Digital Equipment DEC 3000 Series Service Information page 175

Power-Up LED Error Codes,
CXT LED
Codes
If the system enters the console program, then run the MEMORY
diagnostics and interpret the error information using

The SHOW ERROR command

Diagnostic information (Chapter 4)
LED Code Description
20 Machine Check
21 CELL Fill mem with test pattern data
22 CELL Forward Rd/Compare/Complement/Wr
23 CELL Reverse Rd/Compare/Complement/Wr
24 ADDR Fill mem with addresses as data
25 ADDR Read/Compare data = address
26-2a Reserved
2b LLSC load-locked/store-conditional tests
2c BCTP Bcache Tag Parity detection
2d ECC detection
2e Reserved
2f Clear memory to zeros
The following LED codes represent continued power-up testing. If
an error occurs during this testing sequence, the system displays
a hexadecimal code plus FRU and error code information on the
screen.
If the system enters the console program, then run the CXT
diagnostics and interpret the error information using

SHOW ERROR command

Diagnostic information (Chapter 4)

Diagnostic error messages (Appendix C)
If the unit does not enter the console program (>>> prompt
displayed on monitor or DD code displayed on the LEDs), then
use Tables 6–6 and 6–7 to isolate the failed FRU.
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6–7