Sounds as if the laser is failing. Failing to read SACDs is the first sign. It doesn’t get better as time goes by. Listen to it while you’re shopping for a new unit. Sorry to be the bearer of bad news but you aren’t the first one to experience it.
Marantz SA-11S1 SACD player not reading hybrid SACDs
I have had one of these units for several years. It loads regular CDs fine, but will read only about 50% of the hybrid SACDs I have tried to load into it. It will try to load for about 30 seconds, then the display says "can't read". It seems to especially dislike trying to read RR and BIS hybrid SACDs for some reason. Has anyone else encountered this problem with this unit or guess what the problem might be? What is interesting is that I recently acquired a Marantz DV-9600 DVD/SACD player. It appears to have a similar loading mechanism as the 11S1. So far it has loaded every disc that the 11S1 has failed to do, and sonically I find it similar to the 11S1.