system board failure, PSU or PSU cabling failure [SOLVED]

[PerfectChaos7]

I'm on a modified dell t1650 (500W EA-500 Bronze, GTX 960, 8 GB DDR3 RAM, 1 TB HDD + 2 SSDs).
After shutting down my computer, I tried to turn on my computer only to find the amber LED blinking in the power button. It is a series of two beeps, a pause, and another two beeps. According to the owner's manual, this means "system board failure, PSU or PSU cabling failure". I did the paperclip test on my PSU, and it's working just fine. Do I need to buy a new motherboard? The ethernet cable LED is working just fine, I'm not sure if that's an indicator or not.

 

[Lutfij]

I did the paperclip test on my PSU, and it's working just fine.

The paperclip test only verify's that the unit can power up but it does not indicate how much power the unit can provide at a certain load level.

You may need to bread board your entire system while also borrowing a branded reliable PSU of similar wattage (550W) and see if the system is operable. If you're under warranty, please proceed with an RMA. Please follow up with this guide.

Is this what your internals look like

?
If so you can go ahead with a matx board of your choice in your preferred budget but please so note that not all CPU sockets are the same.

The ethernet port will light up if it's receiving minimum power to the port and if there is a wire connected to it from your ISP/router/internet connectivity device.

 

[PerfectChaos7]

Okay, now what I'm about to say may seem very very odd at first, but I think I've found the solution.
The problem was not my PSU at all, I'm not sure why my Dell thought so, but the problem was something to do with my motherboard.

Shortly after posting this earlier this year, I took apart my entire PC and rebuilt it. And what do you know, it booted just fine! After plugging in all the parts (including my ethernet cable, monitor DVI, usb keyboard and mouse, usb headphones, and my usb hub), it gave the same fatal blinking LED. weird huh? So I used process of elimination and found that the issue was with my USB hub. Whaaat?

So it looks like my system was failing to boot if I used the external power on my USB hub, and only worked after I started using the system power through the USB. My PC booted flawlessly for months, but it was quite annoying because I used the hub to charge my headset while I wasn't using it, so I had to find another solution.

I can't remember how or why (I think it was because I bought a new drawing tablet, and had the issue again), but near the end of June, I decided to solve the issue, and all I decided to update my BIOS using the software from DELL's website. Now the USB hub is able to boot with external power.

TL;DR, the issue wasn't with my PSU, my BIOS was just having trouble booting with the USB hub on external power. the fix was to update BIOS.

 

[Lutfij]

^ It's for this exact reason why we ask for full system's specs and the peripherals you're using. In the process of troubleshooting one such suggestion is to make sure your BIOS is up to date followed by removing the add-ons until you're left with bare essentials for booting up (bread-boarding).

Glad to learn that you managed to solve the issue