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Cisco 3750 Delayed Power On

March 31st, 2009 Leave a comment Go to comments

Last week I un-racked a Cisco 3750 (WS-C3750G-24TS) from our datacenter and brought it over to our office.  This device had been running reliably at the datacenter for over a year.  When I went to power it back up at the office, the device acted DOA.  No lights, no fans, nothing.

I tested the power cord on another 3750 switch to make sure the power was good and it worked fine.  So I plugged it back into the dead 3750 and tried re-seating the cord, etc, to no avail.  At this point I picked up the phone and called Cisco to get an RMA issued.  About half way through my conversation with the call-taker, I looked down on my desk and realized the switch had booted.  I continued with the Cisco case as the last thing I needed was an intermittent switch.

I then tried un-plugging the switch and plugging it back in several times, and it would boot every time.  Thinking it might be a capacitor charge issue, I un-plugged it while I went to lunch, and then re-connected it when I got back and it took several minutes again to power on.  I have since reproduced this a third time, in which it took over five minutes to boot!  I actually have it on video just in case I need to prove it to Cisco.

This was such a weird failure mechanism that I figured I should share in the hopes that someone else might find it a useful data point.

-Eric

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  1. binary617
    November 19th, 2009 at 13:38 | #1
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    I’ve seen this happen as well on a few WS-C3750G-24TS.

  2. Paul L.
    July 29th, 2011 at 20:36 | #2
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    I came across a 3750 (ws-c3750-24ts-s) and got a real good deal on it. Before buying it, I powered it up and logged into the console port and plugged my Ethernet into every port to see it come up and down.

    It worked perfectly!

    I came home and fell asleep on the couch playing with my new switch while watching my training videos. Here’s where things went south…

    I woke up in the morning to no response in putty and looked at the switch and noticed no lights on. I could hear the fan still turning.

    I pulled the plug and powered it back up. All the lights on the left come on, they all go out, then the top light (SYST) blinks twice, then everything is dark. I can still hear the fan running.

    I left it unplugged all day hoping that when I returned this evening that it would power up properly. However, no such luck.

    1. Do you think it’s a power supply or a board issue?

    2. If I were to purchase a smartnet contract on it, would I then have it covered under a hardware warranty?

    Thanks in advance for your time and consideration.

    Your friend in Virginia,
    Paul

  3. Ciscom
    September 25th, 2011 at 11:35 | #3
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    Hi Guys, I’m from Puerto Rico and had the same problem at the company I work for.

    Symptoms: C3750G-24TS Reliable switches that once unplugged they died. Some of them were DOA other turned on but as a “brick”.

    NOTE: This DOES NOT affect the WS-C3750G-24TS-1u and later generations switches. Only the “thick ones” (1.5 rack unit).

    Problem: Bad Capacitors.

    Reason: A batch of these switches were manufactured with capacitors which lifespan is 50,000 hours. So if you happened to have one of these switches manufactured on 2004…Do the match. On 2009 when this forum was last updated, 5 years has passed or 50,000 hours. Capacitors failed and so your switch.

    This not a defect thing. It’s just the type of capacitors they used to manufactured these switches doesn’t last as much as 5 years. I’m not sure if Cisco is aware of this, but they will not recognize this either.

    I lost at my company 11 switches. I replaced the capacitors on the few I needed and brought them back to life, for at least 5 more years…hehehe.

    I encourage you guys an whoever read this to open your switch and see for yourselves the bloated capacitors, of course if you doesn’t have a SMARTNET, it wouldn’t be smart to open your device though.

    Now, how to solve this?? Get them to an electronic repair store and have those capacitors replaced. Have them check the Power Supply too. Or you can do it for your selves, if you know your electronics basics will suffice.

    NOTE: You won’t find this info on the Internet. I think I’m the first one to really take the time and post it.

  4. Ciscom
    September 25th, 2011 at 11:39 | #4
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    Ciscom :
    Hi Guys, I’m from Puerto Rico and had the same problem at the company I work for.
    Symptoms: C3750G-24TS Reliable switches that once unplugged they died. Some of them were DOA other turned on but as a “brick”.
    NOTE: This DOES NOT affect the WS-C3750G-24TS-1u and later generations switches. Only the “thick ones” (1.5 rack unit).
    Problem: Bad Capacitors.

    I wanted to say that if you have SMARTNET, open a ticket witch Cisco. Never do this type of troubleshooting if your devices are in Warranty, otherwise you will VOID it.

    Reason: A batch of these switches were manufactured with capacitors which lifespan is 50,000 hours. So if you happened to have one of these switches manufactured on 2004…Do the match. On 2009 when this forum was last updated, 5 years has passed or 50,000 hours. Capacitors failed and so your switch.
    This not a defect thing. It’s just the type of capacitors they used to manufactured these switches doesn’t last as much as 5 years. I’m not sure if Cisco is aware of this, but they will not recognize this either.
    I lost at my company 11 switches. I replaced the capacitors on the few I needed and brought them back to life, for at least 5 more years…hehehe.
    I encourage you guys an whoever read this to open your switch and see for yourselves the bloated capacitors, of course if you doesn’t have a SMARTNET, it wouldn’t be smart to open your device though.
    Now, how to solve this?? Get them to an electronic repair store and have those capacitors replaced. Have them check the Power Supply too. Or you can do it for your selves, if you know your electronics basics will suffice.
    NOTE: You won’t find this info on the Internet. I think I’m the first one to really take the time and post it.

  5. eprosenx
    September 25th, 2011 at 11:40 | #5
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    Thanks for posting!

    This sounds exactly like what the issue was…

    I did not bother opening it up since I had SmartNet on it and could simply get Cisco to ship me a new one. 😉

    There was a spate of bad capacitors a while back (having to do with bad gel in them). I suspect this is related…

    -Eric

  6. Ciscom
    September 25th, 2011 at 11:41 | #6
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    Ciscom :

    Ciscom :

    I encourage you guys an whoever read this to open your switch and see for yourselves the bloated capacitors, of course if you doesn’t have a SMARTNET, it wouldn’t be smart to open your device though.

    What I wanted to say, IF you have a SMARTNET, DO NOT DO THIS…Open a ticket with Cisco, otherwise you will be VOIDING your Warranty/Contract.

    Thanks

  7. Ciscom
    September 25th, 2011 at 11:44 | #7
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    Two Years late but finally I post this…hehehehe.

    I hope this will help others like me, who had these damaged switches on their Home Labs. That is the purpose of this info.

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