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New Member

6509 Power Supply Output Failure

I have a 6509 chassis w/1 Sup720 and dual 3000W power supplies. When I power it on it runs for about 3-5 minutes and the power supplies shutdown. The red "Output Failure" light comes on. They are connected to 110V/20Amp circuits. These are the same circuits that were used with a previous set of power supplies (lower wattage). I removed everything from the chassis except for the fan tray and the sup module to reduce the power demand. Same result. Thoughts?


Re: 6509 Power Supply Output Failure

To resolve power supply issue, perform these steps:

1) Determine if the show system command output shows the any of the power supplies status as faulty.

2) Inspect the power supplies. Make sure that there is power applied to both units.

3) Reseat the power supply.

4) Try a different circuit or swap power cords.

Note: If the status is still red, or the show system command shows a status of faulty, it is a power supply failure.

5) Remove and replace the power supply.

For more information, refer to the document

Power Management for Catalyst 6000 Series Switches

New Member

Re: 6509 Power Supply Output Failure


Did you upgrade an existing chassis with a sup720? What is the fan type in this chassis? Is it a E chassis or older style that requires a high speed fan tray? Fan tray should state fan tray 2 on outside of fan tray (vertically). For Sup720's the system will shut off after 5 minutes if the fan tray is not a high speed fan tray.

Go here:

New Member

Re: 6509 Power Supply Output Failure

This is what I think is wrong. I got a similar response from TAC and have ordered a new fan tray. I hope to have it in a day or so and will post my results.

Thanks for the help.

New Member

Re: 6509 Power Supply Output Failure


Want to test? Get into ROMMON and set this variable:


The system will remain up regardless of type of fan.

USE WITH CAUTION: I wouldn't recommend leaving the system running like this if your switch is not being properly cooled.