PLEASE HELP ME WITH MY SUNFACE/FUZZFACE!!!!!!

[sixstringuru]

Hello,
Can anyone tell me what looks wrong with my fuzz??? Both channels work, both on and off, but when on, it is a volume boost and no more. NO fuzz. Neither of the potentiometers work! and I cannot get the trim pot to alter the transistor voltage more than 1 volt. I can go between 7.5 and 8.5 only when it should be at about 4.5. PLEASE help guys!!
Pics are on the link!!

http://s44.photobucket.com/albums/f5/sixstringuru/
http://s44.photobucket.com/albums/f5/sixstringuru/

[burnt fingers]

I can't really tell for sure but one of the photos looks like you have some solder crossing traces on the back of the board.

Scott

[sixstringuru]

Nope. There are no solder or frays shorting. Next idea? It's really bugging me!

[pyrop]

Ok. looks as if you may have some bad solder joints. Some of them look a little big and may be shorting with parts of the board they shouldn't be.
Go over and clean up your solder joints and make sure you have no solder bridging.

I cannot get the trim pot to alter the transistor voltage more than 1 volt. I can go between 7.5 and 8.5 only when it should be at about 4.5.

That trimpot is probly 1k which will probly give you a 1 volt drop over its range so that means there is something wrong with R25 the 10k resistor i.e solder bridge at one end.

pyrop  

[sixstringuru]

Hey Pyrop,
Fixed all solder joints and still nothing. No shorts either. Is the wiring correct? What else do you think it could be??

Thanks a million

Mike

[Dai H.]

Ok. looks as if you may have some bad solder joints. Some of them look a little big and may be shorting with parts of the board they shouldn't be.
Go over and clean up your solder joints and make sure you have no solder bridging.

I cannot get the trim pot to alter the transistor voltage more than 1 volt. I can go between 7.5 and 8.5 only when it should be at about 4.5.

That trimpot is probly 1k which will probly give you a 1 volt drop over its range so that means there is something wrong with R25 the 10k resistor i.e solder bridge at one end.

pyrop  

that's what it looked like to me too (poor soldering). Who did the work? Kind of sloppy looking. Also, are you a good solderer and did you heatsink the transistors before re-doing the joints?

[petemoore]

  Before soldering, what to solder/unsolder needs to be determined, finding which traces on the board relate to the schematic [schematic?] and if there are any stray connections.
  I didn't look at the pics but trust there's something looks funny. That, combined with the 'funny' way the knobs don't work is a near sure tell of miswiring of some kind.
  At this point I'd consider a thorough going over of the board with a multimeter to see if an 'anomolous juncture' like solder bridge can be found as cause of the circuit malfunction.

[The Tone God]

Fill out the "What to do when it doesn't work" sticky and report back.

Andrew

[sixstringuru]

Hey Guys,
I did not solder the transistors. Analog Mike put in all components and only soldered in the transistors. I did the rest. I re-soldered everything and still same problem. A huge volume boost and thats about it. Its really bothering me considering the transistors cost me $100.

Please tell me what you would like me to do.

[jrc4558]

Hey Guys,
I did not solder the transistors. Analog Mike put in all components and only soldered in the transistors. I did the rest.I re-soldered everything and still same problem. A huge volume boost and thats about it. Its really bothering me considering the transistors cost me $100.

Please tell me what you would like me to do.

I dont know your soldering skills, likewise I am not exactly sure what do you mean by saying: "I re-soldered everything". If you indeed resoldered everything, you could have burned your transistors.

[barret77]

Its really bothering me considering the transistors cost me $100.

? $100 transistors ?

[Dai H.]

$100 (or whatever out of the ordinary prices) for rare old stock NKT275s and parts like that which are found in vintage equipment. I would not recommend soldering anything hard to replace like that without heatsinking and much care. It's not like you can go down to the electronics store and get a replacement. It makes me feel very ill when I do something like crack an old tube... 

[aron]

It sounds like a miswiring or some problem with bad soldering. You need to follow this:

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

and approach this in a logical fashion using a meter and do you have the schematic?

Aron

[Ed G.]

Q7 looks like it's not soldered in well at all on at least one of those legs. Use something to draw heat away from the tranny, like a hemostat (they're not just for smoking weed anymore)
It's a fuzz face, not that much to go wrong with it.
$100 for a pair of transistors. Now don't that beat all?

[Dai H.]

another thing is that the leads on some of the old parts may have been oxidized, and this wasn't removed before soldering. Might be good to remove parts and clean the leads before resoldering in such a case to make sure the solder "takes".

[R.G.]

So far, this is a good example of what happens when you don't follow "What to do when it doesn't work".

All the speculation and inspection you'd care to do will not tell you much until you do the electrical measurements to tell you what it's really doing inside.

"What to do when it doesn't work" is a necessary first step unless you already have a lot of experience.

[the dude]

I know what's wrong!!! Not enough people responded to your help call, maybe another dozen people need too respond