Low output and hot battery in PNP (-) grnd FF

[Joe Bonner]

I'm using the Tonepad PCB and layout to build a negative ground PNP Fuzz Face.

I'm getting extremely low output with this thing -- I had to turn my Vibrochamp up to about 8 or 9 to get any kind of sound out of it. I put my Bad Bob Bosster in front of it and had to turn the booster up to about 1:00 to get a decent sound.

Then I notice that the battery is getting extremely warm. I tried to get pin voltages from the transistors, but they are extremely low (in the .01 to .05 mV range). This byt the way, was with a battery that read about 9.0X volts. After about 5 minutes of trying to measure voltages, it was down to around 7 volts.

I've double checked my connections, inspected the board to make sure there are no shorts, and everything looks OK.

Any suggestions?

Thanks in advance.

Joe

[Lonestarjohnny]

With pin voltage's it would be easy to tell more what you have going on, but with it killin the battery that makes it tuff for ya, but my first guess would be to check the pinout's closely on your transistor's, and make sure each lead is tied to the correct point on the board. and make sure your lookin at the correct data sheet for the brand of transistor's you have, the brand is what you need the data sheet for, i have seen different pinout's on the same no. transistor, and the only difference i could see was the brand name.
Johnny

[petemoore]

I'm using the Tonepad PCB and layout to build a negative ground PNP Fuzz Face.
 >>using PNP transistors...[?] Orientation verified?

I'm getting extremely low output with this thing -- I had to turn my Vibrochamp up to about 8 or 9 to get any kind of sound out of it. I put my Bad Bob Bosster in front of it and had to turn the booster up to about 1:00 to get a decent sound.
 >>>Should Have good output.
Then I notice that the battery is getting extremely warm. I tried to get pin voltages from the transistors, but they are extremely low (in the .01 to .05 mV range). This byt the way, was with a battery that read about 9.0X volts. After about 5 minutes of trying to measure voltages, it was down to around 7 volts.
 >>>Battery should last much longer, check for shorts or very low resistance between the battery clip - and +  ?
 There has to be a miswire, or short somewhere, these voltages are nowhere near bias range.
  DMM black to ground in beep mode, check for stray ground everywhere except where ground should be.
 ..Just for kicks you can pull the transistors, and measure resistance of resistors on the board, if you read a lower than what it should be resistance reading on a resistor, disregard it or determine if there's an alternate path for current to travel through the circuit, ... Iv'e 'ballpark' calculated misvalue resistors and other problems this way. I'd Triple check the color codes first tho.

I've double checked my connections, inspected the board to make sure there are no shorts, and everything looks OK.

Any suggestions?

Thanks in advance.

Joe

[Fret Wire]

Joe, if your battery is getting hot, you have a short. Check your off board wiring, especially the jacks and switch. Also, check the board to see if you have the jumpers correct. That board is set up to go pos or neg ground depending on jumper placement. Are you using one of Tonepads wiring layouts?
http://www.tonepad.com/getFile.asp?id=76

If you can't find the short, remove all the off board wiring and just hook up the battery to the board. If your battery doesnt heat up, and you get normal voltages, then you know it's the offboard wiring that's the problem.

After that's all straight, you may encounter another problem. Sometimes a PNP fuzz will oscillate when wired for neg ground. If it does, the only solution is to go pos ground. I'm bringing this up because if you have ocsillation problems, plus wiring problems, it will make it harder to debug. So make sure your soldering and wiring are straight first.

[Joe Bonner]

Thanks for the replies! Just to clarify a few things I forgot to mention, I'm using Ge trannies from Small Bear, with the resistor values that Steve provided. I double checked the color codes last night (and I measured them before I put them on the board), but I'll check again. And I am using the PDF layout from Tonepad; jumpers seem to be correct.

I am pretty confident that I got the orientation of the trannies correct, but I will look at those again.

Thanks for the tips on hunting down a short. Hooking up just  a battery sounds like an excellent idea.

I'll report back when I get this thing figured out.

Joe