Put in clean commercial disc and get error msg "no disc" period!

Does the laser move and try to focus once the disk in loaded?

try manualowl.com

http://www.manualowl.com/m/Sony/CDP-CE500/Manual/191615

The laser eimission might have stopped. The laser pickup unit [optical pickup unit] should be replaced.

Try changing the (only) belt the player has with a brand new one. Go to www.partstore.com. I believe it costs more than $10. Clean the pulleys with isoprophyll alcohol using a cotton swab after removing the old belt.
After you remove the top cover, take a careful look how the belt is placed. Don't unscrew anything. The belt can be removed and replaced without removing any screw. A paper clip will help if you don't have the right belt removal & replacement tool. A commercial CD lens cleaner (I use Scotch brand) will greatly help. Just insert it in your magazine and run for a few seconds to a minute. This is not a sure fire solution but most of the problems in this model is attributed to an loose/overstretched old belt and a dirty laser lens. I hope this helps & good luck!

You don't KNOW it's dirty.

Before you dive in and possibly wreck it, read this...

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

http://esupport.sony.com/US/perl/model-find.pl?mdl=CDP-CX151&PRODTYPE=33,32,63,71,7,102,26,80,72,44,55,27,74,84,57,61,103,89,10,35,78,48,77,29,50,39,64,58,12,41,81,52,60,73,66,101,45,76,86,62,54,67,70,68,17,2,1,88,100,82,25,28,83,59,69,49,24,104,53,79,42,22,46,13,6,85,36,3,51,9,47,38,4,34,37,43,5

It is clear symptoms of bad optical laser or dirty optical lens.
Please put lens cleaning CD in player, play that CD to clean dust on optical lens surface. If that helps, fine or replace optical laser block in player.
I can provide you optical lens part number, please confirm is it Sony CDP-CX153 cd player or any other model.
Thanks.

Try using a comerically recorded disc.Or you can purchase a Cd lens cleaner disc and clean the laser

Please replace optical block (laser) of CDP-C235.
It is available in Part Store.