germanium tone bender MKll update, new problem

[nag hammadi]

okay guys.  here is where i stand.  in my last post, i was getting nothing but a very hot battery when i turned the pedal on.  the general consensus was that there was a short somewhere.

well, i finally realized my dumb mistake - i had placed a jumper at the wrong place, causing the short.

now, i am not getting a hot battery, but a WAY WAY low signal.

did i fry something?

here is the layout i am following:

http://www.generalguitargadgets.com/diagrams/tonebender_m2p_lo_ng.gif

the only thing i have done differently was to omit the dc jack, led, and 4k7 resistor attached to the led.

i assume i should check for voltages, but i am unsure where.

help for a frustrated newbie would be greatly appreciated...

[nag hammadi]

by the way, this is an updated post... this posting with this pedal started with an entirely different thing, so i started a new post for the updated situation...

sorry if that causes clutter or confusion.

[nag hammadi]

 

i have replaced the battery as per someones suggestion, but to no avail.

here is a little more info.  bypass sound is fine.  effect sound is NO fuzz, but just a muffled tone about 1/5 the volume of my bypassed signal.

volume control does adjust volume, but attack control does nothing.

i am assuming i need to take some measurements, but i can't seem to get any pointers as to where to take the voltages from.

i am sitting here with the guts of my tone bender with my iron hot and my DMM raring to go...

PLEASE HELP!

[twabelljr]

    Since you have the link to the layout you used, make a list of all the components and connections as they are labeled on the layout. Then clip your neg. meter lead to ground and measure as outlined here:  http://www.elixant.com/~stompbox/smfforum/index.php?topic=29816.0
I'm not sure I'll be able to help, but with measurements and links provided, I'm sure will will get the help you need. Best of luck!

[nag hammadi]

name of project:  tone bender mkII professional with germanium tarnsistors as detailed here:

http://www.generalguitargadgets.com/diagrams/tonebender_m2p_lo_ng.gif

i have followed the layout exactly, with the use of the pcb that i ordered from ggg.  no parts were substituted.  the only difference is that i omitted the dc jack, the led, and the corresponding 4k7 resistor that went between them.  everything else is exactly as listed on the layout.

this is a negative ground design. 

i get a clear sound in bypass, but a very low muffled (no fuzz at all) signal when engaged.  i would say the volume is maybe 20% of the bypassed signal when engaged.  also, i get no response from the attack pot, but the voume pot does vary the volume when engaged.

on my first power up, i was getting nothing at all, except for a very hot battery.  i checked for shorts and found that i had place the jumper in the wrong place. i fixed that prblem, and now here i am...

my battery is good.

my head is clear (though some would say empty is a better word).   

i am measuring with battery connected, cable connected to input, effect engaged.. 
STILL not sure where i need to be measuring, but here is a starter list:

battery = 9.6 v
q1:
c= 6.16v
b= 5.91v
e= 0

q2:
c=3.94v
b=3.66v
e=0

q3:
c=4.11v
b=3.93v
e=.50v

i don't see any diodes on my layout.  the rest are pots, resistors, and caps...

can anyone help?

[newperson]

hi,
are the transistors in correctly?  the emitter for the US made ones (Q2,Q3) have the little tab marking it.  The Jap. made one (Q1) has an arrow pointing at the collector.

Are they put in like this?

-paul.

[formerMember1]

probably what the last post said about transistors, if not, sounds like you have it wired up wrong.

[nag hammadi]

hmmm....

i guess i did have the 1st transistor  (the jap one) in wrong.  strange how it is th opposite o the hole pattern on the layout.

at any rate, i made that change and there is NO change in the effect.  i am still getting nothing but VERY low signal when i engage the effect.  still no effect by adjusting the atack pot, still changes in volume with the volume pot.

new voltage ratings:

q1
c=1.17v
b=1.48v
e=0 still

q2
c=3.87v
b=3.6v
e= 0

q3
c=4.05
b=3.88
e=0

am i supposed to get 0 from the emmiters?  that doesn't seem right, but no one has mentioned it as being indicative of anything yet...

i am at a complete loss.  i have checked and rechecked the wiring, and even had someone else check the wiring, and it seems to be wired properly.

does anyone have a CLUE as to what else could cause this?

[newperson]

hi,
i measured one of mine. not the same layout as yours but the same MK2 tonebender effect.  i get 0 volts to the Q1,2 transistors and some voltage on Q3.  look around Q3 for the problem.

I would check your wiring like the others have said.  sometimes you can find something after looking many times.  i would also go over all the resistor values and make sure they are correct.  i can measure again later tonight if you need something else. 
-paul.

[nag hammadi]

sooo...

after two weeks of beating my head against the wall trying to figure out what went wrong with this pedal, i finally have it figured out.   

turns out, small bear sent the wrong transistors!  i sent the drawing for the pnp circuit, and they sent npn resistors...   

so i reversed the polarity of the PS, electrolytics, etc... and now i have a lovely tone bender.

i guess it goes to show that SOMETIMES you can check your work a million times, but the problem is something you would have never expected.

no offense to small bear at ALL, but i sure would have liked to have known that last weeek!