HP 400 Series Servicing Manual page 115

Table 4-9. System Unit LED Failure Codes (Cont.)
LEDs State or Failure
A
Failure:
B
ROM system.
C
D
E
Replace ROM
F
system.
G
H
A
Not enough memory
B
C to load operating
D
system.
E
F
Add more memory.
G
H
A
Failure:
B
C HP-IB board.
D
E
Replace HP-IB
F
board.
G
H
A
Failure:
B
C Video board
D
bit-map circuit.
E
F
Replace video board.
G
H
LEDs State or Failure
A
Failure:
B
Boot error.
C
D
E
Replace CPU
F
board.
G
H
A
Failure:
B
4 MS timer.
C
D
E
Replace CPU
F
board.
G
H
A
Failure:
B
DMA circuit.
C
D
E
Replace CPU
F
board.
G
H
A
Failure: DIO-I Interface
B
C at select code identified
D
by five lowest LEDs.
E
F
Replace board that has
G
the failed interface.
H
LEDs State or Failure
A
Failure:
B
Operating system tried
C
D
to load at too high of a
E
memory address.
F
Try again or replace CPU
G
or emulator board.
H
A
Failure:
B
C HP-HIL circuit.
D
E
Replace CPU
F
board.
G
H
A
Failure:
B
C High-resolution
D
video board font
E
ROM.
F
G
Replace video board.
H
A
Failure: DIO-II Interface
B
C
at select code identified
D
by five lowest LEDs.
E
F
Replace board that has
G
the failed interface.
H
Fault Isolation 4-45