Catalyst 3750G power on issue orange system level leds

[zeroasylum]

Hi All,

I have had something weird happen to my Cisco 3750G poe switch ( I purchased it second hand but it still has 6 months on its warranty from refurbish reseller). So a few weeks ago I powered the switch down as I was installing some new equipment in the rack and when I powered it back on the fan came on full and all the system level led came on orange. I thought it was possibly dead. I unplugged it and plugged it back in again and it started up fine.

Last night I had to power the switch down again. Then when I powered it back up the same thing happened. So I unplugged it waited about thirty seconds and plugged it back in again. Same issue all orange system level leds.

I tried it again once more and here’s the weird thing. So the plug was a little stiff going into the power socket on the PDU and I noticed that the switch started its normal boot sequence with the power plug half inserted. I pulled it out and put it in again and it gave me the orange lights. I then did the half way trick and then slowly pushed the power plug all of the way in and it booted fine.

So does anyone have any idea what could be wrong? Could it be the switch power supply.  It is up at the moment and running fine. I am going to change the power cable later tonight just encase that is the issue.

Many thanks

Zeroasylum

[Adam Pawlowski]

Of those I've dealt with most of the ones that had a bad power supply were weeded out back in the 2006-2009 era. The PS either just failed or the caps exploded. But, that was obvious because it turned off.

These are also known to have bad flash memory or memory failures - if the switch isn't booting I'd just have it replaced if your vendor can supply it.

[zeroasylum]

Thank you for the reply. I suspected either caps on psu or some other psu fault. I did read about the bad flash as well.

I am going to pull it tonight and put in a spare I have in a lab setup and get the vendor to replace it. At least I was able to get it to boot again to pull the config from it.

Many thanks

Zeroasylum

[Leo Laohoo]

What is the manufactured date of the switch?  It could be affected by the faulty memory component.

[zeroasylum]

Thank you for the reply. The switch is a WS-C3750G-24PS-S. From memory it is a 2009 manufacture date but can confirm this later I know it is end of life but is still fully functional (well until this problem) . Would it still be replaced even if I have bought it as a refurbished unit from a reseller.

Thanks

Zeroasylum

[Leo Laohoo]

If this was made 2009 then I can guarantee the memory is the culprit.

[zeroasylum]

I have checked and manufacture date is August 03 2009. So is my next step to contact Cisco or the reseller who sold it to me.

Many thanks

Zeroasylum

[Adam Pawlowski]

Hi,



The end of hardware support date was back in January so I believe the limited warranty ended with that.



If your reseller has replacements I would go that route.



If these can be had cheaply enough that there are spares, and you can keep them in continuous operation (ups, don't upgrade IOS and reload) they seem to work reliably. I have many that do and continue to do so. For whatever reason, probably due to invested cost, many resellers seem to keep these in the several hundred USD price range and they aren't worth it given the instability. If you can get them cheap enough and protect them, and keep a spare on hand, they probably are serviceable for most uses.



Cisco is not the only vendor that had suffered from bad flash componentry in things of this era.



Adam

[zeroasylum]

Hi Adam

Thank you for the reply. I have contacted my reseller and have an RMA for a return and hopefully either a repair or replacement. You are correct they may be older hardware but are still good for everyday use on smaller sites with less critical data or in a lab setup for testing.

I am curious as I have 2 more of these switches (which are now out of warranty) which are working fine but the just encase do you know the issue with the ram chips is it the chips themselves that degrade or the solder joints.

The reason I ask is I have repaired similar issues in the past on graphics cards and main boards to do with dram chips with brittle solder joints due to heat cool action and a lack of led in the solder due to newer regulations in solder production requiring a re-flow and therefore have access to all the tools necessary to do these repairs.

Thanks

Zeroasylum

[Adam Pawlowski]

Information on this issue I believe is here:



https://www.cisco.com/c/en/us/about/supplier-sustainability/memory.html



More specifically:



https://www.cisco.com/c/en/us/support/docs/field-notices/637/fn63745.html



The componentry itself is bad I don't believe it is solder or anything you can do to repair it. I don't have enough working knowledge of the components specifically to say if it were a DRAM chip or something you could replace yourself or not.