Marantz DV6400 vs...?

Greetings, my first post on Audiogon. Several years ago I sold the larger part of my stereo system that featured an LFD integrated, Sony XA5400ES, Spendor SA1 speakers & several other items. I did so because I needed the money, sure, but the more compelling reason was that our home simply didn't permit a layout for a quality stereo system & mine was essentially collecting dust.

Anyway, a couple years later I made some changes, set up my secondary stereo into a position where it can get plenty of play. I also invested in Harbeth P3ers, which are powered by Rotel amp & pre-amp. Question concerns my SACD player. It's a Marantz DV6400 universal player. Purchased used years ago on Ebay, I never had an owner's manual, but I do have the remote. Anyway, going through my collection I see I have a large number of SACDs. Now, when I play them in the Marantz, the light that indicates "SACD" only goes on when they're single layer (e.g. Blood, Sweat & Tears), i.e. playable only on SACD players. The majority of SACDs don't cause the light to go on, which leads me to wonder if they're being played on their pcm level.
 
In short, is this player taking advantage of SACDs?
And, if so, is that a characteristic of all universal players?

Alas, I really can't justify spending the money to replace the Sony. I knew at the time that particular sale would come back to bite me in the ass—I paid $900 for it new from J&R. Now I can't find for less than $1400. If I were to replace the Marantz right now, my budget would be more in the 500 - 800 range, more Oppo.

Naturally I'm not looking to spend a lot of money on a dead technology, but given the number & quality of SACDs I have, I think it's worthwhile to explore the best way to experience them henceforth.

Many thanks