FuzzFace makes no fuzz... (Dragonfly's PNP layout)

[andrew_k]

Hi guys, I wanted to hear he ye olde fuzz sound, so I built this on perf but I'm having a weird problem (and weirder voltage readings). Full debugging report as follows:

Circuit: Dallas Arbiter Fuzz Face (Ge)
Problem: There's no fuzz -- "fuzz" and volume pots affect volume, but there's no fuzz at all. Other than that, the circuit has no hum or other noise.
Source of circuit: http://www.aronnelson.com/gallery/v/DRAGONFLY-LAYOUTS_0/album18/album151/DALLAS_ARBITER_FUZZ_FACE_GERMANIUM_PERF.gif.html
Mods: Pulldown resistor omitted (plan on adding off-board)
Parts subs: none. using AC128 transistors; also tested with 2N3906 -- same result. Layout unaltered from Dragonfly's and remains positive ground.

Battery test - 9.29V

PLEASE NOTE: The following readings were taken with the red pointer thingy () on circuit ground, and the black was used to get the measurements. I figured that if it's positive ground this woud be the correct way to take the readings. If not, add a - in front of all voltages.

Q1
C: 0
B: 0.08
E: 0.13

Q2
C: 0.08
B: 0.13
E: 7.88

C1
+ : 0.06
- : 0.07

C3
+ : 0
- : 0.07

The zeros are an obvious stand out... I dunno, I'm just a n00b

Here's a pic of the underside of the board:



Any tips are greatly appreciated!

[frankclarke]

You are confusing collector and emitter, perhaps you should check the transistor pinout.

[Pedal love]

I would do a continuity check at all node points to each components lead. Check the batteries. Make sure everything is connected properly, including capacitors and transistors. Are there any component side images? Believe me, I have seen my resistors not connected where it would seem obvious.

[frankclarke]

Rear board looks OK.

[hellwood]

is there any reason that you are not using the excess wire from the leads of your components rather than extra wire? that looks like a disaster waiting to or already happening.

[petemoore]

C: 0
B: 0.08
E: 0.13

Q2
C: 0.08
B: 0.13
E: 7.88
  Q1 collector should be connected to Q2 base.
  Q1 Emitter should be connected to Gnd.
  *As long as your red/+ battery clip wire is connected to Gnd.,the supply is correct polarity for a +Gnd. FF, measuring the voltage differences between Gnd. and the relevant pins:
  Gnd. and emitter,
  Gnd. and base,
  Gnd. and Collector,
for each active. One DMM lead clipped to Gnd., the other probing pins, the *polarity of the leads and indicator in the screen are irrelevant, I suspect something may be confusing the readings information because the voltage distribution is 'backwards', the collector should have the highest potential from Gnd. the emitter should measure smallest voltage, being '1k from Gnd.'.
  Try clipping a lead to ground in 'beep' mode, then testing for ground on all grounds: volume and gain pots, Q1E, enclosure?, Jacks...anything marked Gnd., and the large battery clip button.
 

[andrew_k]

Thank you all for your responses 

frankclarke: I had the transistors in backwards! Thankyou, although the problem remains: Multiple volume controls, but no fuzz

Voltage readings with correct orientation:

Q1
C: 0.14
B: 0.8
E: 0

Q2
C: 8.19
B: 0.14
E: 0.8

hellwood: This was my second soldering effort and has sat on my bench for a couple of months waiting for me to buy some PNP germaniums. My more recent efforts have made use of excess component leads, been much neater and have all worked straight away. I figured my faulty implementation of such a simple circuit would be good for me as an introduction to debugging. After looking at the soldering, I'll probably rebuild it again anyway, but I'd like to try and work out what I did wrong

Pedal Love: Continuity check? I'm not sure what you mean -- I've put my DMM on 20Mohm setting with one end on ground and touched the other end one each component lead, all of which return some measurement. Is that what you meant? Battery is 9.2V measured at the3 battery and where the battery snap is soldered to the board. If I don't get a better result after re-soldering some joints I'll take side images as suggested.

petemoore: I did indeed have transistors in back-to-front... I feel like quite an idiot, but the learning process is like that sometimes. I don't know what "beep mode" is or if my DMM has it; what would the icon look like? I tested resistance between all ground points (sockets, pots, battery snap and circuit -- no enclosure yet) and all indicated they are connected.

Thanks again to everyone for your help so far, I'm going to have another stab at it with the soldering iron when I get home from work tomorrow and if I don't make any progress I'll probably scrap this one and build it again.

[Dragonfly]

check the resistors around Q2's collector...test values, check connections, voltages, etc.

[petemoore]

  Beep' mode is diode test mode, and looks like ---->l---, touch the leads together and it beeps, fun item for testing continuity of...solder joints or anything else. Of course if it doesn't beep...that would indicate non-continuity  of whatever your'e testing , handy for finding a 'stray' connection to eliminate..

[Pedal love]

For an explanation of continuity refer to Pete's post above.