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From: csrobe@ICASE.EDU (Charles S. [Chip] Roberson)
Newsgroups: comp.sys.atari.st
Subject: Supra 20meg HD woes - Part III
Message-ID: <8904240318.AA09120@icase.edu>
Date: 24 Apr 89 03:18:16 GMT
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WARNING:  Long message follows, but please read it, I need help!

Many of you probably remember me from the summer of 1987 when my
Supra 20meg went unreliable on me -- it would sporadically speed
up and then park itself.  I spent from June of 87 until
May of 88 trying to get it fixed.  They replaced it in May.  It
then sat in storage for 6 months until I moved in October.  Recently
my new one has been acting up.

The original one had two problems:  1) the speeding up and 2) the
parking.  The problem manifested itself on a hot June summer day
and persisted for some time.  Since I wasn't sure if I had one or
two problems I don't remember details that well.  However, I do
remember beng able to reproduce some sympton both with my HD
disconnected from my ST and with the HD standing alone in the store
where I bought it.  After 10 months they finally replaced it and I
thought my troubles were over.

As I said my HD was unused for all of the Summer of 1988.  It served
me fairly well through winter but I did notice an occassional parking.
I don't remember how many times it occured but it was rare enough
that I didn't want to start another round with Supra and ACA (the
retailer).  Anyway, as the temperature is getting warmer and warmer
the problem is showing up more.  Today, was the hottest day so far
this year and it was the worst day for my HD -- it was basically
unusable.  [Now, I have to put in a caveat here -- I did take the
cover off to look inside for part numbers and I picked the HD up
for the first time in several months.  This may have been a trigger.]

Anyway, the HD is parking itself -- it does NOT exhibit the symptom
of the sporadic speed up.  During normal operation the HD just decides
that it doesn't want to spin any more and spins down.  The busy light
will flash for a while and then stops.  Sometimes it will spin back
up just to park itself again.  Sometimes it will start to spin back up
but park itself before it gets to full speed.  I've tried turning it
off and turning it back on with no consistent effect -- sometimes
it starts as it should, othertimes, it just sits there, not spinning.

The busy light flashes at about 2 flashes per second and sometimes
becomes erradic.  Sometimes it just stops flashing all together.
After it has stopped flashing you will hear an occassional tick
or buzz and either the hard disk will attempt a spin up or the
busy light will start to flash irregularly.

All of this happened with:
     o the HD connected to ST
     o the HD disconnected from the ST
     o the HD disconnected from the ST and the cover off to help
       ventilation.

Currently I suspect that the drive has one of the three problems:

1) It is extremely sensitive to either heat, humidity, or both.
2) It has a loose connection or my ST likes to fry some part of
   Supra drives to make the park themselves.
3) or, my cordless phone is messing with my HD as well as my phone
   line.

I know that last one sounds preposterous, but I'm not beyond doubting
it.  I have an AT&T cordless phone which goes crazy at various times
according to what is being displayed on the screen.  For example, a
window could open or I could be returning from gulam and my hand set
will start chattering with all kinds of noise.   Other times, my
hand set can be off and my base unit will start sending trash through
my phone line and completely mung a connection.  Is there anyway that
radio frequencies could cause my HD to act in this fashion?

I am going to move my phone out of the room and see if that has any
effect.  I know it will at least stop 1 aggravation -- the chattering
handset!

Anyway, my strongest suspect is heat -- the HD has NO fan!
So I am looking into getting and ICD FAST hard drive case with
the cooling fan and other nice features.  Can I rip the following
hardware out of my Supra case and shove it into an ICD?  If I
eventually want to add a second drive can I?  What kind is necessary?

Hard Disk Type:     Miniscribe 8425s
Controller Type:    Miniscribe 8425           

Well that's basically my problem.  Can anybody out there share any
speculations on what is causing the problem and propose some solutions.
Will I be wasting my money (what precious little is left) by getting
the ICD FAST hard drive case?  As you can tell, I am not an electrical
engineer so I have to rely on those of you who are.  How should I
attack this problem?

Please can anybody help me?

Here are some specs from the Supra format utility (supfmt.prg):
SPECIFICATIONS:
     Heads:              4
     Cylinders:	         612
     Sectors per track:  17
     Interleave:         1
     Reduced write:      612
     Write pre-comp:     612
     Landing zone:       4
     Step pulse rate:    2
     Reserved tracks:    40
     Map bad sectors:    NO
     Removable Media:    OFF
     Forced partitions:  NO

I thought somebody might find these useful.  Anybody willing to add
some meaning to some of these specs, like "reduced write" and "write
pre-comp"?

Again, I would like to appologize for the length of this article
but I really need help.  All comments will be GREATLY appreciated!

Thanks,
-c


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|Charles S. Roberson          ARPANET:  csrobe@icase.edu                  |
|Dept. of Comp. Sci.                    csrobe@cs.wm.edu                  |
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