Service manual

Chapter 4 Diagnostics
38
Test Description
Interrupt Controller Test
Tests the interrupt masks. Test failure at any point causes an error code to be
displayed.
RAM Address Line
Independence Test
Verifies the address independence of real-mode RAM (that address lines are
not stuck together). Test failure causes an error code to be displayed.
Real-Mode Memory Test
(First 640 K)
Read/write test on system real-mode RAM. The test checks each block of
system RAM to determine how much is present and displays the current base
value upon successful completion of the test. Test failure of a 64 K block of
memory causes an error code to be displayed and the remainder of the memory
test to be skipped.
Shadow RAM Test
Tests Shadow RAM in 64-Kbyte segments, except for the segments beginning
at A000h, B000h, and F000h. If they are not being used, segments C000h,
D000h, and E000h are tested. Test failure causes an error code to be
displayed.
Real-Time Clock Test
Checks the real-time clock registers and performs a test that ensures the clock
is running. Test failure causes an error code to be displayed.
Keyboard Test
Invokes built-in keyboard self-test of keyboard's microprocessor and tests for
stuck keyboard keys. Test failure causes an error code to be displayed.
Mouse Test
Invokes built-in mouse self-test of mouse's microprocessor and tests for stuck
mouse buttons. Test failure causes an error code to be displayed.
Flexible Disk Controller
Subsystem Test
Tests for proper operation of the flexible disk controller. Test aborts after the
first or is found and will not test any further. Test failure causes an error code to
be displayed.
Internal Numeric
Coprocessor Test
Checks for proper operation of the numeric coprocessor part of the processor.
Test failure causes an error message to be displayed and the boot process to
abort.
Serial Port Test
Tests the two embedded serial port registers. Test failure causes an error code
to be displayed.
Parallel Port Test
Tests the one embedded parallel port, if it is enabled. Test failure causes an
error code and an error message to be displayed.
Hard Disk Subsystem
Test
Tests for proper operation of the hard disk controller and performs a read-verify
of a sector on the disk. Test aborts after the first error is found and will not test
any further. Test failure causes an error code to be displayed.
System Configuration
Tests
Checks for configuration errors and checksums accessory ROMs. Test failure
causes an error code to be displayed.
Beep Codes
If the POST routines cannot display messages when an error occurs before the video display is initialized,
the server emits a series of beeps. This means that if on boot you get a blank screen, but hear beeps, you
should refer to the table below to interpret the beeps.
Beep Codes for Fatal Errors
P = Check and replace processor board
S = Check and replace system board
M = Check and replace memory modules
R = Replace ROM chip