[c-nsp] WS-C2970G-24TS as access switches

Mike mike-cisconsplist at tiedyenetworks.com
Thu Dec 29 16:09:33 EST 2011

On 12/29/2011 12:28 AM, Jay Hennigan wrote:
> On 12/28/11 11:02 AM, Mike wrote:
>> I was using these for exactly the same reasons stated above. This year,
>> I have had three seperate instances where the switch had to lose power
>> (move, re-work pwr arrangements, etc), and all three times the PSU
>> apparently gave up the ghost and refused to power back up. Nothing
>> 'happened' funny power wise, not zapped or otherwise mistreated in any
>> way. I think these units were of a vintage vulnerable to the bad
>> chineese capacitor problem and I think whatever cap in the psu just went
>> fizzle while it was operating, which would let the units continue
>> running but once it lost power, would prevent a successful full power on
>> start up.
> This is a very common failure mode with some types of switching power
> supplies.  It is typically a resistor and not a capacitor.  We saw a lot
> of it with the power bricks supplied with Fujitsu DSL modems a few years
> ago.  It's real fun when there's a widespread power outage and customers
> all over town are down once power is restored.

In this case with the 2970's, it's definately a capacitor. I don't have 
my photos now but it was the same cap all 3 times that bulged out and 
made it obvious it was the problem.

> These power supplies are commodity items from Chinese manufacturers that
> are used in a variety of gear, not just Cisco switches.  You can often
> Google the part number on the power supply brick itself and find
> replacements.

I had that idea too but for the 2970 all I was able to find were branded 
replacements costing 3x the cost of the used rps675...


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