Greetings forumites,
I've Just finished a Cherry Bomb and I have no sound.
I checked the signal routing and everything is ship shape.
I'm also able to hear the pots sweep, but no audio.
The voltages are a bit skew on q2
Source voltage is 9V
All readings taken from collector pin
Q1 0.6V
Q2 0.005V
Q3 5.2V
I also noticed that the 470R resistor from Q2 emitter to ground doesn't read any resistance in the circuit. I removed the resistor and it reads 470ohm.
I checked the transistor and it's oriented properly and specs out fine
I'm using BC184C's
I haven't tested the caps. Is it possible an electrolytic is oriented the wrong way? They seem to be oriented properly.
Any guidance would be great. This is my 20th pedal and I haven't experienced a strange problem like this before.
Just to be sure: you have the transistor turned 180 deg. from the drawing on the silk screen? It appears to have the opposite pinout.
The BC184C are oriented 180 degrees to the silk screen on the board. I also subbed in a 2N5088 oriented to the silk screen and it also read almost no voltage on the collector.
What about on the other side of R6, the 1k8. Are you reading about 9v there? R6 may be the problem.
R6 reads 9.3v
(I'm using a voodoo labs ISO-5)
Here are all voltage readings
Q1
C: 0.67v
B: 0V
E: 0.14v
Q2
C: 0.07v
B: 0.67
E: 0V
Q3
C: 5.18v
B: 1.59V
E: 0.97V
I also checked all electrolytics and they are oriented properly.
I'm stumped
R6 reads 2k. I'm thinking it got damaged by heat as it is 10% out of spec. I only have 2.2k resistors, but they should be fine considering the high gains of the BC184c
Edit: never mind. I removed R6 and it tests as 1.8k.
This is strange. no power in the circuit and I get screwy readings on Q2 collector and emitter resistors regardless of transitor type.
Wacky.
Edit: I just reversed the BC184C in Q2 to the silk screen orientation and it biases up properly, but it's oriented wrong for this circuit.
Still no sound.
I should have socketed this transistor the traces are starting to lift.
I may just move on from this one. If I keep working this board I risk damaging more components.