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Projects => Tech Help - Projects Page => Topic started by: night-B on March 08, 2011, 05:12:46 PM

Title: Please help me...
Post by: night-B on March 08, 2011, 05:12:46 PM
Hi guys!
I've got a serious problem with my last 3 builds (one is already in the tech help : the kokbox).
Here's the problem : I built a firebomb, a kokbox and a retrograde. All the three were working in the test box, then I boxed and wired them. The kokbox didn't worked after boxing but the retrograde and the firebomb were fully working. I played with them, plugged and unplugged 3 or 4 times, and then they didn't work anymore  :'(
On these 3 the bypass and the led are normal, simply no sound at all when engaged. I only use brand new 9v batteries.
Since the problem appears to be on all my builds I'd like to know what's going wrong to take a lesson for the future. Is it a bad solder (I use 60/40 rosin solder)? grounding problem? Broken wire (I use stranded untinned wire)? Everything looks fine in the box.
Now that all my madbean's project aren't working anymore it drives me crazy and I absolutely don't know where to look at  ???
Damn they worked perfectly...
Title: Re: Please help me...
Post by: k.rock! on March 08, 2011, 05:21:47 PM
I'm having a similar issue with a non-Bean project that worked great and then of all of a sudden, no more pedal...doesn't work with battery or power supply...it's just dead... ???

I haven't done a whole lot of troubleshooting yet cause I just noticed it yesterday afternoon. The only think I checked was contacts shorting into something, bad connections, overall soldering, disconnected wires and finally swapped the IC on it...but it seems like will be one of those projects where the problem lies in a bad component :(

Hope you get yours fixed! If I get something to work in my project that I think might be a possible issue you may be having as well I'll post it here :)

Good luck man!

-Kaleb
Title: Re: Please help me...
Post by: jkokura on March 08, 2011, 05:49:32 PM
Hey guys.

Well, there's two potential problems here, and in both cases you're going to have to take it out of the enclosure.

First off, sometimes things rotate in our enclosures, especially if we didn't tighten them using a a socket. Things like Jacks, Pots, and switches can rotate and then ground out against something else. This is particularly common with jacks actually. The solution to this is to open the pedal up, and then insert a plug into each jack, looking to see if either the lugs or the actual contact mechanism is grounding out against something else.

Secondly, sometimes wire breaks, or parts fail, or you plug the wrong kind of power supply in and you fry something. It doesn't sound like you fried anything, and the enclosure protects it from interference, but it could be that something is failed. Sometimes under stress wires and parts just stop working right. The solution to this one is a lot more involved than the last problem, it means you need to take the pedal and use a multi meter and probe to find where your problem is.

My recommendation is to take it out of the box, and remove the jacks, switches, etc. Then check the board again (Rock it before you Box it). If the board is working fine, you know the problem is in your wiring and then it's just a process of elimination. If the board isn't working fine anymore, start with an audio probe and start looking for the problems. It could be a failed part, so having spare transistors and IC's around is a good thing to do. Resistors and Caps don't often fail (except Electrolytic, but that's because of age or too much power). Diodes can sometimes fail, but if they're just there for clipping that wouldn't be the problem.

I hope that helps both of you guys.

Jacob
Title: Re: Please help me...
Post by: night-B on March 08, 2011, 05:52:42 PM
Thanks guys!
It's very strange that 3 builds stop working like that...
For my components I order from Banzai Germany.
I use : panasonic Ecq or Wima mks caps (all 25 or 50v), metal film resistors 1/4w, switchcraft open jacks, "high quality" stranded 0,25mm² wire, cheap taiwanese 3pdt, miyama switch.
Pandadandan told me that the bs170 of the kokbow are static sensitive but they are not present in my retrograde.
Since I have 3 broken pedals there will be hours of debugging...
Title: Re: Please help me...
Post by: CRBMoA on March 08, 2011, 06:17:39 PM
I would have to say that nearly ALL of my debugging issues have been traced to poor solder work (repair builds ESPECIALLY, but often in my earlier work, too), broken, frayed wires (repair work, my own builds; solid core is NOT very forgiving, and even stranded wire has a limit to how much manipulation it will tolerate).

If you make sure your circuit works before you enclose it, unless you have a bad power supply, it is nearly always a physical/electircal connection issue.
Title: Re: Please help me...
Post by: night-B on March 08, 2011, 07:06:00 PM
There must be a "thank you" button in the forum  ::)
Title: Re: Please help me...
Post by: jkokura on March 08, 2011, 07:34:24 PM
'liked'

Jacob
Title: Re: Please help me...
Post by: bigmufffuzzwizz on March 08, 2011, 11:43:44 PM
Quote from: jkokura on March 08, 2011, 05:49:32 PM
First off, sometimes things rotate in our enclosures, especially if we didn't tighten them using a a socket. Things like Jacks, Pots, and switches can rotate and then ground out against something else. This is particularly common with jacks actually. The solution to this is to open the pedal up, and then insert a plug into each jack, looking to see if either the lugs or the actual contact mechanism is grounding out against something else.

