Disc will not play appears to be skipping

its cd lens weak or defective solution replace lens

The Optical Pickup(laser) may be weak. It takes much more power to record than play, which I guess it works.

You should realize that this player is about 20 years old.
It was not designed to read CD-R or CD-RW media.
The signal from these media types is different from audio CDs you buy.

Not all CD players can or will play CD's burned in a PC. Sometimes the CD player is to old, so not compatible with these CDs. Sometimes the player just does not play these CD's, because of rights protection.
A CD burned in a PC is less reflective than an normal music CD. Normal CD's do have a metal coating and are highly reflective. Burned CD's have a dye, and where the laser burned the dye, it only changed colour. Making it less reflective.
All modern CD playes should be capable of playing CD r's. But the player that is really compatible, is labelled CDr and CDrw compatible.

Have you pressed skip disk for tray 8?

Hello
If a disc has been put in the slot of the disc in play, Remove the disc, whose number is displayed, and press stop button.
Because of light or noise, the changer has detected a disc in the lot of the disc being played, even though it is empty. Check whether there is a disc in the displayed slot. With front panel closed, hold down "STOP " button for atl least four seconds or more.

Read this and decide if you or a pro should look at it...

http://www.repairfaq.org/sam/cdfaq.htm

I contacted a friend who operates a sterio shop and was convinced that fifteen years of bouncing up and down has made the laser unable to focus and read the info on the disks and the solution is to buy another one . Thanks for you're interest.

change the motor disc spindle

You have to removo all disc
Then turn on the unit and let do the initialization process