Is it the cd?
I played a cdr this weekend and it sounded just like a record with a
scratch. Turned out there was a fault in the recording. Try a different
disc.
I had an Alpha 7 from an auction with a smashed up front panel. I wrote
to Alpha and they were happy enough to send a replacement. Made it good
as new. Great cd player, flimsy build but a weighty sound.
If its the laser its usually mistracking that is the symptom.
May be your pcb somewhere.