Your unit has the Philips CDM-9 pro swing arm transport in it, the last of the best transports built by Philips. The problem is mechanical, something is preventing the laser from reaching the innermost position freely, most likely there is some dust/hair that has managed to get in there. If you aren't comfortable opening it yourself and cleaning out the debris, find a trustworthy qualified audio technician and I'm sure they can take care of that for you. It may just need a slight bit of lubrication, but be careful as the lubrication needs to be applied only to the bearing for the swing arm, and only if cleaning the debris doesn't help. The transport/laser mechanism should be perfectly fine based on the description of the symptoms. For those that don't know.. CD's are always read from the inside to the outside, totally opposite of how an LP is played, meaning the TOC is at the innermost area of the disc, followed by track 1, 2, etc... and as it plays the last song would be at the outermost area of the disc. Discs with 70 to 80 minutes of songs on them will be the most difficult for most players to play as they get to the final tracks. Older machines will have some play in the spindle motor bearing which will result in excessive cd wobble at the outer most edges, and the servo may not be able to track through that wobble resulting in skipping etc...
Anyway, IMO your problem is something that can be easily cleared up by a decent technician who has experience working with CD players, and is honest enough to not try and cheat you with some story that the transport has to be replaced. That's a fine machine and worth having serviced.
Good luck.
Philip