I've been testing this thing for 2+ hours now and can't figure out what I'm doing wrong. Here's the details:
Bypass works, but no signal or LED when engaged - just a clicking noise that responds faintly to the volume knob.
Is this a grounding issue? I've checked the border of the grounded area and cannot locate any traces that have leaked onto it.
Any help is greatly appreciated!
(http://www.csmworship.com/Gear/Scrat/DSC04798.JPG)
(http://www.csmworship.com/Gear/Scrat/DSC04800.JPG)
I don't see power going to the LED--I see one leg of the LED going to the top left lug of the stomp and another leg going to a resistor and then sleeve of the output jack.
Disconnect the led from the output sleeve. Run a wire from the power jack (not the battery tab!--the other power tab) to a resistor to the long leg of the LED. The short leg then goes to the top left of the stomp. That's the method I use to 'off-board-wire' an LED.
That's the only thing that jumps out as long as you're certain the stomp switch wiring isn't shorting against any neighboring wires.
The Grapevine has spots for the LED on the board - I can see a floating resistor attached to your LED, but you've also obviously got the LED resistor in it's spot on the board. You've almost certainly got something wrong there because of that. The Project page for the Grapevine should help you find out where the LED connects to the board.
Jacob
maysink - Thanks for the tip. Will try that when I get home in a bit and see if that fixes the LED problem. I was going by a different layout for the off-board LED, so I appreciate the clarification!!!
jkokura - It does? Looking at the project PDF now, but don't see anything like that. I'm using Ver. 2 if that makes any difference?
It's also worth noting that the no-sound-only-clipping-when-engaged problem existed before I even added the LED, so I'm guessing it is unrelated?
Thanks for the replies so far!
You might take a pic of the component side of the board, too.
It looks like one leg of C3 (the one NOT going to ground) could use a better solder connection.
All right...
I updated the LED wiring as per maysink's suggestion, but still no light or sound (except for the clicking). I will upload pics of that as well as the component side later tonight.
Yeah Maysink is right about the LED. It's not in the board like jkokura said. Is the clicking sound constant or are you talking about the click when you step on the switch. I have a feeling you might have a problem with your dc jack wiring.
The tip/ring/sleeve can be confusing but basically, if you look from the back of the jack, you should have 3 contacts wired like this:
___ = ground on switch
0 = 9v to your board and to the resistor end of your LED
0 = +(red) wire of the battery tab
If my confusing drawing doesn't help, take a look at madbean's new dc layout
http://www.madbeanpedals.com/projects/Cherrybomb/docs/Cherrybomb_ver1.pdf (http://www.madbeanpedals.com/projects/Cherrybomb/docs/Cherrybomb_ver1.pdf)
You're right! So many of them do, I just assumed that it did. When I built mine I don't remember, but then again I usually don't add the Resistor to the board and do it a different way...
Are you getting this ticking while using a battery at all? Sometimes it helps to use a battery rather than a power supply to trouble shoot. Also, if the battery gets hot and the problem still exists it's easy to tell that your power is going to ground. This may not show up as easily when you use a power supply.
Another thing you might try doing is simply hooking up power, ground, and input and output jacks to the board and seeing if the board works. After all the looking at the wiring and power it might just be that you have a cold solder joint or backwards part or something.
Jacob
SHAMELESSLY lifted from the BYOC Forum's legendary "Stephen's tips for a successful build" (http://www.buildyourownclone.com/board/viewtopic.php?f=9&t=6401) which really is required reading.
If you're wiring up an off-board LED, run a second wire from the lug labeled "To POS on PCB" > current limiting resistor > long LED leg and then short LED leg > top left stomp switch lug.
(http://pic20.picturetrail.com/VOL83/511092/16553671/347537547.jpg)
Ok... double-checked the DC Jack wiring and it is correct. It may not have been in the above pictures, but it is now. LED wiring should be correct now too, also different from earlier picture.
Jkokura - just tested with battery, and it got hot pretty quickly, so this definitely looks like a grounding issue.
What's the best way to test for where the short might be? Thanks again guys...
Well, there's lots of ways it could be grounding the power - one would be by bad wiring, another would be backwards part on the board, solder bridges, and that's not even considering how you're mounting the board in the enclosure, and how the jacks are connected.
