Xref: utzoo comp.sys.att:2393 comp.sys.ibm.pc:11416
Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!lll-tis!mordor!sri-spam!rutgers!mtune!whuts!prn
From: prn@whuts.UUCP (NEWELL)
Newsgroups: comp.sys.att,comp.sys.ibm.pc
Subject: Re: Serial port problems on 6300
Message-ID: <3693@whuts.UUCP>
Date: 4 Feb 88 14:24:02 GMT
References: <2742@sfsup.UUCP>
Organization: AT&T Bell Laboratories
Lines: 12
Summary: Check the power supply!

In article <2742@sfsup.UUCP>, jerry@sfsup.UUCP (Jerry Theisen) writes:
> I have an AT&T PC 6300 that has worked without a problem for 2 and a half
> years.  Now for some reason, the serial port has up and died.
> These are the symptoms:
> 
I had the same problem on a 6300 once.  The cause was a failure in the
-12V output of the power supply.  I opened the supply to find a cold
solder joint on the -12v regulator.  It cold also be a failed line driver
chip.  These chips are not tested by the standard diagnostics.
Good luck.

					Paul Newell
					whuts!prn