hello and help with GGG fuzz face 60's version

[kbob]

Hello all,
New person to the forum here, just starting out with making my own electronic gear.  Made an acoustic guitar from a Stew Mac kit a few years ago and decided to try my hand at electronic stuff.  Made a copy of the fender delux from a Mike Marsh kit last year and that went very well so thought I'd try a Fuzz face kit.  This hasn't gone as well so far.

First I have very little self taught knowledge of circuits so please bear with my ignorance. I assembled the kit as per the layour here with no known alterations on my part:

http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

The transistors I used were marked as NPN by the kit package but they are silver with the numbers "CEN 2N2369A" inscribed on them instead of "PN2369A" as indicated on the package label.
all the wires look to be correct as per the diagram and solder joints appear to be clean and silver, not gray.
When I plugged in and turned the unit on the volume was markedly decreased from the amp and with all knobs in the max position there was minimal distortion effect.  The contour knob produced a lot of static when turned.  all other knobs were silent when turned.
I measeured the values of all resistors and they are correct.  When I turned the unit on today to meaasure E, B and C values (as per the sticky in this forum) the LED light did not light up - it did yesterday.
Values at Q1 are E=0, B= - (negative)5.0 and C= -4.3.  Q2 are E= -0.28, B= -5.0 and C= -5.65 with the trim pot all the way counter clockwise.  Yes these are all negative numbers.  The black lead from the multimeter was touching the ground terminal of the output jack, there was an instrument cable plugged into the input jack.

I had a home electrician and an EE neighbor look at the thing and they didn't see any obvious errors and the wires looked like they all connect as per the diagram.

Any thoughts on where to look next?  I know this will take some work and I'm willing to look where you guys tell me but I must admit I have little experience with electric equipment so if you please write in laymans terms I'm happy to work through this and know it will ultimately work.

Thanks a lot folks.

[rousejeremy]

Do you have the positive wired to ground and the ground wired to 9v in?

[Govmnt_Lacky]

First and foremost, if you wired your circuit like this:

http://www.generalguitargadgets.com/pdf/ggg_ff5_lo_b69.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

Then that is your problem. This wiring is for PNP Germanium transistors. The numbers you stated above are for NPN silicon. If you are indeed using the 2N2369A transistors, and you wired your circuit like above, then all you SHOULD need to do is swap the V+ and the Grounds.


Well.... that and hope you did noy fry your silicon transistors. 

[Govmnt_Lacky]

According to the layout that you posted above, do the following:

1) Remove the wire going from the upper DC jack lug and the Input jack RING.
2) Desolder the Battery negative lead from the DC jack and install/solder it to the Input jack RING.
3) Desolder the wire going from the 9V circuit board pad to the DC jack (DESOLDER DC JACK SIDE ONLY!)
4) Place desoldered end of wire in Step 3 into empty lug of DC jack from Step 1 and solder.

I believe that ALL of your electrolytic capacitors and your diode will need to be "reversed" as well.

Provided you did not fry any components, this should do it. 

[rousejeremy]

Or you can wire it like the GGG 70's fuzz.

[kbob]

Thanks guys,
I also got PNP transistors in the klit - should I just try using them?  or should I try the 4 step program from Govmt lacky and hope the components work

The other instructions from the website said that the circuit was originally for a positive ground but they changed it due to oscillation problems when run off of AC so I assumed (probably shouldn't have done that) that the posted wiring diagram was for a negative ground. (see what happens when you don't know what you're doing!).
Thanks again

[Govmnt_Lacky]

Bottom line is that according to the layout post you had earlier, the wiring is set up for a POSITIVE ground. Meaning that the battery/DC jack is sending V+ to the ground rail and the battery/DC jack ground is going to the 9V input. This is what is SUPPOSED to be the setup for the PNP trannys. Your NPNs are not going to work in that setup. So... you can either:
1) Redo the wiring as I described and use the NPN trannys.
2) Keep the wiring as is and try out the PNP trannys.

Either way I STRONGLY suggest you do two things.

1) Read JDs Fuzz Face instructions.
2) Scrutinize your build over and over again BEFORE putting in the PNPs. If they are Germanium, you do not want to blow them up because of simple wiring or soldering problem.

Either way... Good Luck 

[kbob]

OK -I will re-wire as per your instructions for a negatiev ground.
While I have the caps, transistors and diode out is there any good way to check them to see if the are still functional while I have them out of the board?

Also another disturbing thing is that the LED light worked initially but now does not.  Is this a bad omen?
One thing about trying to make your own stuff is that you gain a lot of respect for the folks who make them everyday and make them work well.

Thanks a million guys.

[Govmnt_Lacky]

When an LED is bad you can USUALLY tell because it is either dirty yellow or burnt black inside the lens.

As for the caps, other than a resistance check, I do not know how to check them for proper capacitance.

The diode is easy. Use a DMM on the diode setting and read it out.

Best bet would be to replace the LED and caps just to be sure.

[kbob]

GovmntLacky-
Looked at other wiring diagrams from GGG and Re-wired as per your instructions for a negative ground.
Did have to add an additional ground wire from the ground strip to the adapter input jack.
Plugged in the NPN transistors and it worked!
The LED still doesn't function but is easily replaced.

Now What to do next- learn more about circuits and components.

Thanks again folks - you're a great help.