What I would do if I were in your shoes (I have been...), is I would start over from scratch on the wiring. I would unsolder all the wires from the board, rexamine every solder joint and part to make sure they're in correct and with the right orientation, and then I would very slowly redo all the wiring again. It sucks, I KNOW, but it will hopefully help you...
Jacob
Yep. You're in for some learning! Seriously, I've learned more about this stuff from the ones that don't work than those that do.
Once you desolder all the wires from the stomp switch, you can confirm the stomp is still functional by using a digital multimeter (set to the diode/continuity mode) and test the middle row of lugs to the bottom (or top)--the middle-left should 'beep' w/ the bottom-left; center to center & so forth. Click the switch and the middle row will 'beep' with the top. That make sense? The middle row of the stomp switch is always 'on' and connected to either the top or bottom row depending on when last you stomped.
Be sure to check the link I posted above and read up on tinning wires and making mechanical connections before soldering.
Despite what my situation suggests (and the messiness inside the box), this is actually my 4th pedal build ::)
I've had to hunt down a cold solder joint here and there, but I just can't seem to figure out where the glitch is in this one. I'll start the rewiring process... if anyone thinks of anything else I should test out in the meantime, let me know!
Try an audio probe to see if you are losing signal at the first gain stage. You want to hook the lead of your probe up to the drain of Q1 (the trace under R4) to see if you have signal there.
Also, let me gently remind everyone to never, ever, ever put your build in an enclosure before testing it out on a breadboard (or prototyping board). You are setting yourself up for a lot of grief if you don't.
PS I'm not picking on you, eldanko. I just would like everyone to start doing this...it saves so much time.
Quote from: madbean on July 20, 2010, 03:35:01 AM
Also, let me gently remind everyone to never, ever, ever put your build in an enclosure before testing it out on a breadboard (or prototyping board). You are setting yourself up for a lot of grief if you don't.
i'll second that! i remember my first build drove me nuts trying to figure out why it wouldn't work and I wish I would have prototyping board when i built it (and that was just a simple Sabertooth build).
it's really easy to build something like a Beavis Board, in fact, if you go to his website he tells you how to build his I/O breakout box, the rest is just breadboards, a terminal strip, and a battery snap. so easy to build, and worth every bit of it. makes breadboarding go so much faster and helps prevent headaches later on! here's the link to his instrustions: http://beavisaudio.com/bboard/images/io_diy.jpg (http://beavisaudio.com/bboard/images/io_diy.jpg)
I think I will create a tutorial on how to build a simple testing rig, too. You can do one for probably $20.
You were reading my mind! :o
You guys rock. Yes, definitely going to breadboard a bit in the future. Yes, never going to install the board in the enclosure before thorough testing. Learning a lot so far.
Onto the techy stuff...
Doing the audio probe thang. I do NOT have signal after the first gain stage. The second leg of Q1 has signal, albeit a tad quieter, but the third does not. What does this mean?
This is what you are looking for.
[attachment deleted by admin]
Thanks for the illustration! Talk about customer service... :)
Ok - I double-checked the solder joints of Q1, and now I'm getting a signal on the 3rd leg, but it's incredibly weak. Is something wrong with the transistor?
If you have extras, I would replace Q1-Q3 and see what happens.
Where did you get your transistors from?
are people posting pictures in this thread? because I can't see any of them.... weird.
Hey guys -
Sorry it's taken me so long to get back - out of the country last week. Ok...
Bought my transistors from Pedal Parts Plus. I've replace Q1 and still am not getting a signal on the 3rd leg of the transistor (speaking in order of signal flow). Should I continue replacing Q2 and Q3 or address this problem first?
Are you sure of your pinouts on your transistors? Double check that your orientation is correct not just to the image for the layout, but to the pinout on the layout.
I have used transistors with a backwards pinout to the normal pinout - sometimes companies use opposite pinouts for trannies compared to the same models from other companies.
Jacob
Ok. Resurrecting this thread because I'm STILL baffled.
I've socketed the transistors for easy switches. I've tried both orientations and still haven't gotten any signal past Q1, even after replacing Q1-Q3. I've tried two different batches of transistors.
Thoughts, friends? ???