Beep Codes - DEC DECpc 433 Service Manual

Troubleshooting
Beep Codes
If
POST finds
an
error condition and cannot display
a
message, the system
board speakd emits a series of beeps to ir.dicate the error condition. It also
writes a value into
J/O
port
SOH
for both fatal and not-fatal errors. No value
is written to
1/0
port
80H
for intelligent graphics controller error conditions.
Beep codes are either fatal and not-fatal. Fatal errors prevent the system from
booting. Non-fatal errors allow the system to attempt a boot. For example, if
the speaker emits
a 2-1-4
beep code
(a
burst of
two
beeps, a single beep, and a
burst of four beeps), bit three of the first
64 KB
of
DRAM
failed its test Table
2-3
lists the beep codes for fatal errors and the values written to
J/0
port 80H.
Table 2-4 lists the beep codes for non-fatal errors and the values written to 110
port80H.
Beep codes for the intelligent graphics controller are different in that
only
long and short beeps are emitted. It is the number of ea1:h that identifies the
error condition. Table 2-5 lists the intelligent graphics controller beep codes.
DECpc 433 Workstation Service Guide
2-11