used edp - strange humming

[mjnoble <not8ohm@iinet.net.au>]

Hi folks,

An aquaitance of mine happened to have a an edp just sitting around 
which was rescued from a tech disposal at the music store he works at 
(yes, it was going to be thrown out!).  Thing is, he is prepared to sell 
it to me at a potentially unbeatable price. 

Are there any caveats to look for when buying a used edp.  Its maxed out 
in memory already,  has no footpedal, but appears to be working 
perfectly except for a loud electromechanical sounding humming coming 
from the lid near the power supply.  It only hums when the lid is on the 
unit however - without the lid it seems like a perfectly operational 
edp.  Anybody out there have any ideas what this humming might be?  Do 
all edps hum like this?  I wouldn't want to buy the unit and have it die 
on me straight away, as getting it fixed here in Australia might not be 
the easiest thing.

thanks in advance for any replies,

Michael Noble