DL4 problems

["Steve Lawson" <steve@steve-lawson.co.uk>]

My DL4 has started making some rather strange noises - sounds like someone 
blowing into a microphone intermittently - lots of
hiss and a shifting other noise... not nice at all, and likely to ruin 
gigs should I use it (had a solo gig Saturday and
fortunately it wasn't doing it, or at least not too loud anyway...

Any suggestions as to what it is and how to fix it?

cheers

Steve
www.steve-lawson.co.uk