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|Breathing life into a dead Diaz "Tremodillo"
|Step One: Getting to the PC Board...
|A: I started out with the task of
removing the board and controls
(which were gooped down as well)
from the enclosure, being careful
not to pull to hard and cause more
damage. This one had some funky
foam glued down to the board, just
to make it a bit tougher!!
|B: Once the board and components were
removed, I began the daunting task of
removing all of the adhesive. If you try this,
make sure to take your time! I use a very
narrow needle nose pliers and take tiny
bites. If there is ANY resistance, don't pull,
just try another spot; you may be wretching a
part or wire.
|C: After an hour or so, a very nasty
looking circuit board emerges. During
the process, I was able to track down
what might be the ailment and make
note of it. It's a good practice to keep a
notepad handy during the proceedure
to write notes and draw pictures to
help reassemble the pedal.
|D: Here's the problem: the
grounded side of C5 was broken
right where it entered the
capacitor.(1) Most likely as a result
of the adhesive shrinking over
time. Also, the ground side of C2
had a cold solder joint (2) that was
probably aggrivated by the same
|E: After getting the PC board out of the
enclosure, stripping the hardened adhesive,
and making notes of the wiring layout, I
disconnected the leads and carefully cleaned
the board with a diluted solvent and
toothbrush. This is also a good opportunity to
make an actual schematic of the effect for
|F: Finally a clean, serviceable circuit
board emerges. Notice that C5 has
already been replaced. The next step
is testing the unit before reassembly
and when I replace the board it will be
shrink wrapped to prevent shorts or
damage to the circuit while making it
easier for any future servicing.
|Step Two: Diagnosis and Repair...
|I'm often found that musicians will discard a
pedal that no longer works because of the
cost of repairs. Please call me if that favorite
old stompbox finally (or suddenly) quits
working. You may be surprised at how little it
costs to revive it!
This months fun began when I received this
little fella in the mail. It's a great pedal,
worthy of the time spent under the "solder
scalpel" to get it going again. I'll keep you
posted with it's progress...
|Step Three: Putting it all back together...
|...and finally, the
|F: Well, I finally got the Tremodillo back
in shape. It turns out that there were
more problems than just some
fractured solder joints and leads. Three
of the four NTE123AP transistors were
dead, apparently from using a poor
quality power supply. (see the notch
filed out on the input side in photo G)
|G: Before replacing the back, I protected the
circuit by sealing off the board with shrink tubing.
This also makes it easier to get into for later
servicing or mods. (this photo was taken after
the mods were done) Make sure to allow
yourself enough length in the leads to route them
out one end of the shrink tube. I also do this to
many older MXR pedals that have deteriorated
foam around the board.
|"Pulse" LED Added
|9v Power port
|LED flashes with trem speed
|Not all repairs are worthy of a full article but this is a situation that I'm running into more and more. With the continuing growth of
"boutique" pedal designers/builders out there, there is also a growing number of pirates that will steal a design and put their name on it
without thinking twice about it. As a result it has sadly become nescessary to protect your work. Some engineers will simply remove
markings on the components while others will enclose the entire circuit with some type of adhesive. Often the later will eventually cause
circuits to fail making it nearly impossible to find the problem and fix it.
The Diaz Tremodillo is one of these cool 'boutique" pedals protected by a hefty armor of goop that if failing, is worthy of the time spent
repairing it. It is a "hard" tremolo based on the old Kay tremolo pedal enclosed in a cheesy but cool, blue plastic, art decco treadle
enclosure with a slider switch to engage the effect. The only control that the user had on the effect was to speed up the tremolo by
"accelerating" the pedal like a volume pedal.
Designed by the late Caesar Diaz who was famous for his incredible ability to squeeze absolutely the best tone out of vintage amps, the
Tremodillo reflects this rule for cool. With the addition of a "Depth" control and a "Speed" switch that allows the user to toggle detween
normal and double the pulse time, Diaz had taken a cheap, simple circuit and made it an interesting, useable Trem. If you an get your
hands on one of them, make sure to spend some time noodling with it. It's nothing like the "ebb-and-tide" tube tremolos found on the
early tube amps but it is a pretty cool alternative to the standard trem.
This project may not be for the fainthearted. The Tremodillo has more than a hard outer shell. It's PC board is ferociously protected by a
generous glopping of hardened goop. Hang out with me as I work to get a pulse on this tough little critter again. -"Doc"
|Caesar Diaz "Texas