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T4000 Six-Input DC Power Supply LEDs


The LEDs on the faceplate of each power supply (see Table 1) indicate the status of the power supply. The DC OK, OVERTEMP, and INPUT PRESENT LEDs are located on the faceplate of the power supply. A power supply failure also triggers the red alarm LED on the craft interface.

Table 1 describes the six-input DC power supply LEDs on the faceplate.

Table 1: Power Supply LEDs





INPUT PRESENT—One per input


On steadily

Input is receiving voltage within the required range of –40 V through –72 V.


Input voltage is not present, or the voltage is not within the required range of –40 V through –72 V.

DC OK—One per power supply


On steadily

When input 0 and at least one other input is properly energized and the power switch is ON, this input indicates that the power supply is functioning normally.


Power supply is starting up or is not receiving any input voltage. The power switch on the power supply faceplate or the customer site external circuit breakers might be off. A fault might have occurred.

OVERTEMP—One per power supply


On steadily

Power supply has exceeded the recommended temperature and has been powered off.


The power supply is within the recommended temperature, or the power supply is not receiving any input voltage.