Box of Rock - no sound - HELP!!!

[stleon2]

Can't figure it out. Just all of the sudden the Distortron side stopped working. Bypass, fine. Boost, fine. Engage the drive side, no dice. It is dead silent unless you turn all the knobs all the way up. Then it sounds like a faint guitar through a tin can. I took it apart and was hoping to find a cold solder or loose wire. Nothing out of the ordinary.

I have a multimeter and very limited electronic knowledge, I tried to trace the board to find the break in the circuit, but I am a little overwhelmed.

So, is there any components that are more prone to failing than others, can someone give me a starting point on where to look?

Thanks.

 

[Brocko]

Can you see any components that look burnt out? There is a small resistor near the 9v input with a diode near it you might want to check. I repaired a pedal just by changing these once.

If you can post pics of the circuit there are some clever guys on this forum who can help you

 

[Canman]

I've heard of issues similar to this being fixed by tightening the input/output jacks...maybe those came loose?

 

[stleon2]

Okay. Here you all go. Please help! Hopefully someone can see an obvious fix here.

 

[dickjonesify]

I don't see anything obvious but I do wonder why this slot is empty(?)
Every other pad has a cap or diode or resistor in it.
I wonder if that's normal...

 

[dickjonesify]

If nothing looks burnt and it works in bypass....still hard to say.
I wonder if it could be as simple as a short at the switch. Maybe take really close up pics of the switch on the distortion side. Make sure no wires are touching eachother.

 

[Sp8ctre]

I'm an electronics technician and what I see here are some terrible looking soldering on all the Pots. I'd start off by re-soldering all those.

 

[dickjonesify]

^I agree with that.

The soldering on the board is great. The pots are awful.

 

[bugg]

I think what you guys are seeing is really shiny solder on the pots, not spots where the solder is missing. I could very well be wrong though, but most of the ZVex stuff I've opened up has been built pretty dang good.

I'd like to see a pic of the lugs on the 3PDT switches if possible.

So, is there any components that are more prone to failing than others, can someone give me a starting point on where to look?

Switches, jacks, plugs, and wire junctions.... Those are the common spots of failure on stompboxes.
Sure, it could be one (or more) of the mosfets, but it's almost always some form of physical damage.

Like I've offered to a few other members here.... if all else fails, send it to me and I'll try to fix it for ya.

 

[Shortscale]

Might sound like a dumb question but have you isolated the box so nothing else is plugged in to it except the guitar and amp and also tried different cables?

 

[Brocko]

Those two empty areas are not necessarily anything to worry about. Remember there are other pedals based on the BOR (Distortron, Double Rock) so they might be board ready spaces for components of those pedals - i have seen others do that. So its possibly just for that reason. I had a behringer phaser with a 'missing component' - i tested putting on in with the value it gave and it made the phase a lot slower ( i ended up doing it as a switchable mod).

(a mate had a keyboard - he opened it up and found it was essesntially the same chip as an upgraded one with more sounds - they just simply disabled the sounds on the cheaper one).

 

[bugg]

Those two empty areas are not necessarily anything to worry about.

This is very common, look how many components are missing from my Super Badass Distortion PCB.

 

[stleon2]

Might sound like a dumb question but have you isolated the box so nothing else is plugged in to it except the guitar and amp and also tried different cables?

Yeah, I exhausted all other reasonable failures before opening up the enclosure. Whether in the effects chain, or isolated, using different cables, powering via PP2+, one spot or 9v battery, it always worked bypassed and with the boost, but the Distortron side just goes silent, no buzz, no nothing. That is, unless I crank all the knobs full on. Then I hear some guitar but it's faint and tinny/fuzzy.

I will try to get some shots of the switch today and post. Thanks so much for the help so far guys!

 

[snaredrum]

And the input/output jacks are screwed onto the enclosure properly, are they? I know Tweaker mentioned it above, but that is what fails first in lots of pedals. If there's some sound when the knobs are cranked, that suggests what, a lose connection?

(I'm not so hot on the building thing...)

 

[stleon2]

Yeah. Tightened them down too. Nothing helps.

 

[SonicBoom]

OP - I had two similar issues with a BOR clone that I built - one was a pot barely shorting against the box and the other a bad switch. If the boost works, ignore power and input jack issues b/c signal has to pass through those to get to the boost section. Assuming all solder joints on the pots and switches are good (check by giving each a light tug), check the Distortron-side switch by flicking it hard with your finger while the Distortron is engaged (no sound). If that has no effect, it may be a transistor in the Distortron section.

I believe these units had an issue early on in that they would occasionally blow a transistor. A protection diode was added in later units to prevent this.

Given your limited electronics knowledge and tools, you may have to send it to Zvex or a good tech.

 

[stleon2]

Sorry, couldn't get any closer with the iPhone camera. If these aren't good enough, I could try again with the DSLR and try to work on getting macro shots. I'm still learning...

 

[SonicBoom]

The solder job is not the best but the wires appear to be connected. Have you given each wire to the switches a light tug to make sure the connection is solid - especially the yellow wire? Sometimes the strands of wire can break, causing a poor connection.

Did you test the Distortron switch by tapping on it while playing through it? Also, when did this fail - in the middle of you playing through it (after you switched it on and were playing through it) or when you went to switch it on it just didn't work? Switches usually fail during the act of switching, not while just sitting there.

 

[bugg]

Nothing horribly obvious in those pics... SonicBoom's advice is good, aside from that it's tough to say without seeing it in person.

 

[GreenFlame]

Hey, i have the same problem with my Box of Rock. Have you solved the issue?