no sound when on, Bypass ok

[johnny5]

I just finished a Red Fuzz from a board i bought from GGG. i followed the layout on the GGG site http://www.generalguitargadgets.com/diagrams/red_fuzz_lo.gif as closely as possible.

project link
http://www.generalguitargadgets.com/index.php?option=content&task=view&id=65&Itemid=97

the bypass mode is fine but there's no sound when i switch it on. well, you CAN hear the distortion effect but VERY VERY low in volume. I kinda think that i am dumping all my signal to ground somewhere...... but cant find it.

here's some pics.
http://i121.photobucket.com/albums/o224/hbamps/top-1.jpg
http://i121.photobucket.com/albums/o224/hbamps/under.jpg
http://i121.photobucket.com/albums/o224/hbamps/upside.jpg

can anyone help?

thanks!

[GibsonGM]

Hey Johnny,

Have you read the post at the top of the forum called "Debugging - what to do when it doesn't work"?  Lots of advice in that one! 
Some hints to get you started:

-Is the switch connected correctly?
- I can't see well enough in the pic, but your "-" battery terminal is the one going to the input jack, and NOT your "+", correct?  It looks like those may be backwards...seems like your board ground (-) is connected directly, and should be switched by the input jack.
-Does everything that needs it have voltages? Measure and record these values for help in the forum.  Are all parts that are s'posed to be grounded, grounded?
- Have you audio probed the circuit from input to output? (search "audio probe" for more info on how to do this)

This should get you started, along with a good read of the debugging page.  If you can't find the problem, post back and people will help you.  We just need more info.  9 in 10 problems are pilot error, solder shorts, things like that.  Good luck!   

[zjokka]

best case scenario when only sound on bypass: you switched input and output!
but might be a lot more. do check this first.

otherwise:
-check whether you're circuit's getting power with the multimeter
-connect a alligator clip between in and output tip tabs
-if you are getting sound now, the circuit's ok, the problem is in the switching

if still no sound, start debugging with the audio probe.
good luck

zj

[johnny5]

thanks for the tips.
i did not have a DC adapter so i tried to wire it up without it until it got here in the mail. I see what you are saying, it should be switched, but i don't think it would cause a short, it seems it just makes the battery "on" all the time. i will fix that.

the battery + goes to the indicator LED and the board + for the above reason (skiping the jack). is that a problem?

I was probing voltages and found something weird. looking to see where i'd see 9-V. i noticed i have 9V on all three legs of the FET. I disconected power and continuity between them, they seem to be shorted. i figured maybe i have a ad FET, took it out and the empty three holes are still shorted. I am looking all over this board and just can't see anything. I know i'm missing something, just can't find it yet.

I read the debugging page and i plan to make an AUDIO PROBE tomorrow. I am going to try to prepare a voltage chart today.

thanks,
John

Hey Johnny,

Have you read the post at the top of the forum called "Debugging - what to do when it doesn't work"?  Lots of advice in that one! 
Some hints to get you started:

-Is the switch connected correctly?
- I can't see well enough in the pic, but your "-" battery terminal is the one going to the input jack, and NOT your "+", correct?  It looks like those may be backwards...seems like your board ground (-) is connected directly, and should be switched by the input jack.
-Does everything that needs it have voltages? Measure and record these values for help in the forum.  Are all parts that are s'posed to be grounded, grounded?
- Have you audio probed the circuit from input to output? (search "audio probe" for more info on how to do this)

This should get you started, along with a good read of the debugging page.  If you can't find the problem, post back and people will help you.  We just need more info.  9 in 10 problems are pilot error, solder shorts, things like that.  Good luck!   

[GibsonGM]

Well, what I was sayin' Johnny, if this is a Negative ground circuit, it looks to me like you have your battery V+ connected to your input jack (or maybe are just using opposite colored wiring??).....that would not be a very good thing    But I can't see enough in your pics to really know for sure. 

Running to the LED first is ok only if you're not putting it in SERIES with the power supply, which would cause a voltage drop in your power supply.   I always leave the LED out until I have everything debugged.  It's on a separate set of lugs in the bypass switching anyway...

A quick test of your power supply rails:  Check for continuity between your 2 power rails with your DMM - just check cont. between plus and minus where they enter the board, with no power applied.   If you have cont., you have a short between + and - somewhere, which I would assume you do if the FET is shorted!  Putting another FET there before fixing this will kill it if you apply power to the ckt.   99% of these problems are solder bridges that cause shorts, they can be hard to see. The above test can't find them all, if they're isolated by capacitors.  You'd need to examine the board closely and make sure there aren't any.  For sh*ts and grins, make sure the IC is in its socket the right way, too.  And check IC socket for solder bridging. 

For this reason, I always populate a board, leaving tails where off-board connections go (except for control pots).   I wire up the power and jacks directly with jumpers, test the effect, and if it works ok I then wire in my switch and LED, eliminating the board as a cause for failure...hope we're pointing you in the right direction!
Keep at it, you'll get it going 

[johnny5]

GibsonGM,
thanks for all the tips. I FIGURED OUT THE PROBLEM LAST NIGHT!!!!! I had a solder bridge on one of the traces that ran very close to 3 solder points. It was shorting out 3 lines (all connected to the FET). I cleaned up the joints (removed some solder and used an Exacto knife) and the pedal came to life! I am accoustomed to building amps where much more solder and bigger tips are used..

what really helped was to take a break and come back to it later with a fresh head.

I guess you looked at the pics incorrectly. the positive side of the battery is hooked to both the LED positive and B+ on the board. the negative of the LED is hooked up to the switch. I hooked it up per the GGG layout.

This pedal ROCKS! I am very pleased with it's first run. it has a very cool voice with good string to string articulation and backs off well without sacrificing too much compression. you guys should try it.

I think i want to try a BSIAB2 next.

[GibsonGM]

Must've been the red wiring in the pic, it was hard to see what was going where, lol.  I use a lot of black or green, and reserve red only for power; orange for signal.   Each finds their own way to do it!   Glad you got it up and running!  Almost always it's something we overlook like that; it's just so hard to believe there's a short when you KNOW there isn't, have checked it 100 times!     The fresh start after a break is a great idea, has helped me many times.   Enjoy your pedal (maybe I'll throw one together to see how she sounds...)