Help needed on HP 7900A disk drive (mechanical)

From: Jay Jaeger <cube_at_msn.fullfeed.com>
Date: Thu Jun 17 20:47:17 1999

Could be a lot of things.

>"Problem":
>I put the cartridge in the drive and hit load. You can hear the spindle come
>up to speed. Exactly 30 seconds later as stated in the operators guide, you
>can hear the heads move and then the drive ready light comes on. From what I
>understand if there are any problems at all up to this point, the drive
>fault lite would come on (including a seek fail, etc.). I kept my finger on
>the unload switch. The second the heads came out I could hear a
>disconcerting noise. I immediately hit unload. I removed the cartridge, and
>inspected both the cartridge and heads carefully. No obvious signs of

You might have some head to disk interference on the disk platter. I have
an HP 2870
(IOMEC 1012) drive. It had the cartridge in it when I got it, but also had
a really messed
up power sequencer, which I finally got fixed early this year.

The disk surface was simply grimy. I took it all apart, and used medical
grade Isopropyl
with the good ole RK05 disk cleaning wand and cleaned both the fixed and
removable
disks. (They were so dirty there was simply no choice, which made it
easier to, umm, swallow).

Also, there was a little piston mechanism for loading unloading the heads.
It was really
badly gummed up. I tested it _before_ I spun up the drive, because I too
wanted to make
sure I could unload the heads quickly. If that is sticky, the heads cannot
load properly.

Generally, my heads loaded quietly. However, after I got the controller et
al hooked up, I
started doing some seeks. When I seek in close to the center of the disk,
I can hear the
"tinkling" or "pinging" noise of head to disk interference. Not a full
crash, but not desirable
either. I can also hear some interference when I unload the heads.

Also, my belt was in really bad shape. It had caused considerable
corrosion on the motor
shaft. Had to file the gunk off.

Or, your spindle or motor bearings may just be dry. So

   - Check the cleanliness of your fixed platter (and heads)
   - Check your belt, fans, blowers, etc.
   - Check your bearings

(The latest on mine is that when I actually try to do I/O, there is no data
transferred. The DMA
diagnostic on my HP2114 does not seem to run properly, so it looks like I
have some work
to do -- probably not until this fall, though).

>problems. I reloaded the cartridge. This time, when drive ready lit up, the
>drive was nice and quiet for about 25 seconds. Then I started hearing the
>noise again. On and off, more and more, so I hit unload. Rechecked the heads
>and cartridge again - no obvious signs of damage. Tried loading the
>cartridge again. This time it ran for a few minutes before I heard the
>noise. I unloaded and rechecked everything, still no signs of problems.
>Gee - can you tell I'm paranoid about possibly ruining the new cartridge
>and/or the heads? :)
>
>The sound is not quite metallic, but very close. It sounds like something
>rubbing at high speed but at a pretty high pitch. The best way I can
>describe it is that it is almost identical to the sound an 8" floppy disk
>makes when you put it into an RX02 drive and close the door (the media
>turning inside the sleeve), but much louder. I'm pretty uncomfortable
>proceding with diagnostics, etc. unless someone here can calm my fears as to
>what the sound might be. Is it just due to the fact that it's a brand new
>cartridge, or is it indicative of a potential head crash, just a belt issue,

>dust, etc? I'm pretty familiar with the whine a drive makes when the
>bearings are going out, and it does not sound like that sound.
>

I would clean that fixed platter (assuming this disk has one).

>Any help, ideas, thoughts, etc. are MOST appreciated!
>
>Jay West
>
---
Jay R. Jaeger The Computer Collection
Jay.Jaeger_at_msn.fullfeed.com visit http://www.msn.fullfeed.com/~cube
Received on Thu Jun 17 1999 - 20:47:17 BST

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