I have a problem with my Densen CD420 CD player (about 3 years old). Many CD's seem to jump and/or stick and then a loud electrical noise comes out through the speakers. It seems to happen around the middle/latter half of the SD. I've tested the CD's on a Bose Wave in a nother rrom and it doesn't happen. Any suggestions? The dealer is no longer trading and I bought the Densen half-price in the sale.