Question I want to know if my Motherboard is faulty. VGA LED on MOBO is on. I checked other parts as well.

Jul 12, 2021
So here is how it all started. Last week I left my house, and I left my computer on, when I came back there was no video signal and I noticed that the VGA led status indicator on my Motherboard was on. This status led indicates that there is something not working properly with the graphics output/device on the machine. I would turn it off and then on, and the CPU LED would turn on and off to check if all was good, and then the DRAM led would turn on and then off as well to check that part and then it would get stuck in the VGA led on and I would get no post.

  • At this point I decided to start diagnosing my computer, first I disconnected every USB device and tried turning it on, VGA LED would turn on regardless.
  • Then I tried to put only one (of my 2 ram sticks) to see if that was the problem, I also swapped them, VGA led turned on regardless.
  • I then tried putting my GPU into another PCIE slot, then again, stuck on the VGA led on.
  • I tried using another GPU (an old one), stuck on the VGA led on again.
  • After that, I tried removing my HDD, and turning, stuck on the VGA led again.
  • Then I tried removing my nvme ssd out of the computer, and then again no post, with the same VGA led on.
At this point I decided to lend a friend’s computer with a motherboard with the same socket for my CPU. All of the devices I had tested with my own PC worked properly, so thankfully my GPU was fine, my ssd and hdd was fine, and my ram was fine. Then I decided to try my CPU on my friend’s motherboard, I could not make it post with my friend’s motherboard, but the motherboard BIOS was not up to date to support my CPU so that is why it did not work (probably, i did not realize this until later, at that point i thought my CPU was not working).

After that I (stupidly) decided to try my friend’s CPU on my motherboard, I turned on my motherboard to try it, and the LED’s started cycling between CPU, DRAM and then VGA (like 3 times, this lasted for 30 seconds), and then I realized that if my mobo is faulty I could kill my friend’s CPU thinking about what happened to my CPU. So I didn’t wait for it to post since I was afraid, so I turned off the PC and removed my friend’s CPU and put it back in his motherboard.

At that point my diagnosis was that the faulty components could be either my Motherboard or my CPU or both.

I decided to also measure my Power Supply voltages to see if there was anything wrong with the voltages, and apparently all of its voltages were perfect. I did not measure current nor wattage consumption (since I do not have the tools for that), but with the measurements I took I do not think that is the problem.

I then realized my friend’s motherboard’s BIOS was not updated, so I decided to try my CPU on a cousin’s motherboard with the BIOS updated to support my CPU, when I tried my CPU on that friend’s MOBO (which is similar to mine) it got stuck on the same VGA LED after cycling through the other LED’s, this to me told me that my CPU was definitely faulty. Do you guys think my diagnosis on the cpu is correct? I already sent the RMA to use the 3 year warranty.

Now I want to know if I also have to replace my Motherboard, since I am guessing that it could be either good or faulty, since those LED’s work fine (I say this because my cousin’s compatible bios motherboard i tried using did the same thing with those LED’s), and while I did not want to see if my motherboard would post with my friend’s CPU because I did not want to damage it, it did CYCLE through the LED’s as if it was initializing the CPU on my motherboard for those 30 seconds, I say this because when I put my cousin’s CPU on his motherboard back on, it did take a good 1:15 mins to post and these LED’s were cycling (cpu-ram-vga-cpu-ram-led) and then it booted and those turned off.

I also want to point out (cause it could be important), a thunder struck around 1 km away from my house, and there was a blackout after it hit. My computer worked fine once the lights came back on for 4 days after that, don’t really think it was this, but it could be, I do have a voltage spike suppressor.

If you have questions, I will answer all of them, and if you think it could have been the PSU by all means, tell me.

Here are my PC specs (I have been using this PC for 1 year and 3 months) :
  • Motherboard Aorus Pro Wifi b450
  • CPU Ryzen 7 3700x 8 cores
  • 16 Gb RAM Corsair Vengeance LPX ddr4 3600MHz
  • GPU Nvidia RTX 2070 Gigabyte 8 Gb de ddr6
  • SSD XPG Gammix s11 de 1tb 3,000-3,500 mb/s
  • HITACHI 2TB HDD 7k rpm
  • Gabinete NZXT H510
  • PSU Corsair CX850M Semi Modular
My friend’s PC specs:
  • Ryzen 5 2600
  • GPU Radeon RX 580
  • 16 Gb RAM Corsair Vengeance LPX ddr4 3200MHz
  • Motherboard asus tuf b450m-plus gaming
My cousin’s PC specs:
  • Ryzen 5 2600
  • GPU Radeon RX 580
  • 16 Gb RAM (don’t know what brand)
  • Motherboard ROG STRIX b450-F gaming