Twin Reverb--Clicking Vibrato

[chrispucher]

Hey all,
So I bought a blackfaced 1970 twin reverb today. phenomenal amp! however when the vibrato is turned on, there is a pulsating clicking noise that increases when you turn up the intensity and speed. it's pretty faint when you're playing but its enough to annoy me. i've heard this happens to a lot of fender amps. is this a cheap easy fix? or is this going to cost me an arm and a leg?

[WaltC]

this may be a common problem that happens in this amp :
"
The official Fender solution (Service Bulletin number 9)
"The ticking caused by the Vibrato is caused by improper lead dress.

It can almost be "cured" by connecting a .01 mfd 600 volt mylar capacitor
on the 10 meg ohm resistor in the vibrato circuit. this resistor is located
on the parts panel. Remove capacitor across the 10 meg ohm resistor (old
modification) if in place."

(That is, run the cap from the junction of the 10 meg resistor and the
optoisolator to ground.)

"If this does not produce the desired results, then the leads should be
dressed as follows and excessive lengths shortened.

1. Dress the leads to the vibrato speed and intensity controls away from
the tone controls and filter leads.

2. "Bunch" the leads to the components on the parts panel which connect to
the tube socket of the 7025 (12AX7) vibrato tube."

or to put it another way:
"
The Fender tech-note solution is to connect a .01 cap at 600v from the
left rear leg of the optocoupler (the thing thal looks like a large bug with 4 legs)
to the left front leg of it. This is looking at it from the rear of the chassis.
"