While I am not familiar with the Universal player specifically,
I am always suspicious when about half of any mechanism stops
working suddenly.

My guess would be that the system is divided into two separate
sections, and one of the two (stacks) is not getting any vacuum
for some reason.  Perhaps there is a foreign object (like a mouse?)
caught in the tubing to half of the stack, or a hose is ruptured.

No matter what, sudden failures to half of a mechanical device are
probably caused by something simple that should be relatively simple
to track down.

Jack Breen
Southboro, MA

 [ What if the black keys work and the white keys don't?
 [ Answer: mal-adjusted keybed locking device.  ;-)  -- Robbie