Glue guns and BSIAB

Indoor Fireworks · February 10, 2007, 06:24:01 PM

I just finished my BSIAB and I've got a mean buzzing sound. Everything functions properly, all the pots work correctly and so does the switch. The only problem is that it buzzes really loudly when the effect is turned on. I'm trying to figure out what I did wrong but I can't really find anything.

I was wondering if the problem might be my choice of glue. When I drilled the holes in the PCB for the stand-offs, I made the holes a little too wide. The standoffs fit, but they were a little loose so I glue gunned them to make sure the board wouldn't fall. Is it possible that the glue might be causing the pedal to buzz if it made contact with any of the connections or components?

I know I'm supposed to submit more info about the pedal but I don't have a meter to test this stuff. I hope this is just a simple problem but, if it isn't, I'll go buy a meter to test it and hopefully I'll be able to figure out whats wrong.

Victor · February 10, 2007, 06:31:45 PM

Maybe a bad solder joint? Any "crackles" associated in the sound?

I don't believe that the glue (isolant) can cause this.....

jonathan perez · February 10, 2007, 06:32:46 PM

glue wont conduct.

Indoor Fireworks · February 10, 2007, 06:40:22 PM

Hmm, no crackle. I wasn't sure if glue conducted. I guess I'll have to tear off the standoffs so I can get the board out and see what I did wrong.

JonFrum · February 10, 2007, 10:22:21 PM

It could be a bad ground somewhere.

Indoor Fireworks · February 12, 2007, 07:06:44 PM

Come to think of it, it does sound like a bad ground. Any recommendations on how to check if that is the problem?

boyersdad · February 12, 2007, 07:29:44 PM

With no meter, you may try connecting a cliplead to battery - and with the other end short out all the ground traces and tips of components on the board, and if the hum goes away, you have found a bad ground.

Someone else will probably have a better idea, but that should work.

Indoor Fireworks · February 16, 2007, 02:19:35 PM

boyersdad, did you get my message?

Indoor Fireworks · February 16, 2007, 02:53:49 PM

Quote from: boyersdad on February 12, 2007, 07:29:44 PM
With no meter, you may try connecting a cliplead to battery - and with the other end short out all the ground traces and tips of components on the board, and if the hum goes away, you have found a bad ground.

Someone else will probably have a better idea, but that should work.

Can anyone explain how exactly I can do this? Sorry, I'm a novice with electronics.

96ecss · February 16, 2007, 03:09:53 PM

Quote from: Indoor Fireworks on February 16, 2007, 02:53:49 PM
Quote from: boyersdad on February 12, 2007, 07:29:44 PM
With no meter, you may try connecting a cliplead to battery - and with the other end short out all the ground traces and tips of components on the board, and if the hum goes away, you have found a bad ground.

Someone else will probably have a better idea, but that should work.

Can anyone explain how exactly I can do this? Sorry, I'm a novice with electronics.

Hi,

Take a piece of wire, strip it bare on both ends. Make sure it is long enough to reach from your battery to all ground points in your pedal. Touch one end to the negative battery tip and one at a time touch it to all of your ground points on your pedal. Touch it to your jacks, and the ground strip on the pcb and all other ground points. What you're doing is re-grounding all of your ground points. If you touch a point and the hum goes away, you found your bad ground. I hope this helps.

Dave

Indoor Fireworks · February 16, 2007, 03:18:34 PM

oooooh, I get it. Alright, I'll give it a shot and see how it goes. Thanks!

Indoor Fireworks · February 16, 2007, 04:00:37 PM

Hmm, still no luck.

wampcat1 · February 16, 2007, 04:30:30 PM

I'm thinking the audio probe will be your best friend in this instance.

96ecss · February 16, 2007, 10:00:24 PM

I agree with Brian, it's time for the audio probe.

Indoor Fireworks · February 16, 2007, 11:55:10 PM

Alright, so let me get this right...

I take a 1/4 inch cable, cut off one end, connect an alligator clip to the negative lead and clip it to ground on the pedal, and connect a .1 uf cap to the positive lead on the cable. After I plug my power supply into my pedal, what do I do? Do I just touch each point that I soldered with the other end of the capacitor? I'm confused.

joegagan · February 17, 2007, 12:07:21 AM

I thought he was saying the pedal itself was physically buzzing.
That would have been a first.

anyway, check for bad soldering possibly at a ground. the old standby, move everything and gently twist the board etc while listening closely.
poke around with a small non-conductive poker while listening

John Lyons · February 17, 2007, 12:30:56 AM

You want to probe the points where sound should go in and come out. The gates and drains of the FETs, coupling caps...
The main places where you will not hear sound are the points to ground.
Start at the input and go along left to right as on the schematic.
It's going to be a bit hard to know where to check since it seems like you are usure of where things are and what they should be doing.
You will learn a lot if you keep plugging away.

John

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Glue guns and BSIAB