11 Nov
2013
11 Nov
'13
3:33 p.m.
The HDA is the sealed assembly with the platters and heads and was
sometimes (often?) replaced separately from the rest of the drive. The
IIRC the rack mounting procedure for these drives tells you to take the
HDA out if you don't have a suitable jack to support the entire unit, so
as to reduce the weight. Removing the HDA is very easy, just a few ribbon
cables to unplug, then de-tension the drive belt with the lever on the
side of the chassis and take off 4 nuts. The HDA then lifts right out.
HDA is installed in a chassis that forms the rest of
the drive and mounts
in a standard rack. The drive motor, the logic boards, front panel switches,
power supply, etc. are inside of the chassis, outside of the HDA.
I wonder if the OP was thinking of the RM80, which, IIRC, was the R80
drive (the not-quite-SMD drive used on the 11/730) with an external
Massbus interface unit in the stand.
-tony