Is it possible to run a PS6510E half populated?  I know some EQL models support this configuration but I was having a hard time finding definitive documentation regarding the PS6510. 

Currently it is fully populated with 48-drives, but some are failing, and we'd like to rebuild it half populated and save some of the remaining drives for another unit.

And yes, both units are out of support (and cannot be renewed anymore- past 7 years old).