.....has become very picky. He owns a Mark.I Cambridge Audio Transport which, up until recently, was working fine. However, if the unit is left switched off for a while it won't play any discs until it has 'warmed up' for 30 minutes or so. I thought it may be moisture on the laser but his house isn't particularly susceptable to excess humidity. Could it be a mechanism or circuit problem ? (Yes, I know he could just leave it switched on :p )