I Think I Found the Problem

texstrat · January 13, 2011, 11:48:33 AM

Quote from: milosch on January 13, 2011, 09:11:52 AM
On the DC jack it appears that the tip is wired to ground. Is that on purpose (negative voltage on tip) ?

This Fuzz Face clone is using PNP transistors and is (+) ground

twabelljr · January 13, 2011, 02:05:51 PM

I think the only voltage on the tip should be ac voltage from your guitar when you play. The tip is for audio signal no matter the polarity of the circuit. Right? With a cable plugged in to the input and output, do you measure dc voltage from tip to sleeve of the unplugged end of either cable?

Jhouse · January 13, 2011, 02:14:29 PM

Yeah. The tip is strictly for audio.

texstrat · January 13, 2011, 02:18:47 PM

Quote from: twabelljr on January 13, 2011, 02:05:51 PM
I think the only voltage on the tip should be ac voltage from your guitar when you play. The tip is for audio signal no matter the polarity of the circuit. Right? With a cable plugged in to the input and output, do you measure dc voltage from tip to sleeve of the unplugged end of either cable?

Grounding to the DC ground or jack?

Kinetic · January 13, 2011, 02:40:08 PM

I'd take the entire circuit out of the enclosure, so you can eliminate all possible shorts relating to the metal of the box. Then re-test.

texstrat · January 13, 2011, 03:15:02 PM

Removed everything except the dc jack, its plastic, and still the same problem exist. Just so I understand, if a short exist, would it not make the battery warm/hot? I have dealt with a short during the build and the 9V got very warm. What else might cause the voltage to drop and then settle?

Govmnt_Lacky · January 13, 2011, 03:46:06 PM

Just a shot in the dark however...

I breadboarded a PNP fuzz recently and had ALL KINDS of problems with oscillation, low volume, wild voltages, etc.

Turns out.... I had tapped the input AND the output to the same row in the breadboard!

I never thought to look for this because the circuit KINDA worked.

Good Luck

texstrat · January 13, 2011, 04:00:28 PM

Quote from: Govmnt_Lacky on January 13, 2011, 03:46:06 PM
Just a shot in the dark however...

I breadboarded a PNP fuzz recently and had ALL KINDS of problems with oscillation, low volume, wild voltages, etc.

Turns out.... I had tapped the input AND the output to the same row in the breadboard!

I never thought to look for this because the circuit KINDA worked.

Good Luck

I about ready to call it quits on this and send it back to GGG. This has been a pain in the a$$ since the get-go. I can fix a tube amp, but I cannot run down the gremlins with this project.

runmikeyrun · January 13, 2011, 04:11:48 PM

Quote from: danielzink on January 13, 2011, 09:02:19 AM
Quote from: texstrat on January 12, 2011, 10:58:34 PM
Pulled the jack out and still the same issue. I have power to both sleeves 8.93V, but probing the input tip the voltage starts at 8.45 and drops to 8.00. I get nothing on the output tip back to the switch.

Someone correct me here - but sleeves are ground - no ?

I wouldn't think there should be any voltage on the sleeves.

Dan

Right, you should have continuity to ground with the sleeves, no continuity to 9V, and def no voltage on them! Check your power wiring... do you have a multimeter that goes "beep" when you have continuity? You should have no beep between 9V+ on the battery clip and the sleeves on your jacks. if you have a beep you've got a short, or its wired wrong, maybe backwards.

Cardboard Tube Samurai · January 13, 2011, 04:17:23 PM

I'd suggest that anyone attempting to help debug this should go and read the other thread where several people have tried to nut it out

Cardboard Tube Samurai · January 13, 2011, 04:22:09 PM

Quote from: milosch on January 13, 2011, 09:11:52 AM
On the DC jack it appears that the tip is wired to ground. Is that on purpose (negative voltage on tip) ?

To clarify my previous post, I asked this question in the other thread but he's adamant that he has the DC jack wired correctly. Still looks wrong to me too

Cardboard Tube Samurai · January 13, 2011, 04:26:32 PM

Also, have you tried replacing the transistors yet, just in case you happened to kill one when they were oriented incorrectly?

Jhouse · January 13, 2011, 04:32:52 PM

QuoteTo clarify my previous post, I asked this question in the other thread but he's adamant that he has the DC jack wired correctly. Still looks wrong to me too

It's because his pedal is using PNP transistors and a positive ground.

Govmnt_Lacky · January 13, 2011, 04:41:53 PM

The ONLY thing that stands out to me would be to check and make sure your input jack is wired properly. It is easy to get the RING and the TIP solder points confused.

Jhouse · January 13, 2011, 04:48:32 PM

If I get a chance, I'm going to throw one of these bad boys together tomorrow and see how they work. Texstrat's problem has really been bugging me lately. $:-\$

QuoteThe ONLY thing that stands out to me would be to check and make sure your input jack is wired properly. It is easy to get the RING and the TIP solder points confused

But it passes signal when the pedal is bypassed. It couldn't do that if you had the jacks messed up, right?

texstrat · January 13, 2011, 05:26:01 PM

I do have an audible continuity tester and neg. probe on ground and touching pos. probe to neg. on battery and dc jack, I get a beep. Testing the lugs on both the input and output jacks I get no tone. That is checking with the effect on.

I checked to be sure that I wired the jacks correctly, sleeve, ring, tip and those are correct.

It plays in by pass, the LED lights up when the switch is pushed, I thought I had wired the switch wrong, but looking at some other DIY sites, it looks similar. And more importantly, I followed GGG layout per the instructions on his site........

Jhouse · January 13, 2011, 05:31:36 PM

Swap out your transistors* and see if that makes a difference. Didn't you say that you had extra in the other thread?

twabelljr · January 13, 2011, 05:32:32 PM

QuoteGrounding to the DC ground or jack?

Grounding to the cable sleeve. Plug the cable in to the jack, then measure from the tip to the sleeve of the other end of the cable. The end that would plug into your guitar and/or amp.

QuoteBut it passes signal when the pedal is bypassed. It couldn't do that if you had the jacks messed up, right?

I was thinking the same thing earlier. The voltage (or whatever is wrong) must be getting there or happening when the effect is turned on. Good idea recommended to put two new transistors in. Simple enough test.
I see you live in VA texstrat, I live in MD. This is so intriguing I say bring it over and we can fix it! I am gonna print and study these pictures. Got recent pics of both sides of circuitboard and offboard wiring since you have been attempting repairs?

texstrat · January 13, 2011, 05:57:49 PM

Quote from: Jhouse on January 13, 2011, 05:31:36 PM
Swap out your transistors* and see if that makes a difference. Didn't you say that you had extra in the other thread?

GGG set new components and I just put the new set in and no change.

texstrat · January 13, 2011, 05:59:25 PM

Quote from: twabelljr on January 13, 2011, 05:32:32 PM
QuoteGrounding to the DC ground or jack?
Grounding to the cable sleeve. Plug the cable in to the jack, then measure from the tip to the sleeve of the other end of the cable. The end that would plug into your guitar and/or amp.

QuoteBut it passes signal when the pedal is bypassed. It couldn't do that if you had the jacks messed up, right?

I was thinking the same thing earlier. The voltage (or whatever is wrong) must be getting there or happening when the effect is turned on. Good idea recommended to put two new transistors in. Simple enough test.
I see you live in VA texstrat, I live in MD. This is so intriguing I say bring it over and we can fix it! I am gonna print and study these pictures. Got recent pics of both sides of circuitboard and offboard wiring since you have been attempting repairs?

I appreciate the offer and can meet you where ever.

News:

I Think I Found the Problem