On Fri, May 31, 2019 at 11:17 PM Jon Elson via cctalk <cctalk@classiccmp.org> wrote:
> As far as I remember, there IS no removable > cover on those HDAs, they were hermetically sealed except > for a tiny, filtered, pressure relief vent. Well, the HDA was assembled, so it can come apart again. The RA82 printset gives rather more details of the HDA than the others, (different HDA of course but the same idea). But I think that opening it up outside a cleanroom will do a lot more harm than good. > I think the procedure to update those HDAs was a pretty > involved disassembly. Actually, getting the whole HDA out of the drive is quite easy. It's even in the user manual, as it is sugested that you remove the HDA to reduce the weight of the drive if you want to rack-mount it. Basically : Raise the logic chassis on the gas struts Lock the heads with the lever on top of the HDA. The drive should really be running for this to avoid scraping the heads across the disks. Then power down (obviously!) Lift the drive belt off the HDA pulley using the lever on the right hand side of the drive chassis. Unplug the cables: Two small ones on the front of the HDA (servo head output and positioner drive) and the largest one (rear edge) of the read.write PCB on top of the HDA. You can remove the read.write board now, or take the HDA out with it attached. To remove it, unplug the other 2 cables and take out the 4 fixing screws Remove the 4 fixing nuts/washers for the HDA Lift it up and out. You can stand it on the 'feet' moulded into the front cover of the HDA. -tony > > > Jon
