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RL drive cleaning

Q

Qbus

Veteran Member
Joined
Feb 23, 2011
Messages
963
Location
Salisbury Maryland
Think I mentioned that the signal RL-01 drive that I had on my 11/23 went flakey, now that I have a 11/34 dual RL-01 drive system the fun around the house has been building bootable system disks for each system and putting the original RT-11 system disk on the shelf for safe storage but about this time the drive on the 23 died. Turns out that I had to replace the head assembly on the drive, I had a parts drive that provided another head assembly and have performed the head alignment enough times that this was not an issue. Think that there is not much that I have not had apart or repaired on a RL drive so getting to know them well. The question is what to do about head cleaning? I have been using denatured alcohol and paper towels where I spry the alcohol on the paper and then lightly pass this in the direction that the head travels across the disk. But looking at the head assembly that I removed can see a buildup of oxide on one of the head pads and am wondering if the head pads were covered with a lubricant that when you clean the heads this way it damages them? Will go back and look at the manual and see if they have anything about cleaning the head pads but don’t recall seeing anything, only the stuff about replacing the entire head assembly if it does not have proper output. If anyone has ideas or comments on the care and cleaning of the head assemblies let me know. Using alcohol and cleaning in the direction of tape travel is an old audio and video head cleaning process but perhaps it’s not good for large platter hard drives?
 
Additional information:
Ok, so it’s a slow day at work so I just reviewed the “RL11/01 Disk and Sub-System Training Handout” the “RL01/2 Users Guide” and the ever popular “RL01 Field maintenance Guide” and the only thing I found was paragraph 3.4 to 3.5 on operator maintenance about cleaning the unit, cartridges and spindles and it tells you to use a solution of 9% water and 91% isopropyl alcohol but don’t use too much. Still don’t see anything about cleaning the heads. Did see in the description of the heads that they are ceramic and don’t let them get scratched or rub together.
 
If my memory serves, we were always cautioned against using isopropyl alchohol to clean disk heads, and should use denatured alcohol instead. We were often told that isopropyl can leave a residue that could interfere with the aerodynamics of the head flying. I worked mostly on CDC SMD drives, and I think we had CDC issued cleaning solvent and swabs rather than off-the-shelf cleaners.

I dunno if this is at all applicable to RL drives.
 
Gents,

Good or bad, I use 91% alcohol from the drugstore and q-tips to clean heads on RL drives. I have cleaned all my drives and other's drives that way. I move the swab back and forth from one's left to right (and back) if they are standing in front of the drive. This has always worked fine. Watch the tip of the swab often and toss it when debris starts to come off. This could take a number of swabs as I have had to really work appreciable amounts of junk off some heads. Also be aware that the heads are suspended on little stainless frames that are held to the arms with two fine spot welds. It is easy to bend the frame so do not apply too much pressure to the swab.

Lou
 
I oil all the ball bearings that I can see when ever I see them, the one on top the drive motor is easy to get at with the one on the bottom being a bit more work. Have had the spindle assembly out before and the bottom bearing is fairly easy to get at but don’t remember about the top bearing. Spindle is an easy removal though. I tend to soak the ball bearings with 3 in one oil and then dry them with paper towels to keep the oil from getting on other things. Big long term question in my mind is what to do when the belts fail? Synthetic drive belts are not that common any more. Can not imagine what it would take to try to keep one of these old drives running continually in commercial service.
 
The RL family drive has a belt between the head drive motor and the center spindle. Maybe because the huge size of the RL disk pack or that’s just how they did things back then there is a AC motor with triac speed control that drives the main fan and hub spindle via a drive belt. Servo control, tach system and drive train are more closely related to a video tape recorder then anything used in computers. The RX-01 and 02 floppy drives also use an AC synchronous motor and drive belt to a central spindle but other then incoming AC line frequency have no speed control. Also the RX drives have the annoying habit of running all the time the system is powered on. I wasted way too many hours learning and working on these things, but when they work it can be a thing of beauty to see and unlike modern drives you can get in and work on them.
 
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