Are you sure this ic is defective?, they rarely break down.
The original AQ version is no longer available, but is replaced by the cxd2500BQ (onkyo part no.:22240487A)
Available in holland by ASWO or ASWO based webshops.
This ic is also used in a lot of different brands and players, I just don't know the exact types.
The really big problem with this player is the laserunit (SPU3011 or SPU3013), this is usually the cause of all kinds of problems.
But it's not available anymore! (it wasn't 10 years ago, and won't be now)
(your name sounds familiar, are you also active on circuitsonline.net?)