I've got an old Segate 80meg MFM that exhibits similar symptoms, it spins 
up, does the startup check and then without warning shuts down after about 
30 sec.

Talking to one person, they seemed to remember that these drives would 
startup, and do a read of the bootsector.  If the bootsect was unreadable, 
or there was a problem, the drive would spin back down (I don't claim to 
understand the logic with this).  However don't dismiss the possibility a 
capacitor has gone or something.


jam
 ----------
From: owner-port-vax
To: Paul A Vixie
Cc: port-vax
Subject: Re: Anybody know any secret hardware voodoo?
Date: Wednesday, June 14, 1995 12:38AM

>The RD53 does not have motor control.
>It sounds like you are putting too much
>stuff on a BA23's dinky little power
>supply.  Either pull some boards out or
>get a BA123.

hmmmmmmm - interesting thing is - that I don't think there's that much stuff 
 -
the system is configured as follows

1 x RD53
1 x TK50
1 x RD disk controller
1 x TK50 controller
1 x KA630 motherboard
1 x 4 Mb memory card

That's it so far - as an experiment - I tried to get one of the RD53's to 
spin
up at a constant speed on a power supply from an IBM RT Model 135 (Read as
*HUGE* power supply) - and it exhibited the same behavior - spun up - and
immediately spun back down.

 ----------------------------------------------------------------------------  
 ---
 -
Jeremy C. McDermond                             mcdermj@CSOS.ORST.EDU
Technical Analyst                               jeremy@XENOTROPIC.COM
Willamette Industries,Inc.                      #include <Standard 
Disclaimer>
 ----------------------------------------------------------------------------  
 ---
 -