Sticking RL02 positioner
charlesmorris800 at centurytel.net
Mon Apr 8 18:29:53 CDT 2019
From: Paul Koning
Sent: Monday, April 08, 2019 6:26 PM
To: Charles ; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Sticking RL02 positioner
> On Apr 8, 2019, at 6:11 PM, Charles via cctalk <cctalk at classiccmp.org>
> One of my RL02 drives (that sat for a long time) has developed what
> appears to be a sticky head positioner.
> But it's only a problem going from the full-retracted position to loading
> track 0.
> Once it's loaded, the drive will pass all seek and read/write tests.
> It takes a surprising (to me) amount of force to pull the heads out into
> the disk area (power off, no pack). When they're out there, the arm slides
> back and forth easily.
> Sometimes it won't load at all - push the load button, light goes out,
> disk spins up to what sounds like normal speed, but the heads never move
> and the Ready light doesn't come on.
> There's supposed to be a Fault after 40 secs but that doesn't happen -
> it'll sit there forever spinning but not ready.
> If I turn off the power and remove the pack, and pull the positioner out
> just enough to avoid opening the Heads Home microswitch (which causes a
> Fault light), then it'll spin up, load track 0, and work fine the rest of
> the day.
> The manual (as usual) only recommends replacing the bad assembly for ease
> in field servicing, which is deliberate.
> But I don't have a DEC repairman and a warehouse full of parts handy... Is
> there some kind of adjustment or lubrication I can do?
Lubrication in a disk assembly sounds like a thing to avoid because of
I don't know the RL02 specifically, but some pack type disk drives have a
"head unload ramp", a wedge shaped device that lifts the heads away from the
platters when the positioner retracts to the unload position. I wonder if
there might be dirt on those that could be cleaned with a suitable cleaner
(kimwipes or similar lint free cleaner) and solvent (96% isopropanol comes
to mind). Does the book give any guidance about this sort of thing?
Yes, I am sure there is such a ramp, since the heads do move close together
when the positioner extends. I can feel it "wedging".
I'll take another look at it, when I have obtained some lint-free wipes or
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