Well, here we go.... or, "it don't work."

Started by Celery_Strat, January 14, 2011, 05:55:19 PM

Previous topic - Next topic

Jhouse

I think it is an on board problem to tell you the truth. At 9 volts pins 1-3 of the IC should be about 4.5 volts (pin 3 seems fairly correct), pin 4 is grounded (correct), pins 5-7 should be about 4.5 volts, and pin 8 should be the full voltage (which is also correctly). On the transistors the C legs should be the full voltage (correct), B should be about 3 volts, and E should be about 2.5.

twabelljr

The level pot is connected to bias voltage too. Like you said, pin 3 is the only pin of the opamp that is even close to bias. I've never used an audio probe but that should reveal something.
Shine On !!!

Celery_Strat

The audio signal seems to stop after pin3 on the IC.  I'm not sure if that was tested correctly, but, each time i got no further than there.  I'm cross-eyed and the wife went to bed over an hour ago.  I'm defeated for tonight.  I'll get back on it tomorrow.  Thanks for the help so far, guys.  Good night.

petemoore

  What do all the stages have in common ?
  Misbias problem.
  What else do all the stages have in common ?
  Vbias reference voltage.
  What is the Vbias reference voltage in this case ?
Convention creates following, following creates convention.

Johan

there is no opamp in your picture!...is it there now?...I know its a stupid question, but we've all done that mistake a few times..
J
DON'T PANIC

Celery_Strat


Vbias measures at 4.81 volts.

Once again,  the picture IS NOT of my project.

petemoore

I plug the guitar into the input jack and, with the footswitch off, probe the tip of the plug in the jack, hear the guitar.  Now, click the footswitch, and no sound from the tip!
  See if the input jack tip isn't connecting to Gnd. w/stated^ footswitch position.
  Figure out ''if so/how'' if input grounding, where is the ground getting in there.
   
Convention creates following, following creates convention.

Celery_Strat

#27
It is.  The tip goes to ground when switched on.  But I swear the switch is wired correctly.
**EDIT:  stand by.  I think I've got it!***

Celery_Strat

Scratch that.  Fixed the grounded plug issue, but the thing still behaves exactly the same.  It's just short of going out in the yard...

petemoore

  But I swear the switch is wired correctly.
  BIStSiWC !
  wait...quick search of where I've seen that pesky, oh ya here it is.
 K,,,visual/DMM search for ground entry point, dmm's useless expect after the ground isn't an entry point, it'll tell you that but not where the dern Gnd 'leak is before it's found, BTW remember what you did right before the frequent DMM check that made the ground disappear from the leak-point, that way you might know where it was to better eliminate it. An excess of trevails between gnd. checks may mask where the problem became located, once fixed it would become a reverse process with the DMM, creating the unwanted gnd...just to find it !
 So that leaves pretty much visual and logic. Visual for me improves w/close in Hintensity lamp and mag-glass.
 The Logic of the switch is:
 Throws   l   l   l
 Poles      l   l   l
 Throws   l   l   l
 or:
 if the switch body is turned 1/4 turn:
 Throws    Poles   Throws
    J_      _       _Jumper
   JI_      _       _OJ
  eI_      _       _eO
  ..the orientation I prefer, J-Jumper would be bypass wired lugs, JI for goes to input jack, OJ for goes to output jack, eI directs JI to effect input, JO directs effect output through switch to output jack.
 But with switch, DMM and notepad, is worth the effort to map a DPDT or 3PDT at least one time to get an idea how to orient and where to look for connections through the P and T lugs.             
 Map the connections of the switch on paper, using DMM to beep when two lugs connect.
 DPDT = three simultaneously activating spdt switches.
 Three 'separate' spdt switches.
 1/3 of it is separate T-P t [throw>pole, unconnected throw=spdt].
 3 poles: each pole connects to 1 of the two throws it is centered between.
 Hit the switch 1 time.
 Make another map of the new set of connections the switch is making.
 
   
 
 
Convention creates following, following creates convention.

Celery_Strat

#30
EDIT removed due to mistake

Celery_Strat

Pete and everyone else,  I want to thank you for the effort you put forth, but I've disassembled the board, and the components are in a baggie.  I have built a tweed deluxe and a deluxe reverb clone.  This litttle thing has really worried me to no end.  Maybe the opamp is bad.  Maybe I overheated a component or two soldering.  I'll get back to it later.  Right now though, I'm off to order a greenie from guitarfetish.com.  thanks guys.

Quackzed

nothing says forever like a solid block of liquid nails!!!


Celery_Strat

Not sure what "generation Y" is, but if it's a stab at the kind of person I am, be careful.  I was letting this little thing have WAY too much of my time, and not enjoying it at all, nor was my family.  I prefer to enjoy my hobbies, so when the cussing starts, it's time for a walk.  I haven't given up on pedal building at all.  I have just put this thing aside for a few days.  I wasn't really ordering the greenie anyway, that was just a joke.  I built 2 of my 3 guitars, and both of my amps.  I always avoided pedals because I have rather big hands, and wasn't crazy about those tiny parts in those small boxes!   :icon_mrgreen: I'll get it goin' eventually.  I just didn't want these nice, helpful people to think I wasn't greatful for their help.

Johan

Quote from: Celery_Strat on January 16, 2011, 07:31:26 AM
.  I prefer to enjoy my hobbies, so when the cussing starts, it's time for a walk.  I haven't given up on pedal building at all. 

I bet when you do get the problem solved, you'll enjoy this hobby more than you'd expect..it's a great feeling of both accomplishment and pride getting a troublesome build up and running...
J
DON'T PANIC

Quackzed

yeah, no worries mate. it happens. you hit the wall. maybee we should be giving you kudos for knowing when to walk away. :)
nothing says forever like a solid block of liquid nails!!!