Space, the next frontier

From: Dwight Elvey <elvey_at_hal.com>
Date: Mon May 24 14:12:46 1999

ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
> And it's getting
> ever harder to get working ST506 drives.

Hi
 The biggest trouble with these drives is that the head
stepper has a limit arm right where fools can get at
it. Wipe the arm back and forth once, with the disk
stationary, and you've made a nice groove in the surface.
The other thing is on the braking of the spindle. Some
used a mechanical brake but others used dynamic braking.
The ones with dynamic braking are real sensitive to
having the heads drag backwards because of rotational
inertia. Both of these are handling issues. It does
help to alway park the heads on the far end before
moving the machine that has one of these drives. When
removing, one should also tape a piece of cardboard over
the steppers end so you don't bump the sector limit arm
and move the heads sideways. Some also have spindle locks
but be real careful to watch the rotational direction.
Turn the spindle the same way that it normally runs, only.
 The reason these two things cause so much trouble is that
the back side of the heads have a real sharp edge. It tends
to dig into the disk like a carpenters plane.
 If your old setup doesn't have a head park routine, I
would highly recommend that you write one. I recommend
that you always park the heads every time before you power
off. I have several 506's that are still running and
have many hours on them.
Dwight
Received on Mon May 24 1999 - 14:12:46 BST