View Full Version : RL0xK-DC Disk Cartridge Maintenance

March 18th, 2011, 04:06 PM
I'm looking for information on maintenance procedures, supplies and apparatus for RL01K-DC and RL02K-DC disk media.


Back in the day, about once a year, we used to contract with DEC to have a service tech come to our engineering facility and do preventive maintenance on our entire inventory of RL01 and RL02 disks.

This included, cleaning [with a soap solution], decontamination, inspection and replacement of worn or broken cartidge parts, in essence refurbishing our entire collection of RL media.

This was timed with PMs on the drives themselves, in order to prevent cross-contamination issues, and prolong the life of both drives and media.
Documentation of procedures and tooling needed for drive maintenance is readily available. I would like to know where to look for / find documentation of any kind relating to the media maintenance I've described.

It is quite possible that I have these materials in my possession already, and not realize it, since I have a DEC MDS QBUS microfiche set. If someone knows it's in that set, I can take it to a reader to obtain what I want, but right now I don't have the ability to access the set without a road trip.

As I recall, the device to perform this "cleaning" was a rolling cart, about 20"x30" and 40" high. It included a bath, light, inspection mirror... etc. Last time I recall seeing it performed was in 1984?

Anyway, your recollections or contributions will be appreciated.

I am preparing to access my RL media after 22 years on the shelf, and I think it's a wise precaution to PM them before taking the chance of loading them in a working drive.

March 19th, 2011, 02:22 AM
Hello, I can recommend the site from Joerg, http://www.j-hoppe.de/PDP-11/My_PDP-11_44/RL02_disk_trouble/rl02_disk_trouble.html

March 19th, 2011, 08:42 AM
I see lots on drive and controller repairs, nothing on cartridge maintenance.

Interesting fellow though.

March 23rd, 2011, 01:10 AM
My recollections of the RL0x Cartridge cleaning sessions and device is becoming clearer.

The company we most often called to PM the RLs was "SCOPUS (http://www.corporationwiki.com/Massachusetts/Lowell/scopus-corp/29566601.aspx)". The service they offered was called "DATA SAVER".

This company name has been re-purposed in our current world, as well as the phone number. I find only this reference (http://www.rsts.org/rstsproaris/Aris01.log) to them on the Web. [That link is to an ancient forum thread - search for "SCOPUS" and you'll go right to the relevant posts]

As I now recall, DEC had some surprises in the product lifetime of these disks, and not all good ones. After a time in the marketplace, one of the major concerns to surface was of over stressing the disks within the cartridge. This was too easily caused by accidentally dropping them.

This resulted in a microscopically bent platter, which could crash heads if loaded.

To fight this, DEC instituted the "ShockWatch (http://www.shockwatch.com/)" program. This was a "stick on" G force indicator. It was placed on all cartridges and provided a visible witness if it had been subjected to potentially damaging stress. [or NOT]


The most important inspection done during a PM was to physically verify that the platter within the cartridge was still "flat" enough not to cause problems, in addition to looking for contamination of the surface and evidence of head crashes.

To accomplish this, the "Cart" I referred to previously, was actually built from the lower half of an RL drive, including a spindle. This had been somewhat modified to allow physical access to the area where the heads once were, and included a mirror, light and gauges to check the platter in rotation.

To begin the PM, the cartridge was installed in the machine, in exactly the same manner as it would be inserted into an operational drive. This released all the movement interlocks built into the cartdridge case, centered and engaged the platter on the spindle, and freed the assembly for rotation.

Then, using the tools provided, the tech inspected, measured, cleaned and re-stickered the cartridge. The ShockWatch was added if missing, or replaced if triggered or damaged.

Fatally rejected cartridges were usually disassembled with the customer watching to show the value of the service, and prevent the disk's accidental re-use.

We all had souvenir disks hanging on our cubicle / office walls. Some were made into clocks or used as Frisbees and in one instance became a target at the rifle range.
I wonder where mine went?

March 30th, 2011, 07:06 PM
As promised, here's an image of an RL01 as prepped by SCOPUS and last cleaned, inspected and re-certified on 3/1987.

Note the "Shockwatch" installed in a location where it will not be easily knocked off, or damaged by anything other than it's intended purpose.