13 Apr
2000
13 Apr
'00
1:06 p.m.
When they say "do not lubricate ..." they're not lying! The grit and grime
that finds its way into the leadscrew will act as lapping compound and
abrade the lead screw, which in most of the newer lead-screw-driven
mechanisms is plastic, and soon, you'll have a drive with too much backlash
on the lead screw, which will result in positioning error, depending on the
direction in which the lead screw was last moved. I would probably feel
comfortable cleaning out the gunk with a penetrating oil wuch as what you
mentioned, but I would vigorously pursue the problem of getting the rest of
the sticky residue out with a volatile solvent.
That, in turn, threatens to soften the plastic head-assembly, part of which
is the "nut" for the lead screw, so don't get any of the benzene or methyl
alcohol, or acetone, on the plastic parts, lest they soften and change their
shape.
I'd suggest that you look at the service manual and consider whether this
bothers you enough to warrant going through the painstaking process of
disassembling and cleaning the head transports in order to get rid of the
grease. If you're careful, you might find a way to brush out the threads,
but they'll continue to accumulate dirt and grit so long as you have grease
on the "nut" which is part of the head assembly. The only sure way is to
disassemble and clean them such that they don't have a place for the grease
to hide.
Dick
----- Original Message -----
From: <CLASSICCMP(a)trailing-edge.com>
To: <classiccmp(a)classiccmp.org>
Sent: Thursday, April 13, 2000 10:53 AM
Subject: Lubing Shugart 800,801's?
I've been sorting through a large pile of Shugart
800's and 801's here,
and many of them have goo on the head stepper lead screw. It looks
like white lithium grease, undoubtedly put there by a previous owner
or all-thumbs tech, as the Shugart manuals say (section 3.3):
Do not lubricate the SA800/801; oil will allow dust and dirt to
accumulate.
However the goo got there on the leadscrew, it's so thick now that it's
quite difficult to turn it - not only is the stepper motor not up to the
job, I can barely turn it by hand in some cases.
I have found that "Liquid Wrench" (yes, that stuff you get at the auto
parts store) does a pretty good job of at least softening the goo
temporarily,
enough so that I can actually run the drive through
diagnostics,
but eventually the solvents evaporate and I'm left with thick goo. Is
there an easy way to clean this goo off without completely disassembling
the stepper motor/leadscrew assembly and doing the subsequent realignment?
I can go in and do a half-assed job of cleaning the goo off the threads
with Q-tips and skewers, but there's really a lot there and this doesn't
get it all.
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927