Emu XL-7 & MP-7 User's Group

I just got another MP-7 (i returned the last one) and there is this awful noise 
coming from every output. it's not typical analog humming or buzzing but 
rather a nasty digital scrape that happens like every 2 seconds. it has the very 
first OS in it. is this a known problem with OS 1.0? i can't see how an OS 
upgrade would fix a problem that sounds like a short on the processor. i think 
i'll just return it and get my money back. anyone heard of this before? it's a 
shame there is no archive here to look things up.