Are you sure it is a DR 2 or 3 and not a DR 5.x ? A flash from 1.36 and up will work on a 616 DS at DR 5.x ok. Text in 616 cabinet should be grey or green. Green denotes DS cabinet. Also check cartridge for DR level and DS function. Only pull cartridge powered down, but move fast, as memory capacitor could be tired and you could lose programming. The old Mini units had a hard drive that would be quite reliable until that one day it would not spin and then it bricks.
I will need to double check, but I kind of think that you have a higher than DR 3 unit as I did not think DR 3 on the 616 would support any voicemails-- 824 might have, but I do not recall 616 doing so at that level.
The last time I had a Mini die about 3 years ago on a 616 DR 5.1 DS, I was able to replace with a Flash 1.7 with no problems (have to do the reinstall process).