Chorus/Vibrato problems

["james.eaton" <james.eaton@ac.com>]

When I got my A-100 out of storage, the chorus was chopping the sound instead 
of modulating it.  After I shorted one of the capacitors on the delay line to 
earth, the sound returned to normal again.  The next time I played a lot of 
notes, the chopping sound came back.  I shorted the same capacitor out again 
and the sound has been okay ever since.

Can anyone explain in technical terms what is going on ?

I am guessing that I probably need to replace the offending capacitor at some 
stage.  If so, does it need to be any particular type such as mylar, metal film 
etc ?

James.Eaton @ ac.com