10 Jan
2010
10 Jan
'10
6:51 p.m.
Tony Duell wrote:
Ah no. In the full height one, the eject mechanism will normally still
move if you press the button, but the latching pawl dowsn't drop into
place. So the disk holder -- and upper head -- go down again when you
release the button. if the disk is partially ejected when this happens,
it's almost certain the top head will be ripped off the gimbal.
There are some photss in my filckr account (tony_duell) of this drive in
bits.
As an aside, this is a major problem on the
full-height Sony 3.5" drives.
They were originally lubricated with a grease that turns hard and sticky
with age. The result is that the eject mechansim doesn't lock in the 'up'
posiiton properly. When you try to eject a disk, the upper head will
catch in the slot of the disk itself and will be ripped off the gimbal
spring. This drive was used in a lot of HP devices, if anyone has ole HP
3.5" stuff and hasn't cleaned off the grease, do so _now_ before you
haveto ifind a new head assembly and align it!
Sounds similar to what happened with this one -- I had to extract the
disc by opening the drive up and manually forcing the eject mechanism to work. Unfortunately I pushed the slider too far and
knocked the top tray
off the mounting. When I put it back in, I suspect I hit the top head
and either broke it or knocked it out of alignment.
Does the gimbal spring (the spring leaf that uspports the upper head)
look bent or distorted? It is quite delicate, although often bending it
back so it looks flat will get the drie working again.
TBH, the
timing histogram from the Sony drive's upper head looks like
Do you mean 'upper head' or 'side 0 head' here? An open-circuit head will produce noise, as will
anything that causes it
not to be connected to the read amplifier.
What's odd is that there seems to be some data there -- one or two
sector headers occasionally decode OK, so maybe the head is just out of
alignment. That, alas, is nothing like the drive I am
thinking of. Mind you, the
drive I was thinking of is a 720K one (actually the version I know is a
80- cylinder, double hard _600 rpm_ unit, but it came in all sorts of
versions.
That sounds like the drive in my HP 1651B logic analyser...