Question Debug LED are on

[netsonic]

The computer was built about 7 yrs ago and it has been running well until yesterday.

There was nothing on the screen. Then I rebooted several times, i noticed the cpu debug led was on for less than 1 sec, then off. Then the vga debug led was on for a few sec, then off. At last the boot debug led was on for a few sec, then off. Sometimes dram debug led was on for secs then off.

Today I tested the gpu on anther computer, it worked. Only the dram debug led was on. I also tried the "MemOk" button on the Asus mb, but it didn't help.

CPU：i7-8700k
CPU cooler：Noctua NH-U14S
MB：ASUS Prime Z370-A
Ram：Crucial Ballistix Sport LT 32GB Kit (8GBx4) DDR4 2666 MT/s PC4-21300
GPU: Gigabytes GV-N970IXOC-4GD
SSD: 4
Hdd: 2 SATA
PS: Antec Earthwatts 500W
CASE: Antec P180

 

[In2Photos]

The debug LEDs should turn on during the POST process, that is normal for them to turn on then turn off as each part passes POST. What is happening after POST? Do any lights stay on? When you tried the GPU in another PC did you use the same monitor and cable as the other computer? If not, try using a different monitor/cable and report back.

 

[netsonic]

On the first day, the Leds turned on then turned off. But in the follosing days, the Dram Led keeps turning on.
I unpluged all the 4 RAM sticks and pluged one RAM stick which works on another PC, the Dram Led kept turning on.

 

[In2Photos]

Check the CMOS battery and make sure it's good. Then clear the CMOS. If that doesn't work unplug everything but the basics. Just power and plug your monitor into the motherboard output, remove the GPU too. Unplug all USB, front panel connectors and everything.

 

[netsonic]

I replaced the old CMOS battery on the first day, Do I still need to clear the CMOS?

 

[In2Photos]

I replaced the old CMOS battery on the first day, Do I still need to clear the CMOS?

Has anything else changed in the system lately? Clearing CMOS just resets all BIOS settings back to default which makes the PC the most likely to boot.

 

[netsonic]

Nothing has changed recently. On the fist day of failure, I replaced the CMOS battery, that's all.

 

[BoomerD]

Per the manual, a single stick of RAM should be placed in slot A2 which is the one farthest from the CPU. Try that...maybe try all your sticks of RAM in that slot.

It's not impossible that your board has crapped the bed...it happens...it is 7 years old...

 

[netsonic]

I tried every RAM stick in the slot A2, but none works

 

[In2Photos]

I tried every RAM stick in the slot A2, but none works

Try booting with just the essentials as I mentioned here.

Check the CMOS battery and make sure it's good. Then clear the CMOS. If that doesn't work unplug everything but the basics. Just power and plug your monitor into the motherboard output, remove the GPU too. Unplug all USB, front panel connectors and everything.

If it still doesn't boot I'd try reseating the CPU in the socket. You could also try another power supply.

 

[William Gaatjes]

I replaced the old CMOS battery on the first day, Do I still need to clear the CMOS?

Indeed you do. General information, so bare with me and be forgiving : When the cmos battery is dead, all the bios settings can be scrambled since these are stored in what is called volatile memory and the battery voltage is too low for specific digital zeros and digitasl ones to be read. So you always have to clear the cmos after replacing the battery but only afterwards when you make photos of all the settings in the bios. As a fall back measure. And of course NO OVERCLOCKING while debugging the complete system !
Generally speaking when you clear the bios, default settings should be loaded by the bios itself. But sometimes you need to help the bios by clearing the cmos with a jumper or a switch. After clearing the cmos place the jumper or switch to the normal position. See BIOS manual of the mainboard.