GE LPS-O Instruction Manual page 205

9 SERVICING
A critical failure denotes total interruption of protection. When a failure occurs on one of the boards (excluding
the power supply), the critical alarm contact opens and the status LED turns red. Remove and re-apply DC
power to display the fail message. If the LPS-O successfully restarts, the status LED turns green.
If the failure still exists, the status LED will be red and the critical alarm contact will be open. A FAIL message
may also be on the display. The Fail message indicates the nature of the critical failure. It remains on the dis-
play until a key is pressed or until the LPS-O restarts successfully with no self-test failures. See Section 9.3.7:
SERVICE SYSTEM STATUS FAILURES on page 9–6 for the list of mnemonic failure codes and their mean-
ings.
NOTE: The Information–LPS Status command can be used to display all the current failures.
Use Section 9.3.7: SERVICE SYSTEM STATUS FAILURES on page 9–6 or the Information Status command
to isolate the cause of the failure. Then refer to Figure 3–4: CIRCUIT BOARD LOCATIONS on page 3–4 to
determine which board contains the defective logic module. When the suspected board is found, power down
the LPS-O and replace the board.
The proper sequence for replacing a board is as follows:
1. Remove the four thumbscrews holding the plastic cover in place and lay aside with the plastic cover.
2. Turn the power switch off on the front panel.
3. Remove DC power from the LPS-O.
WARNING: Completely power down the relay by disconnecting the control DC power
and by removing all voltage inputs to the rear terminals prior to opening the unit. Dan-
gerous or lethal voltages may be present inside the unit even if the power switch is OFF!
4. Remove the four 3/16" hex nuts at the four corners of the front panel and carefully remove the front panel.
5. Disconnect the power and the ribbon cables from the front panel and lay the panel aside.
6. Remove the two ribbon cables and power cables from the front of the PC boards and lay aside.
7. Remove the PC board that connects the other PC board and lay aside in an anti-static bag.
8. Remove the defective PC board and place into an anti-static bag for storage or shipment.
9. Remove the replacement board from its anti-static container and insert into the LPS-O case.
10. Reinstall the connecting PC board.
11. Reinstall the ON/OFF switch cable and the two ribbon cables.
12. Reconnect the LCD display ribbon cable and the RESET/METERING cable to the front panel with the four
3/16" hex nuts.
13. Restore DC power to the LPS-O.
14. Turn on the front panel power switch.
15. Reinstall the plastic cover with the four thumbscrews.
If the FAIL message is gone, then the unit has been successfully repaired. If the message has changed, it is
possible that another board requires replacement.
GE Power Management LPS-O Line Protection System
9.3 TROUBLESHOOTING
9.3.3 SERVICING A CRITICAL FAILURE
9.3.4 LOCATING THE DEFECTIVE BOARD
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