Troubleshooting GGG Ciwil War Muff

[VPIF]

Hi, guys. Having some trouble with my latest build. Probably a stupid amateur mistake, but nonetheless:

1. Bypass is fine. No light in led, no sound when acivated.
2. GGG Big Muff - Civil War Russian version.
3. http://www.generalguitargadgets.com/pdf/ggg_bmp_rusc_sc.pdf
4. No modifications.
5. Parts substitutions: All transistors are 2N5088 instead of 2N5089.
6. No positive ground to negative ground conversion.
7. Battery voltage: 8,82V
Voltage at the circuit board end of the red battery lead = 0,13V
Voltage at the circuit board end of the black battery lead = 0,0V

Q1
C = 0,12V
B = 0,70V
E = 4,44V

Q2
C= 0,12V
B= 0,70V
E= 4,50V

Q3
C= 0,11V
B= 0,69V
E= 4,39V

Q4
C= 0,89V
B= 1,37V
E= 8,79V

D1
A = 0,46V
K = 0,70V

D2
A = 0,70V
K = 0,46V

D3
A = 0,45V
K = 0,69V

D4
A = 0,69V
K =0,45V

Any suggestions will be greatly appreciated.

[VPIF]

Correction: Voltage at the circuit board end of the red battery lead = 8,80V

[Mike Burgundy]

First off: I think you accidentally got Emitter and Collector mixed up. Emitter is the one with the little arrow pointing out, and should be connected towards ground, collector towards supply (all through their respective resistors of course).
That said:
-subbing 5088 instead of 5089 is ok. In fact, AFAIK most people like lower gain (the main diff between '89 and '88) in a muff, you might want to try less Hfe when you've got it working, just to see what flavour that gives.
-Q1: voltages look ok, assuming C and E are accidentally swapped (what you're looking for is C somewhere in the middle of the supply, say between 3 and 6V or something, E close to ground, B a diode drop (0.6-0.7V) above E)
-Q2: ditto
-Q3:ditto
Q4:that ones a little high, at least B and E look ok. I'd expect the collector (8.79) to be lower though, looks like the transistor is (almost) completely turned off. Have a good look at that one, make sure your pinout is ok, if so, replace it. I think that might be your culprit: either its in wrong, soldering went wrong, or it got damaged soldering it in.

[LucifersTrip]

Q4:that ones a little high, at least B and E look ok. I'd expect the collector (8.79) to be lower though, looks like the transistor is (almost) completely turned off.

that's an understatement. the collector is shorted to the 9V+ rail !

"Voltage at the circuit board end of the red battery lead = 8,80V"
Q4
C= 8,79V

[VPIF]

Thanks for the kind replies.

I had got collector and emitter mixed up, as pointed out.

Changed Q4, but the voltages are basically the same as before. I also checked the voltages on the LED. It stays around 0,06-0,07 no matter what position the footswitch is in. I have checked the circuit for shorts (visually) but haven't found any. Should the problem be somewhere around the collector on Q4, or could it be anywhere in the circuit?

[Pyr0]

If you are using one of the GGG PCB's for this, check the bottom of R24, this is the 10k resistor that connects the collector of Q4 to 9v, and the 9v track runs right next to that point so maybe you have a solder bridge there.

[VPIF]

I have checked the tracks around R24 several times - both visually (with a magnifying glass) and wtih a multimeter. There's no continuity between the tracks. I also checked all three legs of Q4 for continuity to ground, and (as long as the battery is attached) I found none.

[Pyr0]

Check the resistance between the collector of Q4 and the +9v connection.

[VPIF]

Allready on it There is continuity (wide open, no resistance) between the collector on Q4 and the 9V track. I can not find a solder bridge or any physical contact between the two tracks. I also measured R24. It should have been 10Kohms, but the meter shows no resistance at all. Seems unlikely that the resistor would be faulty, doesn't it?

[Mike Burgundy]

There's your problem. I highly doubt the resistor is a short, though, but hey, never say never. Lift one end of the resistor, and measure again, both the resistor and the tracks. Either one or the other will still show a short, or neither will. In the latter case, solder it back in and you may have "found" the short when unsoldering. If there still is a short, you'll know where to look. If it's the tracks, and you can't find anything, try scoring between the tracks with a knife to break any minute hairs of solder that might be there. Leftover flux sometimes makes tiny, tiny hairs of solder incredibly hard to see, while they still conduct just fine.

[VPIF]

And it works, and sounds great!!!

The problem was not the resistor, it was probably a tiny amount of copper bridging the tracks right by R24  Now the only thing that doesn't work is the LED. I will check the solder joints on it, and possibly cange it in case it has burned out.

Thank you so much to everyone who has contributed. I have actually learned something today, and I am grateful for that, and for my new awesome muff. It rocks, and so do you guys

[Pyr0]

Glad you got it working. Have fun