RL drive lubrication

Tony Duell ard at p850ug1.demon.co.uk
Tue Apr 11 13:51:13 CDT 2006


> pretty good condition, cleanliness wise.  I replaced all four course 
> filters, and
> checked the absolute filters, which were actually okay even in the dirty 
> drives.

The RL airflow is rather nice in there's air circulated round the disk 
pack, the absolute filter and the outside of the 'heat exchanger' tubes, 
and a second airflow through the prefilter, the inside the of the tubes, 
and out over the heatsinks and the PSU fan. While the first system is not 
sealed, there is less interchange between it and the 'very dirty' air 
than in most drives, so the absolute filters last longer.


>  
> Because all of these have been powered off for many years, I opened them 
> up and
> pulled the power supply for a session with my capacitor reformation rig 
> after
> cleanup.  With that successfully accomplished, and finding that all 
> voltages were in
> line, everything was reassembled.  During the wait for the capacitors, I 
> cleaned the
> interior pretty well with a vacuum and Windex.  As a side note, three of 
> the drives
> still had the platter brushes installed, and since I already had each 
> drive opened
> for power supply checkout, I went ahead and removed the brush assemblies.

What did you remoce? Just the brush tips? Did you leave the motor, the 
microswitch, and the operating cam? Without those, you might have 
problems getting the drive to go ready.

>  
> Fortunately, the 'clean' set of drives are now fully functional, having 
> been tested
> with one of the 11/23s.
>  
> Unfortunately, after mounting and LOADing a known good disk cartridge, 
> neither drive
> from the 'dirty' set will show READY after spinup.  Though the details 

You do have these cabled to a working controller, I trust? You need the 
clock signal from the cotnroller for the drive to spin up and go ready.

> are a bit
> different, each drive emits a very noticeable sound, kind of a 
> whining/rumbling sound
> (not squealing), that I think is indicative of dry bearings in the 
> spindle, the
> spindle motor, or both.  I wonder if dragging bearings are preventing 
> the drive from
> becoming READY due to uneven RPM?
>

It's possible, but unlikely. I suppose you could start by looking at the 
output of the sector transducer (posibly after the amplifier circuit). 
That's what the drive uses as a speed reference anyway (the motor in the 
RL is not locked to the mains, unlike most other demountable hard drives, 
there is no change for 50/60Hz). See if the signal is stable and has the 
right frequency (compare it with the same signal in another working drive).
  
> I've scoured the online documents for possible information regarding RL 
> drive
> lubrication, but I can't come up with anything that suggests 'in the field'
> lubrication options.  The RL01/RL02 Maintenance Guide talks about 
> disassembly and
> Field Replaceable Units, but nothing about lubrication.
>  
> So a few questions for those in the know:
>  
> Could dragging bearings be the cause of no READY indication?
>  
> Has anyone had any experience lubricating the appropriate assemblies in 
> an RL drive?

I would not try to lubricate the spindle bearings. You'll never get it 
apart anyway (t's pressed together, and you have to maintain mecahnical 
balance, etc. There may be a ferrofluid seal in there too). The risk of 
contamination to the disk/heads is too great. 

It shouldn't hurt to take the spindle motor out, take it apart (obvious 
through-bolts) and oil the bearings. I think they're phosphor-bronze 
bushes, not ball races, in which case you want a medium machine oil on them.

> If so, what lubricant is recommended, where is it applied, and how?
>  
> Removing the motor for lubrication is no problem, but I wonder if 
> removing the
> spindle assembly would then necessitate a head alignment once it's back 
> in place?  

No, you can remove and replace the spindle without upseting the heads. In 
any case, the RL drive has an embedded servo burst in each sector header, 
so head alignemnt is quite easy (you need a 'scope, but no special 
alignment disk, any normal disk will do).

-tony




More information about the cctalk mailing list