Gigabyte AB350 Gaming 3 red CPU LED

[dominik0801]

Hello!

Today I got a motherboard stated in the title. It was sold as a not working one, known problems were: few smd components missing from the back, red CPU LED always on, no post.

The reason I bought this motherboard is because I have the exact same one in my PC, so I knew I could check what components are missing from the back.
It was a few filtering caps and one SMD resistor. The resistor seemed to be a 22ohm one, and I put a new one in the right place.

I know smd caps are not really necessary, so I was about to left all down, however I put 4 of the 7 missing on, just to be sure the board is more stable.

After trying to boot the motherboard, it failed. Same symptoms: no post, RGB lights only flicker once (then go black), and the CPU RED LED is constantly on.

Since I know this could be a BIOS problem, I flashed both chips with the version I have on my board.
No change.

I didn't find any short on the board, nor bad traces (I might be wrong ofc).
Voltages seem to be present, as far as I measured.

One weird behaviour, that could help someone: by pressing the power button for 4 secs, the board should shut down. However, this board does nothing.

(Note: There's another flash chip on the board, marked as "ECAU2", but it's empty. Unfortunately I can't check the one on my own board, since it's still under warranty, and I don't want to desolder it.)

Any ideas?

[dominik0801]

Re: Gigabyte AB350 Gaming 3 red CPU LED

I'm usually the one, that makes a forum post with questions that leave everyone speechless, but then I figure out something. Unfortunately this wasn't the case today..

So I woke up with some extra energy, and I said I don't care about my board's warranty, lets desolder the BIOS and the other flash chip, read their data, and flash the bad board's chips.

The "ECAU2" flash chip was not empty on my own board, it actually contained lots of data for the IT8792 and IT8686 controllers. Remember that the bad board had an empty chip, so I was confident this would fix something.

At this point the motherboard should have functioned, like my own does..
but no, still the same problem.

For the last idea, I tried a RAM from my own PC, but to be honest, every part has been tested, and it's definitely a motherboard problem.

So right now I can only think about a bad chipset or CPU socket maybe.

Edit: checked socket, its fine.

[dominik0801]

Re: Gigabyte AB350 Gaming 3 red CPU LED

Sorry for triple posting, I fixed the board.

Took mine out of my PC case again, and this time I focused on the top side of the board. Saw a resistor missing at the chipset. Soldered one on the board. Now it posts and boots like a new.

[RJARRRPCGP]

Re: Gigabyte AB350 Gaming 3 red CPU LED

Hello!

Today I got a motherboard stated in the title. It was sold as a not working one, known problems were: few smd components missing from the back

Sounds like it was abused by a computer noob! That's why I feared getting a Titan X used! For me: Ripped off SMD component(s)=Done deal!=DNF!

[dominik0801]

Re: Gigabyte AB350 Gaming 3 red CPU LED

Yeah, I like challenges, so I took it.
Btw, since I browsed the whole internet, but I couldn't find the IT87xx and IT86xx EC flash chip content anywhere, I can provide the contents of mine, if someone needs it.

Basically, if you brick your board's EC firmware with the known faulty updater tool, you can restore your board. Feel free to ask me.