No sound in bypass or active mode on Russian Big Muff

[amonte]

I'm not sure what went wrong here...I've got a Russian Big Muff that had been working fine.  I had swapped out several components, including a resistor in the tone stack that I replaced with a trimpot.  The other day I was tweaking the trimpot and I accidentally closed the sharp edge of the lid down on the 9V battery connector.  The negative lead of the battery was dislodged from the snap portion.  Swapping the battery leads for a brand new 9V snap seemed like an easy enough fix - but after swapping the battery lead, the pedal suddenly does not work at all - I have static when the pedal is on but no guitar signal and when the pedal is off I have no signal.  The strange thing - and I need to reconfirm this because I might not be remembering it correctly - is that the volume pot on my guitar (which has developed a crackle) could be heard crackling through the unit when I turn the volume knob up and down.  Trying with another guitar did not help, same issue with no sound when active or in bypass. 

Using my meter, I checked for continuity between the battery leads and the positive points on the back of the PCB - they work fine.  I checked for continuity between the switch and the PCB - again, no problem.  I plugged in a cable to each jack and checked for continuity between the jacks - again, no issue.  I'm at a loss to what might cause in issue both in active and in bypass. 

Also - and I don't know if this is a clue or not - but that guitar crackle literally just started - right around the time I was originally tweaking the trimpot.  Probably unrelated but it seemed like a really big coincidence.

[amonte]

I think I stumbled across the problem (though not the solution).

I discovered that the full 9.5V is going across the input jack.  I also noticed that with a battery plugged in, the pedal is "engaged" as of there was a jack plugged into the input.

Could the issue be that the issue is the cheap input jack is shorting the connections together? 

[R.G.]

Read and follow "what to do when it doesn't work".

[amonte]

Read and follow "what to do when it doesn't work".

I'll take a look again, thanks.  I've read these before though and haven't seen this particular scneario in the past. 

[amonte]

This seems like an impossible long shot.  But what the hell...

I found this image on the Kitrae BMP site.  This board matches the identifier on my board



Those + and - battery pads look...strange.  Like the leads just pass through them but aren't actually connected to those points.

Looking closely at the top side of the board, it appears again that the leads are "passing through" these holes but not actually connecting.



Looking at the V7 board , you can see these terminals are left early and the leads are threaded through the two holes on the left.



So I'm going to give this a go.  I'll report back.

If this is obvious to everyone else, excuse my ignorance.  Just figured I'd share it in case someone else runs into this problem.

[R.G.]

I'll take a look again, thanks.  I've read these before though and haven't seen this particular scneario in the past. 

Actually read: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0 and follow the procedure.

It's a whole lot simpler way to get the thing fixed than wondering what people have seen before, or speculating about what you may see and may miss.

[amonte]

As luck would have it, I was right this time.  Removed the battery leads and soldered directly to +/- and it's all good now.

[amonte]

btw, if this came off in any way like I wasn't appreciating your advice, it wasn't meant to.  I just knew it had to be something with the leads as that was the only thing I had changed.

[EATyourGuitar]

to answer your second question that has nothing to do with the first question, that is called a strain relief. it makes the wire less prone to breaking away from the board when something is pulling on it. there is no difference in the schematic or the electrical function of the circuit to soldering something with or without it.

[amonte]

Thanks, I get that they're going through the holes for strain relief.  What I didn't get is why the strain relief holes had solder pads on them.  Especially when two other strain relief holes without pads were on the board and completely unused.  

[R.G.]

All's well that ends well.