aronov@acf4.UUCP (Boris Aronov) (09/10/87)
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
dave@westmark.UUCP (09/13/87)
In article <13050017@acf4.UUCP>, aronov@acf4.UUCP (Boris Aronov) writes: > Subject: ATT 6300+: Funny hardware problems > I wonder if anyone can make any suggestions about the following behavior of > my ATT6300+: ... > yielded a huge variety of different ROM diagnostics errors, some of which ... > 1. Memory test would show 896K instead of the 1024K I have in the machine. > 2. Memory fault somewhere ... > ... cannot find the hard disk ... > Every time I would run the memory test, I would get a parity error in an ... > 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. My 6300PLUS used to power itself down (everything except the fan) and would then come up in a strange mode with the hard disk invisible and the memory full of errors, etc. Powering it down for about 30 seconds left all systems working fine. The power supply would crowbar (about once every other month) and if it was powered down for a second or so, it would come up with strange voltages where +12 belonged. Power it down for a longer time, all is well. Finally, I got tired of this behavior, and called AT&T's hotline. They recommended replacing the power supply, and advised that a new model is available. My PLUS came (2 years ago) with a model LA16 power supply. The new model is called LA16B. I have had the new one installed for a month or so, with no problems, so far. To get the new power supply, call AT&T National Parts Sales (800 222 PART) and if your machine is out of warranty, give them a credit card number. The new supply costs $100 with the old one in exchange. -- Dave Levenson Westmark, Inc. A node for news. Warren, NJ USA {rutgers | clyde | mtune | ihnp4}!westmark!dave