Diagnostic LED Codes
Overview
The system uses the eight LEDs on the control panel to indicate
the currently executing test. When power is turned on, all the
LEDs come on (LED code is FF(h)), and then display different
codes as the devices are tested.
The LED codes are divided into two fields.
The left-most four LEDs represent the device number.
The right-most four LEDs represent a substate that the
device test is currently in. LED codes E0h - FFh are reserved
for the console.
Translating
Error Codes
The eight LEDs on the lights and switches board can be
translated into two hexadecimal or binary digits in the form:
X X X X
Y Y Y Y
X X X X is the device number (binary) currently under test.
Use Table 5–4 to match the code from the LEDs to a device.
Y Y Y Y is the subtest at which the diagnostic hung.
The LEDs can be used for troubleshooting when the console device
is inoperable.
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