help a noob out? (slambox)

[jkokura]

You're getting -9v because you should put the black probe to ground. Switch them and you should get +9v again.

What are you readings with black probe on ground and...

Red probe at 9v in on pcb

Red probe on ground on pcb

Red probe on each pin of transistor.

Jacob

[jiffy]

Okay, the fact you get -9V seems okay since you had the black probe on +9V. (it's the norm to always put the black probe on ground though)

Okay with the pot, pad 1 should always be ground, pad 2 can be ground depending on the orientation of the pot. If you move the pot to 12 o'clock you should get a voltage on it. (for all these measurements make sure the black probe is to ground.)

[jtn191]

Jacob:

1) 9V
2) 0V
3) S= 9V   middle= 2.6V D= 0V

Jiffy:
with the pot at 12 o'clock, I'm getting 2-3V on the middle pad and 0V on either side

[jkokura]

Your power looks fine from the jack, don't stress about that.

However, the tranny looks not right to me. I'm not sure it's supposed to have 0 at the D pin. There's something not connecting in there, and I can't see it here.

Best thing to do would be to socket your transistor and then try a new one. I would check all the solder joints that surround the transistor and maybe try reflowing the joints.

Do you know how to use an audio probe?

Jacob

[jtn191]

No, I've not used an audio probe before. I googled them though and it looks like a pretty useful tool.

I'm thinking now I might have LED backwards because I misunderstood what "square side" meant. I thought it was square side of the white sketch, whereas it's really the square pad...  

[jkokura]

Does the pedal work? The led shouldn't affect the pedals working. It just doesn't light if it's backwards...

Jacob