On 6/6/17 11:56 AM, Paul Koning wrote: > >> On Jun 6, 2017, at 2:26 PM, Al Kossow via cctalk <cctalk@classiccmp.org> >> wrote: >> >> >> >> On 6/6/17 6:10 AM, Philipp Hachtmann via cctalk wrote: >> >>> And I have cables and lots of spare heads: All submerged since Saturday. I >>> most probly won't try to recover the packs >> >> If they really are that rare you may want to reconsider. > > Agreed, and packs from the 2311, RP03, RK05 era are washable. The binder/oxide is quite thick on them. The only thing they can't survive is surface damage that roughens the surface to the point where the heads crash. I had a couple I was working on recently where the plastic catch broke that held the spring for the door flap and that gouged up the first 1/2" of the top surface. I wasn't very happy, since the rest of the surface was clean.
I hadn't realized it before, but the 2nd generation (2200bpi vs 1100) doesn't have write precompensation, and there are some real kludges in the read recovery circuit to deal with pulse crowding. This appears to be particularly troublesome on the inner tracks. Tuning this is a real PITA, especially on drives used for Altos, which pack extra bits on the sectors for a tag field.
