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From: aronov@acf4.UUCP (Boris Aronov)
Newsgroups: comp.sys.att
Subject: 6300+: hardware going crazy???
Message-ID: <13050017@acf4.UUCP>
Date: Thu, 10-Sep-87 13:26:00 EDT
Article-I.D.: acf4.13050017
Posted: Thu Sep 10 13:26:00 1987
Date-Received: Sat, 12-Sep-87 09:28:50 EDT
Organization: New York University
Lines: 33

Distribution: na
Subject: ATT 6300+: Funny hardware problems

I wonder if anyone can make any suggestions about the following behavior of
my ATT6300+:
	Once (ONLY once), it crashed without any visible reason and failed to
reboot after I reset it. Numerous attempts to reboot UNIX via 'reset' button
yielded a huge variety of different ROM diagnostics errors, some of which
are described below:
1. Memory test would show 896K instead of the 1024K I have in the machine.
2. Memory fault somewhere in low memory (after it gets past 256K), after
which it cannot find the hard disk drive (says 'Hard disk', but never
prints 'READY')
3. DMA Control Fail : 04 (this occurred only once...)
4. Memory fault in yet another part of memery (somewhere around 128K).

At some point I managed to go through the ROM diagnostics and run disk-based
diagnostics: it showed all systems are OK, except for memory parity errors.
Every time I would run the memory test, I would get a parity error in an
entirely different part of memory.

NOW for the funniest part: I ran the diagnostics once more, and it did NOT
find anything--memory faults or otherwise. Since that point I've been running
the machine without any problems whatsoever.

			WHAT'S GOING ON???

					Any comments would be appreciated.

					Boris.
					...cmcl2!acf4!aronov
					aronov@acf4.nyu.edu
					aronov.acf4@nyu.csnet