The RL02 disk drive and the RL11 (M7762) controller

How I got my unit..

I "met" Ed Groenenberg on vcfed.org where he wrote something on a tape unit that I was interested in. We started talking which ended with me visiting him. Ed has a very nice collection of ancient computing related material: a lot of teletypes, a PDP11/70 and a lot of other peripherals. And he had several RL02 drives - and gave me one! That was unexpected and I'm really happy with it, thanks Ed!

After a while I also got the RL11 (M7762) controller and cables that go with it, so now it's time to go and play with it..

Pictures

The RL02 drive is an impressive beast:

The RL02 with a disk cartridge sitting on top of it. The second button on the front is the drive number, here a 2.

It opens at the top to insert the cartridges:

The lid opens at the top to take the cartridge, exposing the spindle and the head area below it.

The heads were protected during the trip by this little plate:

The plate that held the heads in place during the trip.

Opening the back panel exposes the motor and the power supply:

Behind the back panel: the power supply board at the top, the drive motor below it.

And the back panel itself holds the controller PCB:

The back panel itself carries the drive's own controller board.

The Drive number button

You can have max. 4 RL02 drives connected to a controller. Each drive has a drive number to identify it, from 0 to 3. The way the drive number is selected is quite special! The second "button" on the drive shows the drive number. This button can be removed! By simply replacing the button with a button that shows a different number you change the drive number. This works because the button holder has a number of microswitches that "sense" the cams at the end of the button. I only had a drive button 2, and many tools require a drive 0. Luckily someone created a 3D model for those drive buttons! Thanks a lot Vince Slyngstad!

A copy of these files can be found here: 0, 1, 2, 3.

Drive measurements

To make sure we have a properly working drive we need to do some measurements and alignment checks....

Getting it to work (controller 1)

The controller for this device is the RL11 (M7762). I have two of them, this is the first one:

The first M7762 RL11 controller, with the usual green engineering-change wiring across the component side.

The controller was defective so it needed repairs.

This controller - and the drive - seem to work properly at this point.

Controller 1 - bad again

But a few months later the controller (or the drive) has a problem again...

ZRLG Seek difference failure

Controller number 2

The second controller had a "defective module" label:

The second M7762, still carrying its 2008 Defective Module tag. The fault description says it died in use and suspects the electrolytics.

This also needed repairs, which was quite interesting.