PDP 11 - how to lock heads in a rx01 and rx02 - seeking advice

tony duell ard at p850ug1.demon.co.uk
Fri Jul 10 14:22:37 CDT 2015

>     > From: tony duell
>     > I find [RL0x's] easier than RK05s

> Try taking out an RA81!

I did an R80 (not much lighter) single-handedly.

The trick with those is to take the HDA out. It takes only a few minutes. Raise
the logic chassis (top part of the case including the front panel), then lock the
heads (you MUST do this anyway), release the belt tension (lever at the front
right), then unplug 3 cables (2 small ones on the front of the HDA and a 40 way
ribbon from the PCB on top), take off the 4 mouting nuts and lift the HDA up and
out. Then tape the spindle pulley so it doesn't turn when moving the unit. If it turns
backwards it is likely to damage the heads.

The rest of the drive (chassis, PSU, motor, logic PCBs) is just about liftable fully 

I think the worst is the RA60. It's very heavy and it is a pain to dismantle. You have to take it 
apart a little bit at a time.


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