[net.unix-wizards] problems with Kennedy tape drive hubs

hedrick@topaz.RUTGERS.EDU (Charles Hedrick) (04/28/86)

We have a Kennedy 9400 (tridensity) tape drive.  The drive is
generally quite good, except for the supply reel hub.  Every week
or two the tape starts slipping.  There is an adjustment to 
tighten it, but there are limits to how much this can do.  Our
CE tells us that there is a casting inside the hub that sort
of crumbles, and that this hub is inevitably going to continue
being a problem in any operation that uses the drive as heavily
as we do.  (We are not a production DP shop.  We just use it for
backups.  But apparently we do more of them than some places.)
It seems that we are not alone in this problem.  Does anyone
know of a solution?  What I'd love to do is replace the hub
with one of the sort used by DEC.  Does anyone know whether this
is feasible?

ron@mnetor.UUCP (Ron Miller) (05/05/86)

In article <4868@topaz.RUTGERS.EDU> hedrick@topaz.RUTGERS.EDU (Charles Hedrick) writes:
>
>We have a Kennedy 9400 (tridensity) tape drive.  The drive is
>generally quite good, except for the supply reel hub.  Every week
>or two the tape starts slipping.  There is an adjustment to 
>tighten it, but there are limits to how much this can do. 

I have had the same problem.  The cause is poor grip between hub
and reel.  Grip is provided by compressing (and thus expanding)
the little rubber ring.  I found that the ring would not squeeze
out of the hub enough to really grip the reel firmly.  My solution
was to apply lubrication to the O ring.  This worked really well.
No slipping since last treatment (about 6 months as of today), and
the drive is in use daily.

My magic lubricant was a minute amount of 10W30 applied extremely
carefully to the inner surface of the O ring that gets squeezed by
the hub.  The treated portion of the ring shouldn't look oily - just
slightly darker than the untreated portion.  Do *not* get oil on
any other parts or surfaces (especially the outer surface of the
O ring that grips the reel)!

Hope this helps you as much as it has me.

Cheers,
-- 
Ron Miller
UUCP:  {decvax|allegra|ihnp4|linus|utcsri}!utzoo!mnetor!ron
BELL:  (416) 475-8980 ext. 313