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Slambox power issue

Started by Background Noise, March 31, 2011, 01:52:30 AM

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Background Noise

I wired power to the slambox according to the instructions.....

http://www.madbeanpedals.com/forum/index.php?topic=155.0

When I tested it I had a bypass signal, but the pedal signal was silent.  I was hearing a click when I matched the "wrong" terminals on the battery.  So I switched the terminals around to that the red "positive" was attached to the ring on the input jack and the black "negative" was attached to the ring on the power jack.  

Oddly enough the pedal worked, as far as the battery was concerned.  When I took the battery out and connected it to the DC power it will still give a bypass signal but the pedal  signal was silent.  It seems as long as it gets power it is working properly.

The only other issue is that the pot increases gain counter-clockwise, but I assume I just need to switch lugs one and three on the pot around.

The only deviation from the wiring scheme above is I am using a pcb for the switch and have the sleeve connected to ground on the pcb.  Also the SW hole is left vacant because the pcb had no place for it.  Admittedly I don't understand exactly what the SW does, it that my problem?

PCB is listed here http://www.guitarpcb.com/apps/webstore/products/show/1343792

Thanks for any input.

gtr2

SW is for the led.  You don't need to use this if you have the led on your 3pdt pcb.

You are correct, switching your wires on lugs on 1 and 3 will fix your pot.

I don't understand your description of the wiring/power/bypass problem.  But you can check to make sure your getting voltage to the board with a multimeter by placing the red probe on 9v pad and black probe on the GND pad.

A picture would really help here because I don't quite understand what you did based on your description.  To me it sounds like you said you hooked up the dc jack positive to the input jack sleeve which would be wrong.  Pictures are worth a thousand words.  ;)

Josh
1776 EFFECTS STORE     
Contract PCB designer

Background Noise

Thank you for your help.

I changed the battery back to its correct orientation and I am now getting consistent power to the board from both the battery and DC jack.

Unfortunately it is now back to its original condition meaning that no sound comes out at any time.

I am need to try some things before I bother you guys with anymore questions.

I am sure I will confused again soon enough.

jkokura

Well, If we had some voltages on your transistor we'd have something that may help us help you.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Background Noise

#4
Quote from: jkokura on March 31, 2011, 04:33:31 AM
Well, If we had some voltages on your transistor we'd have something that may help us help you.

Jacob

I apologize, I am new to electronics in general.

I obtained a multimeter, what this showed me is that my DC input was actual working (measuring 9.3 at the board), my battery was not (measuring .86 at the board while the battery measured 8.2).  I switched the battery terminals back to the correct places.  Now I am measuring 9.3 with DC power and and 8.2 or so with the battery.

As I said I now get no sound at all out of the pedal.  I just got done creating an audio probe and will probe it tomorrow.  I now believe that the problem is on the pcb.  This is my first pedal so who knows what I have screwed up.  

My post was a little hasty and not well though through, but I only have a few hours a day to make noise and I get a little rushed.  Turns out my children do not appreciate a Super Reverb like I do.

I appreciate your help and patience.  Next time I will try to include far more relevant data.

jkokura

I think you are misunderstanding me. I got what you meant, that you now have power at the board, which is good.

But what I was asking for were the voltages at each pin of the transistor, which is on the pcb. I agree that the problem is there, and the transitor voltages will help immensely.

Perhaps you should go take a look at the "how to ask for tech help" thread?

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Background Noise

#6
Quote from: jkokura on March 31, 2011, 06:46:25 AM
I think you are misunderstanding me.

You are correct sir.  I believe I have now caught up.

I have readings on the BS170 transistor, I am a bit unsure how to report them but, the "D" pad is reading 1.43, the middle pad is reading .71 and the "S" pad in the corner of the pcb is reading 0.

Just to clarify, I took these measurements by placing the red probe on the respective pad and the black probe on the Slambox pcb ground.

I also took some photos..........






I intend on doing the audio probe procedure tomorrow, so feel free to wait for the info to post if it is necessary.  I am sure I am missing something, but hopefully this is a more complete collection of information.

I appreciate the help not just with obtaining a working pedal, but teaching me how to ask the right questions.  


gtr2

#7
I don't know what the transistor voltages "off hand" are on this but those are definitely not right.

FET transistors go by the terms drain, gate, source for their terminals.  Data sheets can help you with which leg is which.  Just type the part and google away.  I'll do the first one for you

http://www.fairchildsemi.com/ds/BS/BS170.pdf

Josh
1776 EFFECTS STORE     
Contract PCB designer

Background Noise

Quote from: gtr2 on April 01, 2011, 02:00:39 AM
I don't know what the transistor voltages "off hand" are on this but those are definitely not right.

FET transistors go by the terms drain, gate, source for their terminals.  Data sheets can help you with which leg is which.  Just type the part and google away.  I'll do the first one for you

http://www.fairchildsemi.com/ds/BS/BS170.pdf

Josh


Thanks much.

I may ask many questions, but I only ask them once.