rleyden@pnet02.cts.com (Richard Leyden) (09/04/88)
I'm have a hard disk failure which is interesting because it suggests
levels
of complexity to the hard disk I hadn't appreciated before. I have a Wedge
board connected to a Miniscribe 3650.
After a local power failure at my house, on powering up the hard disk
would spin up for a few seconds, access the heads, then the LED would flash
red in sort of a Morse code pattern that I took to mean "D-E-E-P
T-R-O-U-B-L-E". Normally the hard disk goes through this sequence but ends
up with a green LED. On the Amiga side everything would be fine until
trying to read from the disk, then the system would just lock up.
Disconnecting the controller card from the drive had no effect so it seems
the problem is within the drive itself.
I removed the drive from the case and powered it up while watching the
head positioner shaft. The shaft rotates and has a flange which seems to be
some sort of position detector. On powering up the flange moves to a
position between two stationary posts. If the shaft is manually rotated
away from this position when the power is off, it moves back during the
power up sequence. I happened to rotate the shaft past the posts so that on
power up it was one complete turn beyond where it had been. The green LED
came on and the drive worked perfectly for a couple days (2-3 power up
cycles) and then the red flashing LED returned. I had used the "park"
command the last time before turning off the power.
I don't really want to have to take the hard disk out of the case each
time I power up, however it seems that the going rate for hard disk repair
is about $130-150. I was wondering if there is some way the Amiga could
issue low level commands to drive causing the heads to move back to a range
where it will work on its own.
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