Supermicro server can't turn on after I disconnect IEC power cord cable without turning off the main

Discussion in 'Chassis and Enclosures' started by touchring, May 5, 2019.

  1. touchring

    touchring New Member

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    Hi,

    I'm not able to turn on my server after shutting down Windows and then disconnect the power cable from the IEC socket on the Power Supply unit. There's no burnt smell but heard some cracking sounds when I remove the cable. I tried changing to another power cable but to no avail. I did this a couple times in the past without any issue, and I remembered doing this to PCs multiple times without breaking any of them, so I'm quite surprised this happened.

    Has anyone experienced something similar and what's the solution? Grateful for any advice. :)

    Here's some info on the Supermicro and PSU.

    Supermicro Chassis - SC504-203B | 1U | Chassis | Products | Super Micro Computer, Inc.
    Power supply - PWS-203-1H - https://store.supermicro.com/media/wysiwyg/productspecs/PWS-203-1H/PWS-203-1H_quick_spec.pdf

    Note: I don't have hardware experience.

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  2. BoredSysadmin

    BoredSysadmin Active Member

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    Have you tried to plug back the power cable? I heard that servers usually work better with power cable connected :rolleyes:
     
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  3. touchring

    touchring New Member

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    Yes, I plugged back the power cable but it won't turn on after that. I've tried changing to another power cable but it didn't help. Let me explained what actually happened and the sequence of events.

    I had a server (Server A) connected to the power cable (and power socket) and decided to change to another server (let's call this Server B). Instead of switching off the mains, I just shutdown windows on Server A, unplugged Server A and plug in Server B (while the power cable is still connected to the mains).

    After that, both Server A and Server B won't turn on. Note: Both were working previously. It sounds silly but this is actually what happened.
     
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  4. kapone

    kapone Well-Known Member

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    Check your circuit breaker?
     
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  5. pc-tecky

    pc-tecky Member

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    @BoredSysadmin - horrible :confused: and shamefully hilarious! :D :rolleyes:
    Just as bad as asking if the power in the neighborhood is out. o_O :rolleyes:

    Disconnecting power from the wall or the back of the computer is virtually the same. No burnt/fried electronics smell (which is very distinctive) is good news. Crackling noise, in this case, can happen when starting/stopping power on motors (fans not switched/turned off), light switches (as they wear out - and not so good), or an obscure/unresolved power drain (should not be an issue here).

    Straight down to basics with electricity, test with a [table] lamp, a radio, or a fan - something that illuminates, makes noise, or moves. Are the other outlets on the same wall, or in that room, or in nearby rooms working? (Common for outlets in the same room and adjoining rooms to be wired on the same circuit.) Check the mains power circuit breaker panel for a tripped circuit breaker as @kapone stated. Check for a tripped GFI outlet (upstream) - near kitchens and bathrooms (were water may be present).
    Perhaps try using another power cord?!? (Maybe a faulty cord from excessive strain? Maybe faulty wiring in the cord?) Let us know when you resolve the issue.
     
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  6. touchring

    touchring New Member

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    f
    Thanks. Do you mean the electric circuit breaker in my home or if there's a circuit breaker in the server itself?

    Here's the tests I did, and the result:

    1. Connected SM Server A to Power socket 1 using Power cable 1 and switched on the mains - Failed.
    2. Connected SM Server A to Power socket 1 using Power cable 2 (located in another room) and switched on the mains - Failed.
    3. Connected LED monitor to Power socket 1 and switched on the mains - Succeeded. LED monitor turns on.
    4. Connected SM Server A to Power socket 2 using Power cable 1 and switched on the mains - Failed.

    I repeated the tests with SM Server B and same result.

    I also tried the following:
    1. Remove CMOS battery, put back again.
    2. Disconnecting the power supply from mains, wait 1 day and try again.

    I Googled a suggestion to repeatedly disconnect and connect the power supply - have not tried that yet.
     
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  7. dswartz

    dswartz Active Member

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    Do you have a spare ATX PS to test? You don't need to actually put it in server A, just plug the two power cables into the motherboard. I'm wondering if pulling the cable caused a power surge of some kind and fried something on the motherboard? Shouldn't have, but who knows? Why server B isn't working either is a mystery...
     
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  8. touchring

    touchring New Member

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    Ok, I just returned from the SM distributor office. Guess what happened?

    The service guy plugged in Server A and it booted. I'm completely puzzled. Then he plugged in Server B and there was a BANG. He jerked and quickly left the room. I noticed that he was wearing rubber safety boots. I didn't notice his expression but he came back later with a PSU and plugged into Server B motherboard and booted up Windows - phew, so only Server B PSU blew, the motherboard appears to be fine. Server B is down as they don't have spare PSU in stock.

    I went back home and found a power cable connected to a mini-PC, and managed to boot up Server A! This means that my 2 power cables were fused. It could be that Server B fused both my power cables or the spare power cable was fused to begin with. I changed the 5A fuse on the original power cable and booted up Server A.

    Here's a photo of the UK style power plug I use. The red piece of plastic is the fuse holder.

    [​IMG]

    In the end, this is still a mystery to me. It could be that Server B PSU was faulty and it "fried" my power cable. It could also be that pulling the cable fried both Server B and the power cable. The spare power cable was then fried by Server B when I tested it with Server B.

    Nonetheless the technician claimed that it's not possible to fry an SM PSU by pulling the power cable. But I'm not going to take the risk again. Always turn off the mains before pulling the power cable.
     
    #8
  9. Scott Laird

    Scott Laird Active Member

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    You do realize that the UK is pretty much the only place in the world where that's possible, right? Most places don't put switches on individual power receptacles, yet somehow all of our electronics survive. ;-)
     
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  10. gregsachs

    gregsachs Active Member

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    Also most places don't have fuses in individual power cords...
     
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