HELP!!!

[theaxeman]

Hi

I recently built a fuzz face clone (ge transistors from small bear), firt i tested the transistors by putting their un-cut leads into the transistor sockets and the effect worked, after i had cut the leads it stopped working. But then i found a cold solder joint on the base of one of the transistors, so i took the board out and fixed it. When i put the board and transistors back in it didnt work. I have checked for dry solder joints with my DMM and there dosnt apear to be any. What could be the problem?

[R.G.]

It could be a lot of things.  There's no way to tell from what you've given us.

Use your meter, read the DC voltages on the battery and all the transistor pins, and post them back here.

You've probably missed the 83 previous discussions of almost exactly this content, or reading the effects debugging page at GEO, or the debugging page here, or the other 83 solutions.

[theaxeman]

Hi again

I have tested the transisitors, one of them is ok (reads open across Emitor and collector both ways) the other is broken i think, it dosnt read open across the Emitor and collector, is it faulty? Also do you think I will beable to buy a set of transistors which will mach the existing resisitors i have on the PCB?

[petemoore]

Ask Steve at Small Bear about the other matched transistor, if it's Q2, anything in the ballpark should work, given there's the bias trimmer on it's collector?
 I use 2N3906's for pretesting FF's, that way I can blow them up till the circuit's right, and get 15 more for 2.49 at RS.
 I use DMM:
1   Beep mode [look for cold solder, continuity to Batt+/-..etc.]
2  *Resistance testing
3   Voltage reading
 ..*If you pull the transistors, you can figure out which resistors only have one path [if you test the R value with the DMM] through the circuit, I think that's all of them...look for the alternate path, that you're not testing it's R value, which would read lower R value than you're looking for in that in circuit resistor.
 In beep mode you can test every connection, easier if a little DMM probe access is left....I leave a little lead from components above board so I don't have to try to test contituity from under/over the baord.
 Voltage readings will usually find the problem very quickly, the solution could take more time, and creative efforts.

[Fret Wire]

You mention trying the trannys in sockets, then you stated you had a cold solder joint on one of the transistors. Did you mean one of the socket pins? If not, you may have heat damaged the tranny. It worked, then you took the board out of the box, and it didn't work. Check that nothing on the board is shorting on the box, or that you may have pulled some wiring loose when you removed the board.

[AL]

Have you built the audio probe at GEO? I can't say enough about this thing - it's a very quick/easy build and extremely useful. I use mine ALL the time. http://www.geofex.com/tektips.htm

AL