Emax

Hi. 
Here's a strange problem...
I've got an emax II HD with a zip 100 connected to the scsi port. It 
has been working brilliantly for the past months. 
But know it has been acting wierd for two days. The problem is 
that it suddenly stops giving any output at all and becomes 
completely silent. I can load a bank, then play it for a couple of 
minutes, then all of a sudden it becomes completely silent. It 
doesn't matter if I load another bank, it's still completely 
soundless until I reboot the emax (i.e. turn the power off and then 
on again.)
I would reallt need a solution to this problem, since were in the 
studio and really really need the sounds from the emax...