ultrasonic cleaning for disk heads

[Fritz Mueller]

Thanks for the tip on heating, Carl.
 
> On Jan 27, 2018, at 11:02 AM, Mark J. Blair via cctalk <cctalk at classiccmp.org> wrote:
> Some dumb questions from a guy who has not yet experienced his first head crash on a removable-pack hard drive:
> 
> When it happens, am I correct in assuming that the pack is toast, and should never be loaded again?

I’m fairly new to this as well, but from what I have seen so far, head crashes vary in severity from mild bumps/scrapes to deep, brutal gouges. My experience with RK05 packs is that media may be recovered after mild crashes with careful cleaning, though it takes a good bit of patience and elbow grease to remove post-crash smudges of burnt oxide from the disk surfaces and the heads.  Anything with a deeper gouge will probably just crash again straight away.

I received about a dozen packs with my RK05 drives.  There is a lot of good advice in the archives here and over on the vcfed DEC forum about opening/inspecting/cleaning packs, and I don’t think I’d try to mount anything in my drives without opening it up and giving it an inspection first.  On RK05 packs this is easy; since they are a single platter you can easily see and clean the entirety of both surfaces.  I imagine on a multi-platter pack it would be really difficult to inspect or clean without unstacking the platters, after which I’d guess alignment and balancing would be problematic?

The dozen or so packs that I received with my drives many years ago had a lot of variation in condition.  Some had bad, hard crashes, others just had “bumps and bruises”.  The heads of both drives as I received them had lots of oxide build up — it doesn’t look as if the previous users (scientists in a lab) had very good disk hygiene!

    —FritzM.