No console output, all lights on Cisco 3750G (WS-C3750G-24TS-S) on at power-on.

[Sam Brynes]

I bought a Cisco WS-C3750G-24TS-S a little while ago on Craigslist. I powered it on, tested it, and everything seemed ok...

... until 2 months ago, that is. I unplugged the power cord from the switch and moved it to a different spot in the rack.

I powered on the switch, and all the lights on the left (SYST, RPS, MASTR, STAT, DUPLX, SPEED, and STACK) were all lit up. None of the port LEDs were on. I waited for an hour, but I couldn't get any output from the console. Some people are saying that means that the switch has failed POST (I found this out later on).

I turned off the switch, thinking that it died, and that I would probably have to order another one. But the next day, when I tried it again, the SYST LED was blinking, and I got console output, and it booted okay to my surprise.

I did some research, and there are a few pages out there saying that many of the 1.5U Cisco 3750G models like mine were manufactured using cheap capacitors that only lasted around 5 years or so (see http://www.bitplumber.net/2009/03/cisco-3750-delayed-power-on/).

I opened up my switch and there didn't seem to be any leaky capacitors, although I'm not sure what the white rubbery substance is on the tan PCB (the power supply board). Does anyone else see any capacitor problems from the pictures (attached)?

Is there a tool that I can use to test all the capacitors on the PCB without unsoldering them? I don't have any experience soldering anything.

I am wondering if a leaky capacitor on the power supply could cause a POST failure, or if the leaky capacitor would have to be on the main board (not the power supply) for POST to fail?

I like Cisco gigabit switches, and it seems like the Cisco 3750 is one of the most popular ones out there, but I'm hesitant on just buying a replacement one if I know that all the capacitors on these models are known to be faulty. Once the switch powers on, I never have any problems. It's only when I plug in the power after it's been recently powered on.

[markwilliams]

10 month old topic I know but google brought me here.  I also have the same issue so I was searching for a solution.  Capacitor plague seems a reasonable suggestion so im going to look at my own board.

In respect to yours, if you look on picture 3381 the bottom right capacitor has blown (the top is definitely bulging and you WILL be able to feel that if you run your finger over it).  They don't always "leak" but that one has blown for certain.  I am quite used to changing capacitors on motherboards (and washing machines, and TVs) so i'll give mine a go; when I open up my switch i'll check the same capacitor - that capacitor on your picture is a different brand to the others too.  If mine is the same issue I will photograph and update your thread for the sake of consistency.

[markwilliams]

no blown caps on mine.  swapped PSU with a known good 3750 (psu in the known good was a different psu with better metal shielding) and it worked so my PSU is dead.  Those I can get off ebay so that will sort me out.