13 Apr
2000
13 Apr
'00
1:25 p.m.
When they say "do not lubricate ..."
they're not lying!
If only the previous owners/techs had understood this!
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've got 14 Shugart 800's and 801's from this latest pile now undergoing
the DSD Hyperdiagnostics simultaneously (lots of head kerklunking!)
and I see no evidence of alignment problems on any of them. I'm strongly
of the opinion that 95% of alignment problems are created when folks go
in and fool with the alignment when there's nothing wrong in the first
place.
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.
I think "Liquid Wrench" is both a penetrating oil and a mix of volatile
solvents. And in spraying it in I added my own oil to the lubricating
mess that shouldn't be there, but now at least I can turn the leadscrew and
run the drives through their paces.
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 appreciate that, I learned long ago to test chemicals against plastics when
a can of TV tuner I had dissolved the plastic shaft in an old TV...
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.
Yes, I can do a halfway decent job with skewers and Q-tips to get the goo
out of the threads, but there certainly is some still left in the threads
on the head assembly/pre-load nut and that I can't get at without
removing the whole assembly and destroying the (currently fine) alignment.
Tim.