This has happened to me quite a lot recently. Also components shorting out against the bottom of the enclosures that gets screwed on.
Title: Re: Please help me...
Post by: night-B on March 09, 2011, 11:52:11 AM
In one of those build, even if there were no jack inserted, when I started to unscrew the pots, the led was flashing like a christmas tree. Looks like I've got something shorting.
I'm checking with the DMM but the wires seems to be unbroken, the switch works fine.. No grounding of the Tip of the jacks...
Another question : do you guys cut the little tip of metal near the body of the pot, grounding it to the enclosure?? If I let them in place my pots aren't able to be screwed in line with the hole of the enclosure, they look like the Pise tower outside of the box  ???
Title: Re: Please help me...
Post by: gtr2 on March 09, 2011, 12:39:33 PM
Quote from: night-butterfly on March 09, 2011, 11:52:11 AM
In one of those build, even if there were no jack inserted, when I started to unscrew the pots, the led was flashing like a christmas tree. Looks like I've got something shorting.
I'm checking with the DMM but the wires seems to be unbroken, the switch works fine.. No grounding of the Tip of the jacks...
Another question : do you guys cut the little tip of metal near the body of the pot, grounding it to the enclosure?? If I let them in place my pots aren't able to be screwed in line with the hole of the enclosure, they look like the Pise tower outside of the box  ???

Cutting the "nub" of of the pots is pretty much standard practice.  The nub is to stop the pot from turning when you turn the pot.  For stompboxes it's not really needed.

It sounds like the pcb may be grounding to the enclosure.  This would create a closed circuit for the led to light up if you touch to ground in that area at the right spot.
Title: Re: Please help me...
Post by: night-B on March 09, 2011, 04:20:11 PM
On the retrograde, still good bypass and no signal when agaged even if the boards doesn't touch anything...
Wiring appears to be good.
The only thing I don't know is that the red spotted area have continuity with the ground when I check with my DMM. I can't see any solder bridge  ??? Is it normal?
When the pedal is plugged, I have continuity between the +9v of the board and the ground.

[attachment deleted by admin]
Title: Re: Please help me...
Post by: madbean on March 11, 2011, 05:38:21 PM
Hmm...that's messed up. You should have no continuity between ground and those two traces. Hit the gaps between with an Xacto knife and see if that fixes it. Are the tabs from the transformer touching anything?
Title: Re: Please help me...
Post by: night-B on March 11, 2011, 06:01:26 PM
I have ripped a bit the gaps with an Xacto. There's still a continuity with the ground. I checked with an audio probe and I lose signal here... I had an idea and BINGO!
In bypass ok, when engaged I inverted the input/output jacks and everything works fine!!!
I checked my wiring and inpout/ output of the board are wired at the good place on the switch.
Hum such a nooooooby problem here  ::)
I don't understand why it worked normally first... It sounds so great, but with jacks inverted lol  :o
Maybe I have the same problem with my other pedals, I'll check ASAP.
Title: Re: Please help me...
Post by: CRBMoA on March 11, 2011, 06:14:21 PM
So does that mean it works now? I can't quite follow your post. Maybe I need more coffee.
Title: Re: Please help me...
Post by: madbean on March 11, 2011, 06:15:41 PM
I think so. Easy fixes are the best!
Title: Re: Please help me...
Post by: night-B on March 11, 2011, 06:19:25 PM
Yes it do works. Sounds great I'll post it in the build reports. I don't know why it's inverted with the jacks.
Thank you so much for helping me even if I made a very very stupid mistake...
Title: Re: Please help me...
Post by: madbean on March 11, 2011, 06:59:52 PM
I've made the same mistake as recently as my Echobase build. Hooked it up on the test rig, fired it up...WTF! It took me 10 minutes to realize I had not connected the input wire to anything.
Title: Re: Please help me...
Post by: night-B on March 11, 2011, 07:14:10 PM
Hours of brainstorming because I have put the input jack on the wrong side of the enclosure. Sorry for this stupid thread!
Edit: The second "broken" stompbox had the same problem. The third the kokbox is still dead, I just received some replacement BS170 yesterday, I'll try to swap them.
Title: Re: Please help me...
Post by: k.rock! on March 12, 2011, 07:33:38 PM
I'm glad you were able to fix yours night-butterfly! For those who care, I posted something similar here in a reply mentioning I was having a similar issue with another build. In my case it was the diode used for power supply polarity protection. Don't know exactly how it got compromised (my cousin only uses this pedal exclusively on a 9v battery so the possibility of plugging in the wrong power supply is not in the picture). I guess I had a faulty diode to begin with and only lasted so long, so in the circuit it was acting as a short circuit which in result it ended shorting pin 8 on a JRC4558D (+V) to ground...hence the pedal apparent "death".

Anyways, thank you all for helping night-butterfly at the same time you were all helping me :)

Just a side-note...the DMM is definitely your friend! Specially the continuity functions!  ;D


Kaleb
Title: Re: Please help me...
Post by: night-B on March 12, 2011, 09:19:19 PM
Glad to hear you found the faulty component! I'm hunting in the same way on my kokbox, but I'm so happy my 2 other pedals are on my board again  ;D
Thanks guys !
Title: Re: Please help me...
Post by: bigmufffuzzwizz on March 13, 2011, 04:52:40 PM
.
Quote from: night-butterfly on March 11, 2011, 06:19:25 PM
I don't know why it's inverted with the jacks. Thank you so much for helping me even if I made a very very stupid mistake...

I'm glad to see you got your two builds working. These "stupid" mistakes are very necessary for us to learn and use as a reference. We all make them, now great troubleshooting!!!

Quote from: k.rock! on March 12, 2011, 07:33:38 PM
Just a side-note...the DMM is definitely your friend! Specially the continuity functions!  ;D

Yes!! I use it all the time. Sometimes I think I'm being too careful when I find myself testing continuity on every single solder point.