to help isolate a power subsystem problem, follow these steps:

    step 1 check whether the power supply led labeled good is on or the led labeled fail is on. (on the dc multi-input power supply, the leds are labeled input 1, 2, or 3 or output fail.)

    step 2 if the led labeled good is off or if the led labeled fail is on, take the following steps:

    1 ensure that the power supply is flush with the back of the chassis.

    2 unplug the power cord, loosen and reinstall the power supply, tighten the captive installation screws, and then plug in the power cord.

    step 3 if the led labeled good remains off, there might be a problem with the ac source or the power cable. connect the power cord to another power source if one is available.

    step 4 if the led labeled good fails to light after you connect the power supply to a new power source, replace the power cord.

    if this unit has more than one power cord, repeat step 1 through step 4 for each power input.

    step 5 if the led labeled good still fails to light when the switch is connected to a different power source with a new power cord, the power supply is probably faulty. replace the power supply.

    step 6 if the led labeled fan ok fails to light when the switch is connected to a power source with a known good power cord, there is a malfunction in the fan that cools the power supply. replace the power supply.

    step 7 if a second power supply is available, install it in the second power supply bay.

    step 8 check that the led labeled good is on for the additional power supply. check that the led labeled fail is off.

    step 9 if the leds are not on, repeat the previous procedure to troubleshoot the second power supply.

    if you are unable to resolve the problem, or if you determine that either a power supply or backplane connector is faulty, contact the cisco technical assistance center (tac) for instructions.