aa270 twin reverb, no vibrato

[JMadson]

I recently aquired a aa270 twin reverb that needed some repair, I've got it running, but no vibrato, also, the reverb is on both the normal and vibrato channels. This sounds like a mod I heard of years ago where some people thought that the very existance of the vibrato curcuit sapped tone, and while your at it, make the reverb work for that normal channel, too! anyway, I'd like to make the amp back to stock, so any advice would be most appreciated...
Jason

[Don Symes]

Working from the AA270 schematic at the Fender Field Guide, fist, check to see if the vibe's intensity pot is even connected to that node just before the PI.

Then, see if the roach is flashing - no flashy, no vibe.
To see if it's the roach or the oscillator, with the vibe on a LOW speed and a meter watching the first oscillator triode's plate, see if the oscillator runs at a speed controlled by the speed knob.

Good luck!

[Sweetfinger]

I just fixed one...

The CdS cell in the roach was open, so no vibe. I had to do a quickie turnaround so I replaced it with the replacement cell for a Morley wah. Worked great!

[JMadson]

got it!

yep, cell was bad, and also had an open cap in the curcuit...
thanks...
J