Broken pedal repair options
Zootal
equipment to replace the little flat ic's that are in this thing, so my next
option is to find someone that can. The local shop wants a minimum of $50 to
check it out. I can ship it to DigiTech, but shipping plus their minimum fee
is about $50.
Any suggestions? What other options are there to get something like this
fixed? To be honest, this pedal isn't worth $50 to me - I can get another
one that works for less then $50.
Jim
I think you already have the answer, if a working used one is less than
repair.
You might try to sell it broken, but if it has surface mounted stuff, it
may be land fill. Or a fancy doorstop.
Zootal
"Jim" <j...@askmebeforeyousend.com> wrote in message
news:kcydnURq8OqwIAjX...@posted.isomediainc...
I'm afraid you are right. I might have a go at fixing it...at this point I
really have nothing to loose :(.
Maybe I'll replace the guts with a board of my own design. That might be
easier...and come to think of it is starting to sound like a pretty good
idea...hmm...
ian field
"Zootal" <use...@spam.zootal.nospam.com> wrote in message
news:0eydnU5jrY8IXgjX...@giganews.com...
If it was made with lead free solder that might be the first and most
obvious thing to check.
Lead free solder usually looks like cold joints and often performs
accordingly!
Zootal
"ian field" <gangprob...@ntlworld.com> wrote in message
news:Ctwlm.3745$f92....@newsfe30.ams2...
I went through it last night. Found out that something on the board appeared
to be latching on power up. The power goes through a pair of 100 ohm
resistors in parallel, and the voltage on the board side was 3-4v. After a
while it would rise to 7 or 8v, and then it would power on (ie the led would
toggle when pressing the pedal button), but it still didn't pass audio
through. All of the op-amps are biased properly, input and output floating
about 1/2 supply voltage. At this point I give up because I don't have a
schematic and it's just not worth the time it would take to trace the
circuitry. It's all surface mount micro circuitry - transistors 2mm in size,
diodes and other components the same size. That's progress for you...
ian field
Just a stab in the dark - any electrolytics, and any of them getting warm?
Zootal
Several - checked them last night. What is funny is when I power up the
board, something draws enough current to load the supply down to 2-3 volts,
but if I bypass the 100 ohm resistors (the ones in series with the power to
the board) with just another 100 ohm resistor for a second and then remove
it, whatever is doing it stops, and the voltage jumps right up to 8v or so.
It stays there until I power cycle the board. My first guess is that one of
the op-amps is latching or otherwise defective, as I'm pretty sure a bad
electrolytic wouldn't do that. For that matter, neither would a transistor,
diode, or any other discrete component. The board has 3 dual op-amps, the
switching ic which seems to work (but could be what is latching on power
up), and a ton of miniature trannys, diodes and other discreet components.
Unfortunately, after it powers up, it passes a clean signal, but the dirty
signal is greatly attenuated - meaning something is blocking it, like a bad
cap or tranny. This is where I get lost due to the lack of a schematic and
the bazillion surface mount components on the board making it hell to try to
trace the signal path.
ian field
Leave the extra 100 Ohm resistor in permanently and see if it fails
properly - at least a fault that stays put is easier to trace.
Zootal
Oh, I did. I soldered it in place last night - and that was no mean task
considering the size of the components and the 40w iron I was using LOL. Now
it powers up just fine. It uses about 28mA, which I guess isn't too bad.
Voltage to the board is about 8v, but still no dirty signal gets passed. I
can even identify the approximate area of the board where it gets blocked,
but that is a bit of guesswork.
Zootal
I'm tempted to bypass the resistors completely and see if something
smokes...I don't have much to loose at this point :)
ian field
If it runs on a PP3 battery there won't be enough current to force the magic
smoke out of much.
Get a jewellers loupe and catalogue all the SMD resistors first, if you use
a powerful enough wall wart any resistor that takes the knock from something
going short might burn up its lacquer coating along with the value marking.