Path: utzoo!utgpu!watserv1!watmath!uunet!lll-winken!scooter!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: unix-pc.general
Subject: Re: Dying machine?
Summary: All four LEDs on should not happen
Message-ID: <1872@neoucom.UUCP>
Date: 14 Jan 90 21:04:56 GMT
References: <1057@kosman.UUCP> <4414@rayssdb.ray.com>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 45


All four LEDs on and some weird pattern on the screen should not
normally happen.  It sounds to me like the reset pulse generator is
failing to provide a satisfacotry initial reset if that is
happening.

Here is a brief description of the boot ROM test and initialization
sequence:

There are four LEDS on the left side visible though the vent slots
below the keyboard platform.  The LED nearest the back of the
machine is the most significant bit.  Off=0, On=1.

Test #1 ( 0 0 0 1 )
This pattern lit and no boot means failed to initialize telephone
hardware

Test #2 ( 0 0 1 0 )
Failed video RAM test.  A lace pattern may appear briefly on the
monitor while this is running if the CRT is warmed up.  The video
test uses an incementing write to vid ram and reads back the
address.

Test #3 ( 0 0 1 1 )
Failed page map ram test.

Test #4 ( 0 1 0 0 )
Fialed to set map ram to unity mapping.  The system tries to
initialize the virtual memory map to point at physical memory pages
with a state of page present, write enabled, not written yet.

Test #5 ( 0 1 0 1 )
Failed dynamic ram test

Test #6 ( 0 1 1 0 )
Failed system initialization

Test #7 ( 0 1 1 1 )
Could not find loader on disk.  This is the part where the small
squares appear starting at the upper left corner of the screen
until the system is able to find a loader on one of the disks.



Bill