The head cable connectors were color-coded depending on the drive they
were manufactured for...either 793X or 792X. I don't recall which was
which, but there were green connectors and yellow connectors on the new
heads. I think the green ones were for the 792X drives and the yellow
ones were for the 793X drives, but it could be the other way.
Something else you may have run into, was the 7933 head assembly getting
stuck to the "crash stop". If the drive thought the heads might be
about to crash, such as during a power failure, the actuator would do an
emergency retract to get the heads off of the platters to prevent a
crash. The actuator would retract the heads really fast and the head
assembly would come to a rest when it hit a foam pad called the "crash
stop". With age, the foam pad started to deteriorate and became sticky
(like the foam sound abatement for a 256X printer). When a 7933 with a
sticky crash stop experienced a power failure, the actuator assembly
would retract back fast and get stuck to the foam. When power came back
on, the heads wouldn't load because they were still stuck to the crash
stop. A quick flick of your finger was all it took to get the heads
rolling on their rails again. What was HP's solution to fix this?
Answer: apply talcum powder to the foam pad, being sure to dust it off
good to minimize the amount of powder that could find its way into the
disk chamber.
Then there's the time I pull-started a 7933 spindle motor using one of
my shoe strings, like pull starting a lawn mower. The 7933s ran for a
long time and the ball bearings in the motor heated up. When powered
down for a PM, they cooled. Sometimes when trying to spin them back up,
they wouldn't get up to speed quick enough during the self test so the
self test would fail, not allowing the drive to be used. I removed my
shoe string, wrapped it around the large nut on the bottom of the disk
pack spindle motor, turned on the drive and pulled as hard as I could to
help the motor get up to speed. It worked. Spindle motors didn't fail
that often, so we didn't stock one in our HP office. Once the drive was
up to speed and passed its self test, the drive could be used for a few
days while I ordered a spindle motor to replace the defective one.
Regards,
Steve Gray
Abtech Support
-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
Behalf Of Denys Beauchemin
Sent: Thursday, March 06, 2008 9:26 PM
To: [log in to unmask]
Subject: Re: [HP3000-L] HP7933 - Was: newbie question -storing a file
from tape to disk -
I believe you are correct. They had to color-code them. I remember the
jockeying for position to get these heads, what a screw-up that was.
Does anyone remember when HP got out of the disk drive business? I
think it was around 1995.
Denys...
-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
Behalf Of Joseph Dolliver
Sent: Thursday, March 06, 2008 5:14 PM
To: [log in to unmask]
Subject: Re: [HP3000-L] HP7933 - Was: newbie question -storing a file
from tape to disk -
Yeah, they were called green heads as I think.
Huge fail rate, kept HP busy for months replacing them all
>From: Gary Robillard <[log in to unmask]>
>Date: 2008/03/06 Thu PM 03:10:42 CST
>To: [log in to unmask]
>Subject: Re: [HP3000-L] HP7933 - Was: newbie question -storing a file
>from tape to disk -
>Since the 7933/35 topic seems to live on...
>
>The head problem didn't cause disk crashes, but was a problem where the
>head cables would become intermittent and finally would lose their
>connection, causing read/write problems (if you were writing when the
>cable quit, you now had bad data on your disk). That is what prompted
>the badsectr utility which was originally written for MPE/V.
>
>The 7933 was released because they couldn't get the seal right in order
>to prevent contamination from entering the disk pack when it was
>changed, so the door unlock was defeated and it was a 'fixed' pack.
>Once the seal problem was fixed, the 7935 was released with the 'door
>open' switch operable...
>
>Thanks,
>
>Gary Robillard
>
>
>
>-----Original Message-----
>From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
>Behalf Of Gilles Schipper
>Sent: Thursday, March 06, 2008 11:36 AM
>To: [log in to unmask]
>Subject: Re: [HP3000-L] HP7933 - Was: newbie question -storing a file
>from tape to disk -
>
>If my memory serves me correctly, some time after the 7933 was
>announced and became quite popular, HP had a massive "recall" in order
>to change faulty heads that were causing disk crashes.
>
>This required CE's to replace the heads on any affected 7933 at the
>next opportunuity - usually the next preventative maintenance call.
>
>Now here is where my memory may be a bit fuzzier, but I seem to recall
>that around that time, HP announced the 7935, which was exactly the
>same as the 7933, but was modified to permit the user to replace the
diskpack itself.
>
>(Perhaps the 7935 was the original and the 7933 was the one with
>user-replaceble disk packs.)
>
>-----------------------------------------------------------------------
>-
>Gilles Schipper
>GSA Inc.
>HP System Administration Specialists
>300 John Street, Box 87651 Thornhill, ON Canada L3T 7R4
>Voice: 905.889.3000 Fax: 905.889.3001
>email: [log in to unmask] web: http://www.gsainc.com
>-----------------------------------------------------------------------
>-
>
>---------- Original Message -----------
>From: "Bob J." <[log in to unmask]>
>To: [log in to unmask]
>Sent: Thu, 6 Mar 2008 13:20:14 -0500
>Subject: Re: [HP3000-L] HP7933 - Was: newbie question -storing a file
>from tape to disk -
>
>> As we travel down memory lane............
>> CEs were supplied a hoist to attempt installing & servicing the upper
>> 7933 drives.
>> That setup never seemed safe for anybody within 20 feet of the racked
>> drives.
>> Sleuth was fun for the Series II/III. SleuthSM (simulator) was nice
>> for
>the
>> HP-IB systems. Those utilities that did the actuator "butterfly" test
>> would usually pass through the resonant frequency of the drive to
>> make some scary noises.
>>
>> Bob J. -- Ideal Computer Services
>> http://www.icsgroup.net
>>
>> Jeff Kell wrote:
>>
>> >>>
>> >>
>> >>
>> >> Does anyone recall the "rack-mounts" for stacking 7933s? Anyone
>> >> else ever "race" 7933s across the DP centre floor by judicious use
>> >> of adager or fcopy?
>> >
>> >
>> > 'Sleuth' on a 7920/7925 could produce some very humorous results.
>> > Don't recall that utility making it beyond the Series II/IIIs
though.
>> >
>> > Jeff
>> >
>> > * To join/leave the list, search archives, change list settings, *
>> > * etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>> >
>> >
>>
>> * To join/leave the list, search archives, change list settings, *
>> * etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>------- End of Original Message -------
>
>
>
>* To join/leave the list, search archives, change list settings, *
>* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>
>* To join/leave the list, search archives, change list settings, *
>* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
joseph dolliver
e3k solutions , inc
41630 marie court
leonardtown, md 20650
301-475-6985
* To join/leave the list, search archives, change list settings, *
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