Apple Issues Fix for Flakey Mac II Hard Disks
 
Microbytes Daily News Service
Copyright (c) 1989, McGraw-Hill, Inc.
After numerous reports of Quantum hard disks failing in Mac II
computers, Apple has issued a statement saying that Apple and
Quantum have "investigated the problem and have developed a
solution." The problem has occurred with 3.5-inch 40- and
80-megabyte drives in some Mac IIs.
 
Symptoms include periodic failure of the system to boot and the
appearance of a dialog box during operation that says "Can't
Load Finder." If turning the power off and on again does not
fix the problem, the system might be a candidate for the fix
that Apple has announced.
 
Apple and Quantum have attributed the problem to increased
viscosity of the shaft lubricant in high humidity, preventing
the disk from rotating at full speed. They say the problem can
be alleviated by changing the hard drive's programmable ROM.
The fix consists of a new ROM set that torques the actuator and
spindle of the drive harder during startup; this overcomes the
increased viscosity of the shaft lubricant in higher humidity,
the companies say.
 
Apple has sent a note to its dealers stating just which HDAs
(hard drive assemblies) are eligible for repair. According to
Apple, "Any HDA that has PROM Version 7.9 01 or earlier located
on the hard disk controller board and has variation codes 0032,
0034, or 0058 should have the PROM replaced with PROM Version
TA.2 01 or later. The variation codes are located on a small
barcode label in the upper right corner of the drive near the
50-pin SCSI connector."
 
This Repair Extension Program will be in effect until October,
1991, Apple says. Customers who have had out-of-warranty
repairs to their Quantum drives since April 1989 should call
Apple Customer Relations at (408) 252-APPL for further
information.
 
While Apple is asserting it has fixed the problem with this ROM
change, some Mac owners question how this program will be
implemented and whether all affected drives will be brought to
dealers for service.
 
Omar G. Barraza, technical support specialist for MicroNet
Technology (Irvine, CA), thinks the ROM change alone will not
fully solve the problem. He says inadequate drive venting will
allow high internal humidity to accumulate when the drive is
powered down. This humidity could contribute to media
degeneration, he told Microbytes Daily.
 
                              --- Larry Loeb
 
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