View original (French)

The computer won't turn on, just a blinking LED on the motherboard.

studioku -  
jeannets Posted messages 28463 Registration date   Status Contributor Last intervention   -
Hello everyone,

my computer has crashed, I can't turn it on anymore, there's just the LED of the power button on the motherboard (Gigabyte Z170x UDS TH) that blinks when the power supply is connected, no other reaction when pressing the power button.
I changed the power supply, it's the same thing.
I only left the processor and nothing else on the motherboard before trying different things, first making contact between the pins of the power jumper to see if there was a problem with the front switch, nothing.
I tried all of this:

There are 3 methods, depending on the severity of the BIOS corruption

Method 1: Power on and power off
Shut off the power supply (by turning off the main switch). Wait for 10 seconds.
Press and hold the PC Power On button and then turn on the power supply.
Release the PC Power On button once the PC starts.
Shut off the power supply as quickly as possible thereafter.
Turn the power supply back on
Start PC as usual using the Power on button

Method 2: Resetting the BIOS
Shut off the power supply and wait 10 seconds
Press the PC Power on button and PC Reset button all at the same time for about 10 seconds
Release the buttons thereafter and turn on the power supply to start the PC as normal

Method 3: Resetting the CMOS
The mechanical method of method 2 except to apply the jumper or remove the CMOS battery to clear the CMOS settings. This method may require the removal of the board as the jumper might be difficult to locate; the alternative is to remove the CMOS battery and wait for 10-15 seconds for CMOS settings to be cleared

I should note that I made contact between the jumper pins for all 3 examples above, because even connected to the motherboard jumpers, the power button LED on the case does not light up...

Nothing very hot or burnt smell, nor apparently any leaking capacitors.

Any other leads?

Thanks!

7 answers

  1.
    jeannets Posted messages 28463 Registration date   Status Contributor Last intervention   Ambassador 6 618
     
    Hello,

    if your CMOS battery is low, it should be 3 volts; at 2.8V it’s already too low, you need to change it.

    You say: “if there was a problem with the front switch, nothing.” What does that mean..? Nothing abnormal or nothing found...?
    Normally, with a strap between green and black, the power supply should turn on... and you can hear its fan...
    -- Disconnect the 24-pin connector from the motherboard; and put your strap between green and black... the power supply should start.

    Has this PC ever worked for you...?

    +++ Minimum PC Startup +++

    The motherboard is equipped with a BIOS... you received a manual with the motherboard... It explains how to access the BIOS (Generally, it’s the Delete key immediately upon powering on and before the logo ends) you need to be quick...

    For now, I’m not talking about Windows... the goal is to get the PC to work, not Windows, that will come later.

    So if accessing the BIOS yields nothing, you need to disconnect everything from your setup... leaving only the motherboard (with its processor and one RAM stick) connected to its power supply and the case's power button... And the wired keyboard, that’s all...
    No graphics card, no hard drive or SSD, no CD/DVD drive, no monitor.
    Power on the PC while closely watching the keyboard lights... They should light up briefly, maybe all three then one... and then you can play with the Num Lock and/or Caps Lock keys... the lights should change state with each key press...

    If that’s not the case, you need to disassemble everything and go step by step, ensuring the correct connection of each component... don’t get confused with the fans.. the 4 or 8 pin connector above the CPU PWR_CPU...

    Here’s a first checkup to do.
    0
  2. studioku
     
    The contact between the two pins of the power jumper on the motherboard did not result in any change, the PC does not start.

    To access the BIOS, the computer would need to turn on, I will buy a new CMOS battery, maybe the voltage is indeed too low but I have nothing to measure, in any case, it is not completely discharged, the tongue tingles when it is on the battery.

    If you read my post to the end, I performed the operations I describe just with the processor on the motherboard, the same ones before with an additional memory stick, but nothing else.
    0
  3. jeannets Posted messages 28463 Registration date   Status Contributor Last intervention   Ambassador 6 618
     
    Alright... I also said to unplug the power supply from the motherboard with its big connector about 24 pins... plug it into the 220V outlet and then put the jumper on the 24-pin connector between green and black...

    Here, the PC should not start... (read carefully) its power supply is unplugged... it's only the power supply that should start... we should have 5 volts between black and red and 12V between black and yellow on a Molex connector for example... and the power supply fan should be spinning... the power button doesn't light up either.

    It could be broken... but on two power supplies, that’s a strange coincidence...

    No need to copy us the methods 1--2--3 that have already been seen and reviewed on English-speaking sites.
    0
  4. studioku
     
    The power button LED on the motherboard starts blinking when I turn on the power supply, which means the juice is flowing.

    I did the test you mentioned; it worked the first time with the original power supply and then failed afterwards.
    I connected a new power supply, which I will test for good measure, but it didn't yield any better results.
    0
  6. jeannets Posted messages 28463 Registration date   Status Contributor Last intervention   Ambassador 6 618
     
    I admit I don't fully understand your description in the text.

    --- The power LED on the motherboard shouldn't light up since the connector is unplugged... So, what have you done then..?

    -- What I'm talking about is connecting the power supply only and turning it on... You say: "it worked the first time with the original power supply... How long.?... That's good... But it failed afterwards, what's that, is it with the same power supply..?? or another..? one time it works and another time, it doesn't...?

    -- Then you talk about a new power supply that you will test; and it didn't give anything more...??? what should be understood..?? have you tested your new power supply or not..? It didn't give anything more... What does that mean..??

    -- You need to have a working power supply before you can go further... are you able to test the output voltages..? the 5v and the 12v..

    -- Has this PC ever worked for you..? what happened just before this blockage that caused it to fail..?
    0
  7. studioku
     
    We are clearly having difficulty understanding each other, thank you for stepping in to give me a hand Jeannets, but when communication is struggling, it becomes an additional obstacle.
    It's the computer on which I have all my music projects, I feel like I have explained the situation in enough detail.
    0
  8. jeannets Posted messages 28463 Registration date   Status Contributor Last intervention   Ambassador 6 618
     
    So I'm repeating my questions because I'm not in front of your PC.

    --- The power LED on the motherboard can't turn on since the connector is unplugged.

    -- What I'm talking about is just connecting the power supply and turning it on... sometimes it works and sometimes it doesn't...? please elaborate.

    -- Then you mention a new power supply, ??? what should I understand from that..?? have you tested your new power supply or not..?? Nothing more given... What does that mean..?? it's not very likely to have both broken.. or is it something else.

    -- You need to have a functioning power supply before you can go any further... are you able to test the output voltages..?? the 5V and the 12V..

    -- Has this PC ever worked for you..?? what happened just before this blockage that caused it to fail..??

    The follow-up will be after that..
    0