Old Crybaby wah problem not working

Started by killerkev, March 19, 2008, 05:36:15 PM

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killerkev

Hello all. I came across this old Crybaby that has no output. It is one with an extremely basic circuitboard. It does pass dry signal. I tracked the signal with my trusty audio probe and have sound up to the base of the first transistor but nothing out of the collector. I measured the voltages at both trannies and they are listed below:

Two trannies #5117
Battery: 9.05V

Q1                     Q2
B- 8.67               B- 8.66
C- 9.06              C- 9.09
E-8.65                E- 8.66

All I know is that they look way out of balance. I desoldered all of the capacitors to see if this had any effect on the voltages but nothing. I even stuck another similar tranny in there but came up with the same voltages. Any suggestions?
Here a link tp the schematic:
http://www.freeinfosociety.com/electronics/schemview.php?id=350

It's pretty similar except for the transistor #'s & does not have the diode and capacitor circuit coming off the power.

killerkev


drewl

doesn't look like they are conducting, or "turned on"
without getting technical, the biggest problem with these is bad/corroded solder joints and connections, try reflowing all the components and check for open resistors.

killerkev

The board and solder joints look in good condition when I got it. Like I stated, I did desolder a few capacitors & resistors and also placed new ones in there place to no avail. I notice that the base and emitter voltages are the same so I thought it might have to do with a capacitor. Maybe I'll just change out every component and see what that does. The pedal did come without a pot which I did add one of those ICAR replica. But before I change out the components, I'll try what you suggested. Anyone else?

DiamondDog

Quote from: killerkev on March 20, 2008, 08:51:25 PM
:'( Nobody has anything to suggest? :'(

Yes- you read a sticky post, only a few up from yours. It's called DEBUGGING - What to do when it doesn't work. That will refer you also to

http://www.geofex.com/effxfaq/fixfx.htm- Fixing broken effects Q & A (the absolute must read) and then maybe
http://www.diystompboxes.com/pedals/debug.html- Simple Debugging (sorry, Aron! :) )

If you choose to read only one of these, the geofex article is your one.

One suggestion. It's been said that you should reflow the joints. You said that the joints "look in good condition". The suggestion given wasn't that you look at them- it was that you reflow them. If you're offered good, basic advice and you choose not to take it, it reduces your chances of getting more advice, doesn't it...
It's your sound. Take no prisoners. Follow no brands. Do it your way.

"Protect your ears more cautiously than your penis."
    - Steve Vai, "The 30 Hour Workout"

killerkev

Interesting reply DiamondDog.....
I stated at the end of the last post that I would take his advise and reflow all solder joints before changing out components. I have read many times the post about what to do when it doesn't work thats why I posted voltages, what the condition was, what has changed, schematic, etc...I'll take a look at the Geofex article you suggested. The observation of the solder joints was an observation that's all. I haven't had the chance to heat up the iron and go to town yet. Thanks for your reply and deep insight....

ayayay!

Wow DiamondDog, that was pretty condescending considering you've posted your own thread that was as innocent as this one some time back:  http://www.diystompboxes.com/smfforum/index.php?topic=56350.0 

Difference is, everyone else was a lot nicer than you in their replies.  Lay off the poor guy. 
The people who work for a living are now outnumbered by those who vote for a living.