Serial port problems on 6300

[NEWELL]

In article <2742 at sfsup.UUCP>, jerry at 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