Marantz SA-14 acting up

It may use a belt to open and close the tray. If so that is most likely worn.
It may be the bearings the belt pulley moves on.
Or needing some grease.
Usually a tray popping back open is stuff caught in the mechanism. Might be hairs caught in there. Grease, dust a few hairs. Kaboom stuck.
If all that is wrong is the slow tray it is worth messing arounnd to discover the cause and fix it.
I bet if you open it up and watch the tray move you will find the blockage.

Thanks all. I will see if I can get the thing open and take a look.

I lubricated the slide last night which didn't seem to do anything at the time but, by morning, the tray was going back in as normal.

It's taking longer to a read a disc but still plays and, BTW, what a difference between it and the Rotel I was using as a back up. The Marantz sounds awesome in comparison!

Thanks to all that took time to comment, I appreciate it!