Hey!
I don't live in your area. Similar problem happened to my Sony CDR-W33 CD recorder 2 years ago, the machine was made in 2000.
I opened it up and look around. Like you I thought it was a dirty lens at first, but it wasn't. After watching the tray opening and closing for awhile, it turned out to be a single small rubber drive belt that close and eject the CD tray, but it also function as a pulley to lift whole laser housing up and clamp up the CD once the tray after is fully closed back in.
After 19 years the belt stretched and slip. So, it only have enough tension to open and pull the tray back in but not enough tension to pull the lifting laser/motor mechanism housing up. Luckily, I found a replacement belt on eBay for $7 shipped and problem solved. Crazy that a little belt can kill the whole machine.
Anyway, depending on your transport in your CDP, it could be a whole different problems. Good luck.
Buddy