This kit is designed for
all Fender™ blackface and silverface amps from 1963 through 1981 with
Vibrato, with the exception of the Bronco, VibroChamp and the Princeton
/ Princeton Reverb.
First, remember that in
the majority of Fender™ amps, you must have a footswitch connection to
the vibrato footswitch RCA jack on the back panel - or at least a
shorting plug such as our FSP-200. If you are using a
footswitch, make sure that the footswitch is working properly.
A bad footswitch, bad footswitch cable, or a dirty connection to the RCA
jacks is often the cause of loss of vibrato. Note:
the Vibro Champ, Princeton and Princeton Reverb amps do not need the
footswitch for vibrato operation. These three models
are the exception; all other Fender models from the blackface and silverface era must have a footswitch connection for vibrato to operate.
Also, both the reverb and the vibrato cables must both be
connected to the proper jacks on the rear of the amplifier in order for
vibrato to function, as the vibrato footswitch receives its ground
connection from the reverb connection.
Second, it is important to have a good
12AX7 tube as the vibrato oscillator tube. If you are sure
you have a good footswitch, the next step in repairing a vibrato problem
should always be to replace the vibrato oscillator tube. The
vibrato oscillator tube is the 2nd preamp tube away from the power tubes.
If after
completing the above steps you still have missing or unstable vibrato,
the next step is to install the components in the Vibrato Rebuild Kit
inside the amplifier. Use all safety precautions in working
inside the amplifier chassis. Tube amplifiers
contain high voltage which is stored in the filter capacitors even after
the amplifier has been turned off.
Always unplug the amplifier from commercial power, and discharge all
filter capacitors before working on the amplifier circuitry. If you
are unsure about this procedure, we strongly recommend that you leave
your amplifier in the care of a professional service person.
The vibrato components
are located on the main fiber board, toward the end of the board closest
to the amps pilot light. Look for the optoisolator "bug".
See the photo at the right. You will be replacing the "bug" along
with the 3 disc capacitors next to it.
Unsolder the old
components and remove. Important: The new optoisolator is
marked with a silver dot at one end ("lamp marker") - this silver dot
goes on the end closest to the row of tubes (or, in other words, not
on the edge of the board which is closest to the control pots).
The disc capacitors are installed as shown.
There are two .01uF
capacitors, and one .02uF capacitor. The .02 capacitor goes
on the side of the board closest to the row of tubes. The
other two .01uF capacitors are installed as shown in the photo.
The two resistors are installed as shown in the photo. The
10M resistor is brown-black-blue, and the 100K resistor is
brown-black-yellow.
Use a good quality
soldering iron, good quality solder, and make sure you have solid
connections.
We recommend at
least sliding the chassis back into the cabinet before powering up and
testing for vibrato operation, to avoid the possibility of electrical
shock.
With a good vibrato
oscillator tube, a good footswitch and a solid connection of that
footswitch to the rear panel jacks, and the proper installation of the
Vibrato Rebuild Kit, about 90-95% of vibrato problems will be solved.
Strat™, Stratocaster™, Esquire™, Telecaster™, Tele™, Jazzmaster™, Jaguar™, Mustang™, P.Bass™, J.Bass™ and Fender™ are registered trademarks of Fender™ Musical Instruments. The replacement necks and bodies are for a Fender™ or Squier™ by Fender™ guitar or bass. The distinctive headstock designs and the distinctive body designs of the Stratocaster™, Telecaster™, J.Bass™, P.Bass™ and Tele™ Bass are registered trademarks of Fender™ Musical Instruments Co.
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