warped RK05 pack -- lost cause?

[Noel Chiappa]

    > From: Fritz Mueller fritzm at fritzm.org 

    > I'm assuming that if I had to release the media from the hub in order
    > to true it, its value as an alignment cartridge would be lost anyway.

Yes and no.... The RK05 alignment pack is mostly to make sure that the fine
lateral track adjustment is correct (i.e. that when the head thinks it's over
track 0, it's _really_ over track 0).

However, there's also rotational alignment (i.e. start of sector), which is
done with the slits in the ring on the pack (so yes, releasing the media from
the hub in an ordinary pack will make that pack unreadable - at least until
it's reformatted). There is an index/sector timing adjustment procedure, and
it uses the alignment pack too, but this rarely needs to be done.

Still, if the platter is on wrong, the whole thing's useless anyway. So as
long as the platter goes back exactly concentric (and I'm unsure of how the
mechanical alignment works, there may be something to assure there's no
runout), it should still be usable for the head alignment. (To use it for
sector alignment, you'd have to ensure that the drive is aligned for this
before-hand, then use it to align the pack.)

But check the RK05 Maintenance Manual (EK-RK5JF-MM-001), and see if there's
anything I missed. There's also an 'RK05 Subsystem Maintence Course' document
(EY-D2055-WB-001) which might contain some useful info.


Off to look at the V6 MMU setup code! ;-)

	Noel