Hi guys!
I've got a problem with my kokbox. I've populated the board and wired the 3PDT, then I tested it with my test box and everything went fine. Now that I boxed it i have a bypass signal, but no sound when the effect is engaged. The led is lighting correctly. The only issue I had is that I had to force a little to let the pots (9mm board mounted) pass into the drilled holes of the enclosure. So I soldered them again but the problem is still here. Do you think I must change the pots?
Tell me if you need gut pics or voltage readings.
Thanks for the help!
Could be a grounding problem. Does it still work outside the enclosure?
Jacob
Do you have a multimeter? Try testing the pot. You can either test it with continuity or resistance. Touch from lug 3 to lug 2 and turn the pot fully one way. See if it goes from full resistance to 0 (or vice versa). Then with lug 1 to lug 2. If you get resistance or continuity then the pot should still be good and working! I've have weird shorting issues before. Look at how the jacks are orieneted. If would short if the tips where touching the enclosure(ground). I've rubbed all the components on a fresh build not working to find out the transistor wasn't in the socket enough! You never know. Also did you check continuity on the footswitch??
Damn! This pedal worked with my test box :'(
Checked all the pots with the DMM and the resistance changes when I turn the pot.
Checked the 3DPT, it's switching correctly between the wires.
Even if the out jack is very close to the DC jack and the enclosure I don't see any grounding, and the bypass signal is OK.
Is it possible that I fried a BS170 with static electricity when I enclosed the circuit?
Edit : Even if the PCB is out of the box it still doesn't work
Possible but unlikely. Take it out of the box and test it again. If it doesnt work then, remove the switch and jacks and just see if the board with pots works. If it doesn't, then start checking the board for issues.
Jacob
I think I'll unsolder the jacks and switch, and go back to the test box :-\
Signal from jacks to the pcb is Ok. I haven't found grounding issue yet.
The voltage readings are fine on the transistors but now the led never lights off, even If I unplug the jacks.
Looks like I have wiring issues I can't find...
did you get signal again with the test box? that LED issue has happened to me with a few of my builds. the LED stays light with no cables plugged in. but it doesn't happen with a battery so i don't worry about it!
With the test box I get ground noise and no guitar signal... I have the Led problem with a battery! Maybe my DC Jack wiring is wrong... It has already confused me on an older build. I hope this is the problem.
I wired the left lug to +9v battery, center lug to +9v board, right lug to the ground on the switch.
Is it right? I followed this diagram http://www.madbeanpedals.com/forum/index.php?action=dlattach;topic=707.0;attach=212;image
[attachment deleted by admin]
That's right.
Were you careful with your BS170s? They're extremely static-sensitive.
I might have damaged one when I boxed the PCB. the voltage readings are fine but I'll order some replacement transistors.
I'v fully rewired the pedal, this time I used the Pandadandan wiring method. I still have the same problem.
I'll take another set of transistors on my next smallbear order, then if it's still problematic I'll go on caps replacements...
Quote from: pandadandan on February 26, 2011, 11:48:04 AM
That's right.
Were you careful with your BS170s? They're extremely static-sensitive.
what would be the proper way to handle theses if we don't have a static ground wristband?
Carefully with 2 sets of pliers??
Quote from: bigmufffuzzwizz on February 27, 2011, 03:16:33 PM
Quote from: pandadandan on February 26, 2011, 11:48:04 AM
That's right.
Were you careful with your BS170s? They're extremely static-sensitive.
what would be the proper way to handle theses if we don't have a static ground wristband?
Carefully with 2 sets of pliers??
Yeah I often just try and earth myself somehow before I handle them (just touching my amp faceplate is enough to discharge the static I'm carrying). After that, I try and avoid generating any more static. I don't use a wristband either, by the way.
Wearing latex gloves can do the trick right?
Quote from: night-butterfly on February 28, 2011, 05:33:39 AM
Wearing latex gloves can do the trick right?
This really shouldn't be necessary. I think an audio probe will help you track down the problem. Check at the drains of each transistor to see where the signal is getting killed. This is the fastest way to debug this kind of problem.
On the bs170s the voltage readings are approx 1,5v 2v and 7v for each transistor. Ill check if I have a spare 0,1uf to build an audio probe.
Thanks for the help guys!
I have the same problem! Night-B, did you solved this issue? :-\
At first my kokbox worked out of the box, I forced a little on the knobs to pass threw the holes of the enclosure, and then it stopped working. So I thaught I broke a mini pot but I checked them with my dmm and they worked correctly. I checked the voltage readings of the transistors... This has drived me silly so I changed all the pots, trannies, then I have completely rewired the 3pdt and the jacks, and it finally worked. I had no audio probe at that moment so I don't know where the problem lied. Btw it was one of my first builds and I made lots of noob mistakes.
I hope you'll find how to get yours working!
Edit: I wore gloves to place the trannies on the second time...
After a few months, I took my Kokbox from a shelf and played with it. Now it's "working", but the sound is very gated and it's very frizzly and fuzzy... :-\
Any suggestions are welcome! Thanks! :)