7901 with port’s 5 & 6 stuck on

[Anonymous user]

I have a 7901 with ports 5 & 6 stuck on; you go into management page and turn the ports off, the LEDs cycle off but power still is at the receptacle. Is there anyway of testing to see if it’s a hardware error or getting the relays to cycle?

[BillP]

This sounds like some type of relay weld. Do these get cycled on/off frequently and have high current devices connected? Depending on warranty status, sometimes you may be able to "shake" these loose but it could potentially weld again.

I would say if anything, its definitely a hardware issue.

[Anonymous user]

Right now the ports only had smaller network devices on them, so pretty low power. But, alas I am not the original user, so I can not attest to their usage in the past and I just built up the rack to test some ideas on. I have really never thought about duty cycle on the relays before. Since this hardware is non production and only used testing ideas, is there any issue with ports mostly being off? Basically everything is kept off until we need to build a test environment, it might for be run for the day and turned off at night, it might be run for a few days, it might been off for weeks at a time, or I could spend my day simulating power issues and cycling the equipment on and off.

[BillP · Accepted solution]

No, there is no issue with keeping them off but the relays in the PDU are only designed for XXXXX amount of switches/cycles. I forget what the exact number is but these are definitely not designed to be constantly cycling 24/7.

What you describe is probably what many other users do also (lab environment). I don't think what you're specifically doing personally is causing a problem. Off the top of my head and based on experience, factors leading up to this type of failure include age, number of cycles, current on each outlet, etc or a combination could contribute to this type of failure. Of course, a tiny percentage could always be because the relay was defective from the start which we'd cover under the factory 2 year warranty on the PDU anyway.

Do you think the PDU is under warranty? I could help you determine that by the first six characters of the serial number.