Sony CD player CDP XA 20 ES question

I have a Sony CD player model CDP XA 20 ES which I got as part of a bulk audio equipment purchase. I definitely like the looks of this, but it has issues - everything lights up and appears to be working, except when the tray is closed with a CD in it, nothing happens, as though the unit doesn't "see" the disc in it. Anyone have any ideas, and/or is this worth getting repaired? Thank you.
This unit was the next model down from the highly praised
Sony XA7ES. Parts for both these units are iffy at best due to age. Problem could be a lazer and sometimes parts are on Ebay. Worth fixing if possible..Good luck.
Thanks for your responses. I've since found out that this player is supposed to have a "stabilizer" which as best as I can tell looks like a 3/8" thick 45 rpm record adapter, that you sit on the disc over the center spindle before closing the drawer. If this is amongst the load of stuff I got, I'm not able to readily find it. Anyone know if this player would work without the stabilizer? Thanks!
Please make sure you are using the supplied cd center weight, if not the unit will not respond.
Thank you, I think I need to find this stabilizer before I take the unit in for "repairs"!