problems with TS808

[slim_blues_boy]

hello, I just build my first stompbox project, TS808.
but there are something strange with it.
the pots seems like not working, or maybe working but with very little effect.
there are only slight different between cranked volume/drive/tone pots and rolled down volume/drive/tone pots.
and the volume are small. 100% volume from my amp with that TS808 are same like 20-30% straight to amp volume.
I use layout from

Code Select Expand

www.tonepad.com, and use all components from the instruction expect the drive pot. I'm using A1M pot instead of A500K.
anyone have any idea with my problems?

thanks

[Auke Haarsma]

read and follow What to do when it doesn't work: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[slim_blues_boy]

ok, I already follow the instruction.

1.What does it do, not do, and sound like?
the stompbox has sound, but the volume are small. 100% volume from my amp with that TS808 are same like 20-30% straight to amp volume.
and the pots seems like not working, or maybe working but with very little effect. there are only slight different between cranked volume/drive/tone pots and rolled down volume/drive/tone pots.

2.Name of the circuit = Ibanez TS808

3.Source of the circuit (URL of schematic or project) = http://www.tonepad.com/getFileInfo.asp?id=81

4.Any modifications to the circuit? N

5.Any parts substitutions? A500K pot changed with A1M pot

6.Positive ground to negative ground conversion? N

7. Voltage measurement:

Voltage at the circuit board end of the red battery lead = 7.88
Voltage at the circuit board end of the black battery lead = 0

U1 Pins
P1 = 7.77v
P2 = 7.73v
P3 = 7.77v
P4 = 0v
P5 = 7.74v
P6 = 7.76v
P7 = 7.76v
P8 = 7.78v

Q1
B = 7.40v
C = 7.80v
E = 7.77v

Q2
B = 7.41v
C = 7.80v
E = 7.77v

D1
A = 7.74
K = 7.48

D2
A = 7.68
K = 7.72

I also noticed that the 10uF caps has same voltage on (+) and (-) pins, 7,74v. is that ok?

thanks for all help

[petemoore]

U1 Pins
P1 = 7.77v
P2 = 7.73v
P3 = 7.77v
P4 = 0v
P5 = 7.74v
P6 = 7.76v
P7 = 7.76v
P8 = 7.78v
  They're all near the supply rail, test that the voltage divider actually has 1/2v at the junction of the two equal value resistors.
Q1
B = 7.40v
C = 7.80v
E = 7.77v

Q2
B = 7.41v
C = 7.80v
E = 7.77v
  Breadboard comes in handy for this kind of buffer build/test, I don't think there's a bias association with the Vdivider, but these buffers both have the same bias trouble, look for something they have in common for reason either one is misbiased.
  Measure emitter resistor between transistor leg and Gnd...say at the chassis or other 'distant ground'...so you're actually testing connections as well as the resistor value.
 
   
D1
A = 7.74
K = 7.48

D2
A = 7.68
K = 7.72

I also noticed that the 10uF caps has same voltage on (+) and (-) pins, 7,74v. is that ok?
   It's not doing any capacitating like that, it's probably the other 'thing also making this kirkpacitor have near supply rail voltage.
  I think there's a ground connection N/C'd, First connect black lead to Gnd. and test every Gnd to make the DMM beep [following schematic grounding].
  Something's allowing the whole circuit to float up near the supply V, it needs a 'span' of most of the supply voltage so that it can amplify and swing the output voltage up/down.
  I would definitely check grounds and voltage divider, and as a routine, test other connections at the same time by picking the 'distant point connection' to probe [through as many connections/parts as possible per probe test].

[slim_blues_boy]

IT'S WORK NOW 
and the result is a damn pretty hot TS808 

like Petemore said, the problem was on ground connection.
I missed one connection to the ground when etched the pcb.
and I didn't realize it because my copy of layout printed badly so I can't check them clearly.
once I cross check again with the pdf file, I found the problem.
thanks Pete.