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

tony duell ard at p850ug1.demon.co.uk
Sun Jul 12 08:21:19 CDT 2015

> Thank you all for the excellent information. I think i have a pretty clear
> idea on what im dealing with now. Quick question though, what if there is a
> pack in the drive?  What holds the pack in there? Can the pack be removed
> without power?

Believe-it-or-not the pack is held to the spindle by a magnet ring. Yes, a magnet, that close the the

You can't open the drive in the normal way without power. I DO NOT recomend powering anything
up though. There are 2 ways round this, depending on the age of the drive.

On early drives (certainly RL01s, I am not sure if any RL02s were made this way) there is a little cover
on the right hand side of the drive (on the side panel), held on by 2 screws. Take if off. Behind it you will
see the door lock solenoid. With a flat screwrdriver, pull the armature down, and hold it down while 
sliding the catch on the top. You can now open the lid to remove any pack and move the head
lock bracket.

On all drives you can get inside by first extending the drive all the way out on the slides. That is, pull
it out, then fiddle with the little rocking levers on top of the slides until it will come out some more.
Now, the drive top is in 2 parts. The front part is the door over the pack. The rear part is the cover
over the electronics and is retained by 4 captive screws. Undo these. Then lift the rear edge of the rear 
part of the cover -- carefully -- until you can unhook the front edge from under the rear edge of the 
door. Now swing the rear part of the cover rearwards -- lifting the front edge. There is a PCB fitted to the
inside of this cover with lots of cables going to it. Don't panic, there is a little bracket on the PCB//cover which
lets you hang it on the back edge of the main drive chassis. You don't need to unplug anything. Now lift the rear
edge of the door part of the cover slightly until you can slide the catch on top of this cover. When you do that
the door will come free. Lift it off. There are 2 spring-loaded arms at the back of the door that will snap over, 
don't worry.

Now you can see if there is a pack in the drive. If there is, lift out the white cover (looks like a large, shallow, 
bowl, open side down) and turn it over. You then see the top of the pack. In the middle is a handle, brown
for an RL01 pack, blue for an RL02 pack. On the handle is a little square slider. Slide that over and while 
holding it in that position, raise the handle. It will be stiff (if it isn't, you've not moved the slider properly).
Lift the pack out by the handle and put it into the cover you just removed. Lower the handle and the pack
will (magnetically) lock into the cover. You can now raise the handle again  without moving the slider and 
carry the pack by the handle.

To put the covers back on, put the door in place almost vertically, and position the spring-loaded arms on
their guides. Now unhook the rear cover from where you hung it on the back of the drive and fit it under the 
edge of the door. It will hold the door pivots in place. Tighten the 4 captive screws. Lower the door
and clip it down so that it locks.


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