [what's battery voltage, this is high, should be ~1/2v.
  I'd get the pinout for sure from data sheet, and observe the polarity of the arrow in the transistor symbol, as well as the EBC pinout.
   

[jlullo]

k, thanks for the response pete.  I'll scour the hell out of it first thing in the morning

[Meanderthal]

 Hey, didja ever get it fired up?

[joegagan]

once we got to 13 0r 14 v out of a 9v battt, i needed  a break

but now i am curious again too
sounded like the multimeter was set wrong...

[jlullo]

hey there guys.  i haven't.  i can't figure out what is wrong... there are no solder bridges, all of the components are the correct size, etc.  i'm convinced it's the wiring.  i don't know what i did incorrectly, though as everyone is saying that it is wired correctly. i'm going to disconnect the dc jack and just wiring in the battery snap to see what happens.  i'll let you guys know

[petemoore]

  I guess the votlages are still off, the collector near V+.
  There's gotta be something in there that's different than the schematic, the DMM can measure, if you socketted you could test the tranny's or swap in good ones [nice to have it working before exposing all your Ge's to it though], but you could test the transistors internal diodes, use a transistor and DMM on diode checker setting, use the leads to find the B/E diode threshold value, reverse the leads and the meter should not respond, all transistors good should produce similar readings.

[jlullo]

pete, i tried other resistors, and the same thing   will someone give me a gun so i can shoot this?

[jlullo]

alright, i disconnected the dc jack and soldered the + battery lead to ground.  no change.

for kicks i flipped around my trimmer.  little change, but it might be my battery from messing around with this thing for hours.

now i noticed, that since i disconnected the jack, when i click the switch, the led will turn on without a cable in the jack.  does this mean that the switch is wired incorrectly?

[caress]

man IMHO i would just make a new one from scratch and then check over the other one afterwards...driving yourself nuts over a couple dollars worth of parts is sometimes not the best use of one's time.  sometimes it's the simplest thing wrong, but you just can't see what it is...very frustrating.  since it's such a simple circuit, it would be a piece of cake to just make a new one...maybe not the case if you were making an analog delay or something like that, though.  it's only a fuzz face!

[petemoore]

  I built a testjig, has 2 jacks, wire for grounding them is long with a testclip, each jack tip gets a wire and testclip.
 I put that in a raco box, then put a cardboard box mounted on top for the circuit in test to sit on, anything non-conductive.
 This way I can verify that input indeed comes from the guitar side cable tip, and the output actually gets to the output cable tip [where it'd go in the amp], with the DMM, lastly test both jacks and the wire/clip are connected [grounds].
 I like this way because I can lose the bypass switch, dc jack etc. and just test the circuit board and necessary offboard stuff [like volume/gain pot], I put holes in the sides of the cardboard for stuffing pots into. Test for no PS shorts and that the battery is good, eliminating as many variables as possible to concentrate on debugging the board.  
 I believe every resistor and connection can [and probably has been, at least once by now] be measured with the DMM.
just set it aside for a time or two.