Hi,
I have a spare DSL-720A DVD ROM that I bought (I bought 2 some years ago) as a spare backup for my 800 Reference.
I have since sold my 800 Reference player with one of the two spare DVD ROMs.
These are difficult to find & can be a "life saver" if your 800 Reference has a DVD ROM that is playing up or failed.
Once the outer casing is removed it's pretty straightforward to swap over - housing screws, Molex plug and multi-pin connection plug and that's it (similar connection to DVD ROM in PC).
I never tested the replacements out, so sold as untested.
PM me with an offer if interested & want to take a punt as I no longer have any Meridian machines that incorporate this ROM.
Regards,
Step