check for system messages related to the power supply, and refer to the system message guide for your software release. you may need to add a power supply or upgrade to a larger one for your current configuration or verify that the switches are set properly. connect a terminal to the console port, and look for any of the following system messages:

    c4k_chassis-2-inlinepoweroff

    c4k_chassis-2-insufficientpowerdetected

    c4k_chassis-2-insufficientpowershutdown

    c4k_chassis-3-insufficientpower

    c4k_chassis-3-insufficientpowersuppliesdetected

    c4k_chassis-3-mixinpowerdetected

    c4k_iosmodportman-3-unknownpowersupply

    c4k_iosmodportman-4-inlinepowerovermax

    c4k_iosmodportman-4-inlinepowersupplybad

    c4k_iosmodportman-4-powersupplybad

    c4k_iosmodportman-4-powersupplyfanbad

    c4k_supervisor-3-powersupplystatusreadfailed

    c4k_supervisor-3-powersupplyseepromreadfailed

    c4k_supervisor-3-powersupplyseeprominvalid

    c4k_supervisor-4-inlinevoltageoutofrange

    you may also use the show environment status powersupply, show module all,and show power commands to monitor ps status, load, and activity.

    the 1400 w dc multi-input supply can not be used with other power supply types, but other power supplies in this product line work with the other types during an upgrade. if you mix power supplies in a catalyst 4500 series chassis, the switch detects the type of power supply in power supply bay 1 (ps1) and ignores the power supply in power supply bay 2 (ps2) while issuing system messages and showing the power supply in bay 2 as in the err-disable state in the output of the show power command. when the power supply in bay 1 is removed,the switch recognizes the power supply in bay 2, and you may then put a new matching power supply in bay 1. both supplies should now resume normal function.