My Fuzz Has Died

[afrogoose]

Hey Everyone! 

I built a GGG late 60's Fuzz Face.  It was awesome (past tense).  Last week I was changing the battery (it was still plugged in and switched on) and when I was trying to plug in the new battery, I was trying for a second or two to plug in the battery backwards.  (I have an embarrassingly difficult time differentiating the different terminals on a 9 volt battery after all these years).  I really wouldn't have thought that that could do anything negative, but when I did plug the battery in the right way, I got that dreaded burning smell from the pedal, and the LED wasn't lighting up.  When switched on, the fuzz still makes some sound, but it's very faint.  The bypass works fine.  Additionally, the battery gets really hot.

I thought maybe there was a short somewhere, but I can't seem to find it.  I also thought I might have fried the Ge transistors, but I swapped in some PNP Si ones and still it's not working.  Is it possible one of the electro caps got fried from me plugging in the battery backwards?  I actually have a reverse polarity diode in the pedal, but I'm not sure if I wired it the right way, or if polarity is even an issue at all.

I was hoping someone might be able to help me understand where I should be looking for a solution.

Thanks!!!
Andrew

[Codeman1407]

I would try replacing the diode and the power cap, (D3 and C6, i believe, based on this: http://generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a) and see if this solves your problem. If so, they did their job! Good luck!

[knutolai]

The rectifier diode should be connected with the anode to ground, if placed in parallel, or the anode to +9V, if placed in series:

Like this

[bluebunny]

I'd check again for a short.  Hot battery is a pretty good clue.  Check for continuity across the battery terminals (without the battery attached).  I guess you may have made a short by nuking something - like diodes and electro caps that the fellas have already mentioned.

[afrogoose]

Hey guys, thanks for all the quick replies!  I will definitely replace that cap and diode tonight.  And thanks for that advice, I will be sure to orient it correctly.  Hopefully this works!

[afrogoose]

Since the pedal has been working no problem for about a year, and all I did was open it up and change the battery, I thought it would have to be a real basic short, like a pot touching the case or another pot or something.  I took everything out of the case and laid it out and still no luck.  I also checked all the solder joints and still no luck.  Hopefully this works.

[therecordingart]

Check for continuity between the battery terminals. When you do that make sure you have a 1/4" cable plugged into the input of the pedal (if you used a TRS jack as a ground switch).

[LucifersTrip]

you're forgetting step one...take voltages

[afrogoose]

First a big thank you in general to everyone that offered advice in this thread, and specifically to Codeman1407!  I replaced the cap and diode and voilà, it works!  So I guess my takeaways from this learning experience are:

1. It's a good idea to wire in a reverse protection capacitor/diode in a PNP fuzz because apparently it's easy to *potentially fry those expensive Ge transistors you bought from Small Bear.
2. Always unplug/turn off your fuzz when you are changing the battery because connecting the terminals of the battery backwards for even a second or two can damage the pedal.
3.  DIYstompboxes.com is amazing.

[Codeman1407]

Awesome man! Glad I could help, my first solution suggestion on DIY! haha. Someone else would've said it if i didnt. These forums do rule!

Now crank up that volume and get fuzzy!