ts-808 debug

[jlullo]

hey guys...
i build a ts-808 for my guitar player, because he loves mine so much!  having some issues though.  When i play through it, i'm getting a fizzling, farty, splatty, gated sound.

I built it using the Tonepad layout:
http://tonepad.com/getFileInfo.asp?id=81

substituted parts:
2n2222a trannys
i have a dpdt switch wired to where the 0.047 cap is, switching between a .047 and a .22 cap

i'm getting really weird voltages.  I had my dmm set at 20k... why the hell are they so high when i'm using a 9v battery??  also, they were negative voltages??

IC1 -16.01
IC2 -16.24
IC3 -12.30
IC4 0
IC5 -15.19
IC6 -16.02
IC7 -1
IC8 -16.03

D1
a -16.21
c -16.05

D2
a -16.04
c -15.92

D3
a -15.92
c -16.24

Q1
C -15.1
B -14.41
E -1

Q2
C -14.54
B -14.45
E -1

any help would be greatly appreciated!

[jlullo]

i'd also like to add that i had to use the black lead to get a voltage reading (with red on ground).... why??

[QSQCaito]

You get negative voltage because you put the red(positive +) as ground.. being that circuit negativge ground. You SHOULD get voltages using it the other way round, black wire in ground.. Maybe you were doing false contact... Also for that weird voltages, measure your battery first. Happenned to me that as my DMM battery was dying, it measured what it wanted..

[jlullo]

QSQ, i couldn't get a reading the opposite way... i'll go check that battery and see what's up

[jlullo]

i just tested the battery in my DMM, and it was around 8V.. i switched it anyways, and i still can't get a reading.  why would this be?  my battery is hooked up correctly

[Torchy]

Why are you trying to measure voltage with your DMM set on a 20K resistance range ?

[jlullo]

that's how i've always done it... is that incorrect?

[Torchy]

that's how i've always done it... is that incorrect?

Yes thats incorrect. You are actually measuring the dc resistance of those points to ground with power applied. And that 'resistance' shown is the sum of the parallel paths to ground. With power applied you are also shunting the DMM. To measure resistance the DMM actually puts a small voltage across the probes (internally) to measure the resistance via a resistor bridge (google for Wheatstone Bridge). With the DMM set to 20K you are telling the DMM that you expect to see a resistance of 0 - 20Kohms between the probes. The range switch changes the value of resistors in the internal bridge.

Select a dc voltage range (say 20Volts), and recheck those points with the black lead to ground.

May be an idea to read the DMM manual as well ?

[jlullo]

i'm sorry torchy... i don't know what the hell is wrong with me today... i meant 20v (not 20k).  the enraged side of me took over reason

i saw a couple of blobby solder points, and retouched them.. everything is great now!  i'm getting correct readings...

this is the first time i've ever gotten a cold solder joint!  i have a feeling there were a few on the trannys and were the 9v supply actually went to the board.

everything is good though guys.  thank you for your help!

[jlullo]

wow.. i'm really psyched about how this one sounds.  i may have to build my self a new one!  Switching between these caps is fantastc!

i can't decide between the 2n2222a's and the bc109's though!  the 109's are a bit more gain, but the 2222a's sound so sweet