Hey debug Big Muff!

[diemilchmann]

I have made a couple of these before, and i just decided to design a pcb for it. Unfortunately, its not working, and i have no clue whats wrong. The bypass works fine, but there isnt any sound once its turned on. Schem:
http://imgur.com/Vcuvw.jpg

Voltages:

Batt:9.39 v

Q1:

C .98
B .98
E .29v

Q2:

C .98
B .97
E .29

Q3:

C .28
B .95
E .96

i have a feeling the signal's getting funneled out somewhere.

thanks
julian

[Bad Chizzle]

Hello,

You're probably right, use a signal tracer at each section, starting at input. That works for me.

[petemoore]

  I'd measure-traces from the V+ to the collectors.
  Test for connections/ measure resistances...
   Since your battery is 'up' there's no shorting, always check for shorts before powering up.

[pleiades]

Look at Q3: with the collector biased well below the base, current won't flow from C to B and Q3 won't do anything.  From your schematic, it should be biased the same as Q1 and Q2, so if it's only at 0.28V, that could be your wiring issue right there.

[petemoore]

  Something similar is wrong with the four transistors..
  Base above emitter by 1 transistor diode drop [ie nearish gnd. 1.15v ?..would work
  The collector needs to swing voltage on both sides of the bias so 'centered'...something around 1/2v.
  It could also be pinout of transistors.
 

[diemilchmann]

I got sound!  there was a wrong resistor combination in there, and I replaced q 3, that seemed to work. thanks guys!