Technical data

4-42 Fault Isolation
Test LEDs are mounted vertically on the system unit’s front upper right-hand corner.
The front panel must be opened to see all of them.
Table 4-7. General Failure Code Descriptions (Upper Two Bits Fail Indicators)
Upper 2 Bits Fail Indicator LED Code and Failure Description
State indications only.
LEDs indicate power-up state.
Required device missing or
data acknowledge failure.
LEDs indicate device.
Failing device.
LEDs indicate device.
Special codes.
(Special case highest priority codes)
LEDs
never
accessed.
LEDs
failed
to
acknowledge
data.
CPU
board
timer
failed or
missing.
A
B
C
D
E
F
G
H
A
B
C
D
E
F
G
H
A
B
C
D
E
F
G
H
A
B
C
D
E
F
G
H