NEC Versa 550 Series Service Manual page 106

5-10 Troubleshooting and Repair
Beep Diagnostic
Code
Code
3-1-2 21h
3-1-3 22h
3-1-4 23h
none 25h
3-2-4 27h
None 28h
None 29h
3-3-4 2Bh
3-4-1 2Ch
Table 5-4 BIOS Beep Codes
Description
Master DMA register test
in progress or failure.
Master interrupt mask
register test in progress or
failure.
Slave interrupt mask
register test in progress or
failure.
Interrupt vector loading in
progress.
Keyboard controller test in
progress or failure.
CMOS RAM power failure
and checksum calculation
test in progress.
CMOS RAM configuration
validation for video in
progress.
Screen memory test in
progress or failure.
Screen initialization in
progress.
Test Performed
Pattern test of channels 1 through 3 of
the master DMA controller (starting port
address = C4h). Failure results in a
system halt.
Rolling ones and zeros tests of the
mask register of the master
programmable interrupt controller (port
21h). Failure results in a system halt.
Rolling ones and zeros tests of the
mask register of the master
programmable interrupt controller (port
A1h). Failure results in a system halt.
No specific test is performed - just
indicates that the Interrupt Vector table
is being initialized.
The self-test command (AAh) is issued
to the 8042 (keyboard controller) and
the results are monitored. Failure
results in a system halt.
The power-fail bit in CMOS RAM is
tested and the lower CMOS RAM area
is being checksummed. A failure does
not result in system halt.
No specific test is performed - just
indicates that the configuration
specified in CMOS for video is being
matched against the actual installation.
A failure does not result in a system
halt.
The video buffers (B0000h and
B8000h) are tested with a pattern test
and a rolling ones test. Failure will
result in a beep code but not a system
halt.
Until the video installation is confirmed,
any calls to INT 10h Function 0 (set
mode) will be prefaced with the
diagnostic code. There is no expected
failure from this.