Hi.
I'm trying to figure this one out, but I'm kinda' stuck. Looks like Q2 is shorted to ground, but I don't get continuity with the meter... Any help will be appreciated.
1.What does it do, not do, and sound like?= Low gain, low volume, scratchy tone pot.
2.Name of the circuit = GGG big Muff – Civil War version.
3.Source of the circuit (URL of schematic or project) = http://www.generalguitargadgets.com/pdf/ggg_bmp_rusc_sc.pdf
4.Any modifications to the circuit?= No
5.Any parts substitutions? = No. Used 2N5089 transistors.
6.Positive ground to negative ground conversion? No
7. Battery voltage? = 9,01
Voltage at the circuit board end of the red battery lead = 8,89
Voltage at the circuit board end of the black battery lead = 0
Q1
C =0,13
B =0,72
E =4,45
Q2
C=0
B=0
E=8,78
Q3
C=0,12
B=0,70
E=4.29
Q4
C=0,92
B=1,40
E=5,36
D1
A=0
K=0
D2
A=0
K=0
D3
A=0,70
K=0,47
D4
A=0,70
K=0,47
You list all your Emitters at higher voltages. Did you transpose the numbers wrong OR do you have all of your transistors in backwards?
The transistors are put in as shown on the layout diagram on the GGG website. I found a website that says it's C, B, E from left to right on the flat side of the transistor. Maybe I should pick my sources more carefully :) The circuit is producing sound, allbeit low on gain and volume, so the transistors have to be in the correct orientation, I guess.
Short answer: It's pretty likely that I transposed the numbers in the incorrect order.
Quote from: VPIF on February 22, 2013, 01:41:54 PM
Q2
C=0
B=0
E=8,78
there's really nothing more to do until you sort this out. simply scrutinize the area around that transistor and get voltages close to Q3
Quote from: VPIF on February 22, 2013, 02:03:23 PM
I found a website that says it's C, B, E from left to right on the flat side of the transistor. Maybe I should pick my sources more carefully :)
If you are using 5088s, then you have them in backwards.
5088s are E, B, C from left to right with the flat side facing up and the leads pointed towards you.
(http://vakits.com/sites/default/files/imagecache/product_full/2N5088.JPG)
EDIT: I see above that you are using 5089s. Should be same pinout as I diagramed above but, I would go with 5088s if you want to stay true.
Thanks.
OK. I swapped the collector and emitter voltages, then. Got to remember which i which soon :icon_redface:
I will examine the circuit around Q3 in detali tomorrow, and report back. Now it's bedtime on this side of the Atlantic.
Thank you for your replies, kind Sirs :)
Ass-uming transposed:
> Q2
> C E = 0
> B=0
> E C =8,78
R10 470K is not really there; suspect bad solder joint.
Quote from: PRR on February 23, 2013, 01:02:34 AMR10 470K is not really there; suspect bad solder joint.
WOW! I wish I can do that someday. I know it's relatively simple circuit, but that's really impressive to me. You were, of course, spot on, and I bow my head in gratidute and respect.
I would like to thank everyone who contributed, before I go and bask in creamy muffiness :)
R10 pulls the Base up. Base is not up. Therefore R10 isn't doing its job. Since resistors rarely fail (without smoke), joints are first-suspects.