As far as I know the Krell KPS 20I used a Philips CDM9 Pro transport. Those were quite robust actually. I assume you’ve done the simple stuff like cleaning the laser lens.
A company called Enco Systems bought out the remaining supply of new factory stock CD Pros when Philips discontinued it. A couple years back Enco was asking $500 for a new one, now it’s $999, but yes, new units are available. I think Krell made a custom spindle so it may not be a drop-in replacement, however.
That Krell player was a beautiful piece of kit that deserves to be restored. Good luck! And if you decide to get rid of it anyway, I’ll take it off your hands 🙂