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Table 3-2. LED Indicators and Error Codes for Test 1 and Phase 1 of Test 2
Error Code
*
Bank of
Bank of
4 LEOs
8 LEOs
1111
11111111
0001
XXXXXXXX
0010
XXXXXXXX
0011
XXXXXXXX
0100
XXXXXXXX
0101
XXXXXXXX
0110
XXXXXXXX
0111
XXXXXXXX
1000
XXXXXXXX
1001
XXXXXXXX
1010
XXXXXXXX
1011
XXXXXXXX
1100
XXXXXXXX
1101
XXXXXXXX
1110
XXXXXXXX
1111
OOOOXXXX
Meaning
Initial power-on condition. All LEOs are turned on when PON signal is low. Incorrect
indication may be caused by microcode load or execution problem, an A990 board
failure, EPROM failure, or power system failure.
Failure caused by bad EPROM or bad A990 board.
Base set fatal error (also known as machine check error) has occurred after VCP was
started. See LED indications below for fatal base set error codes.
Failure caused by bad jumper board.
Failure caused by bad memory frontplane connector.
Failure caused by bad memory array card.
Failure caused by bad time-of-day clock chip or bad A990 board.
Failure caused by bad A990 board (possibly caused by a bad processor ASIC Chip).
Failure caused by bad A990 board (possibly caused by a bad cache ASIC Chip).
Failure caused by bad A990 board.
Failure caused by bad A990 board.
Failure caused by bad A990 board.
Failure caused by bad A990 board.
Failure caused by bad A990 board.
Failure caused by bad A990 board.
Failure caused by bad EPROM or A990 board (board failure possibly caused by a bad
processor ASIC Chip).
The following LED indications are caused by fatal base set errors after the VCP program has started:
0010
00000001
00000010
00000100
00001000
00010000
Control store parity error. May have been caused by bad hardware.
Microcode stack overflow or underflow. May have been caused by an error in the base
set microcode.
Zap counter interrupt. May have been caused by an error in the base set microcode.
Two consecutive micro-interrupts. May have been caused by bad hardware.
A micro-interrupt occurred, but the micro-interrupt register did not contain a known
error pattern. May have been caused by bad hardware.
The following are Test 2 Phase 1 LED indications:
0000
11111110
11111100
11111000
11110000
Microcoded self-test (Test 1) passed but first memory fetch failed. Bad A990 board.
Basic instruction test failed. Bad A990 board.
Boot memory access failed. Bad EPROM or A990 board.
TBG test failed. Bad A990 board.
*
1
=
lit LED; 0
=
unlit LED; X
=
don't care
3-6
Service
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