> On Apr 8, 2019, at 6:11 PM, Charles via cctalk <cctalk@classiccmp.org> wrote:
>
> 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
contamination.
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?
paul
