You didn't specify the problem.
With the SA-11S1 it is usually the laser going bad and not reading TOC on sacd's. If that is so, the laser is the HOP1200. It is still in production, cheap, and easy to replace. There is no adjustment to do, just swap the laser mechanisms.
That said, these lasers tend to have a short life. Your player is old, like really old. So either you didn't play it much, or you have been lucky. Any technician who works on cd players can install a new laser in these players for the minimum shop charge as it doesn't take too long to do.
If you have a different problem, then that is something altogether different. As the above post mentions, critical parts for this older player are generally not available any more unless the needed part can be salvaged from another player.