Cherry Bomb Q2 issue

[brooklynhero]

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.

[madbean]

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.

[brooklynhero]

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.

[madbean]

What about on the other side of R6, the 1k8. Are you reading about 9v there? R6 may be the problem.

[brooklynhero]

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

[brooklynhero]

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.