General Description Of Failure Codes; Sample Boot Rom Self-Test Leds With Key - HP 400 Series Servicing Manual

The highest priority failure also sets off the beeper. The lower 7 bits of the LED value
are sounded off, most significant bit first, one second per bit, with a zero represented
by a low tone and a one represented by a high tone.
If the failure was a Boot ROM checksum error, the following message is displayed:
CONTINUE AT OWN RISK (Press RETURN To Continue)
Once this message has been printed, the RETURN key must be pressed to continue to
the boot scanner. The probability is fairly low that the error adversely affects the user,
but if it does, it could be catastrophic.
For all other failures, the following message is displayed:
WAITING 1 MINUTE (Press RETURN To Abort Wait)
The Boot ROM times out after approximately one minute and then continues into the
boot scanner. This allows time for the monitor or terminal to warm up and for the user
to read the error messages. These failures are usually non-fatal so, in an unattended
mode, the Boot ROM still boots the first operating system it finds. Pushing the
RETURN key terminates the beeping error code and aborts the one minute wait. Push-
ing the RETURN key also makes the system unit go into attended mode. This means
that the Boot ROM displays all operating systems found and does not boot a system
until one is chosen and entered by the user.
4.9.4

General Description of Failure Codes

Table 4-7 and Table 4-8 show the general meaning of error codes. LED patterns are
represented by a black rectangle for on and a white rectangle for off. A grey rectangle
indicates the LED in that position is on or off, depending on the binary code used to
represent the device or failure type. Use the key that accompanies the sample display
shown in Figure 4-15 to determine LED on/off values.
Figure 4-15. Sample Boot ROM Self-Test LEDs with Key
Fault Isolation 4-41