Question Yellow Light on Asus ROG STRIX Z490-A even though RAM should be fine

[Hakairo]

Here is the built I just ordered and put together: https://pcpartpicker.com/list/ytYQk6

So I had some issues in the beginning which came down to a problem in a cable of the power supply. Anyways due to this troubleshooting I tested the built outside of the case with only the following plugged:

• CPU
• CPU Cooler
• both RAM Sticks in A2 and B2
• M2 SSD
• Power Button of the case
• Power for Motherboard and CPU (obviously)

This test worked after switching the cables of the PSU. By it worked I mean that I got a video signal from the motherboard, listing the hardware and suggesting me to go into the BIOS since it was my first boot. This is where I ended the test, since I thought everything works now.

So I put the Motherboard back in the case, connected basically the same stuff and additionally the whole case stuff (fans, power button, HDD LED) and I wanted to check again if it still works (why should it stop working suddenly, right?)

But the test failed, no video signal and the LED of the Motherboard keeps glowing yellow (to be precise it goes red for half a second and then to yellow). Based on the Manual this indicates a problem with the DRAM, even though this was not the case a few minutes earlier outside of the case. The light keeps on forever, the fans spin all the time, so it does not shut down.

So here is everything I did after that:

• Take it out of the case (because this was basically the biggest change)
• Take out the RAM completely - results in the same behavior but I assume this makes sense since it checks for RAM, which is missing
• Put in each stick individually in each Slot one after the other and both at the same time in every possible constellation
• Reset CMOS

And thats currently it. Since I got a video signal once, which showed the processor I have correctly, I would assume that none of the parts are faulty in general, but at the same time something has to be a problem.

EDIT: I made just a few more tests for fun and I had the following scenario:
I put one of the stick in B2 and it worked, I again got a video signal. So I took it out, put the other stick in B2 and it worked.
After that I added the other Stick in A2 so both sticks are in A2 and B2 (which is what I want) and it stopped working.
So I took out the Stick from A2 (So I get the scenario where it worked 2 minutes ago) and it was not working.
I switch the sticks, so the other one is in B2 and now the LED was Red, where it starts, switch to yellow, goes off for a half second, goes red, goes yellow and repeats.
I turned the power off and on and I am stuck at the yellow LED again.

EDIT2: I put both in B1 and B2 and it worked multiple times in a row. Putting one from B1 to A2 gave me the negative result again. I am continue my tests and maybe I just got with B1 and B2.
Anyways I wanna hear Opinions on this strange behavior.

EDIT3: After a lot more testing, B1 and B2 are stable, but as soon as I use A1 or A2 it does not work.
Now I do not know for sure if its the CPU or Motherboard. So I either go with both sticks in B1 and B2 or try to get a new CPU and/or Motherboard to see who is the culprit.

 

[MikeinHouston]

Just ran into a similar problem w same motherboard using an i5. Nothing exotic in it.
When I first powered it on last night, the fans came, but no sign of a post, only the yellow Q-LED indicating a memory problem. Good thing my son was around. I hadn't built a machine in 9 years. He tried various combination of ram, trying the sticks individually.
He then found your message and did find we could get into the bios with one 16GB stick in B2, but the Q-LED would cycle thru red and white. He also found, like you, it would would post with one stick in B1 and one in B2, but not in A2 where the manual said.
I found ASUS had a bios update from July and updated the bios using their clever flashback scheme with a USB stick. Made no difference. Bios showed it recognizing both sticks.
Rechecked the QVL and verified that my ram was on the list.
Corsair Vengeance LPX 32GB (2x16GB) 3200MHz C16 DDR4 DRAM Memory Kit – Black.
After all that I gave up and used the return option on my Amazon order. Had never done that before. Very easy. Should have a replacement board by tonight. Keeping fingers crossed and will report back.
Any changes on your end?

 

[Hakairo]

Just ran into a similar problem w same motherboard using an i5. Nothing exotic in it.
When I first powered it on last night, the fans came, but no sign of a post, only the yellow Q-LED indicating a memory problem. Good thing my son was around. I hadn't built a machine in 9 years. He tried various combination of ram, trying the sticks individually.
He then found your message and did find we could get into the bios with one 16GB stick in B2, but the Q-LED would cycle thru red and white. He also found, like you, it would would post with one stick in B1 and one in B2, but not in A2 where the manual said.
I found ASUS had a bios update from July and updated the bios using their clever flashback scheme with a USB stick. Made no difference. Bios showed it recognizing both sticks.
Rechecked the QVL and verified that my ram was on the list.
Corsair Vengeance LPX 32GB (2x16GB) 3200MHz C16 DDR4 DRAM Memory Kit – Black.
After all that I gave up and used the return option on my Amazon order. Had never done that before. Very easy. Should have a replacement board by tonight. Keeping fingers crossed and will report back.
Any changes on your end?

almost forgot i made this thread. I ordered a new motherboard and it worked perfectly. Sounds like this happens with this board from time to time.

Also I noticed that the new ones passes POST much much quicker than the faulty one.

to be specific I did not order the exact same. I instead ordered a Z490-F. the changes are extremely minimal and high likely are not important for most users. But the F version seems to be a newer revision from what I found out with a re-worked production method.

 

[MikeinHouston]

FWIW, here's my parts list
https://pcpartpicker.com/list/nHXH6R
Already had the hard drives and was going to use those along with spare drives in an unraid build.

 

[MikeinHouston]

Thanks. I did find some similar reports on othe ASUS boards on here. Hoping it was just a fluke. The original board was about all I need since it's only a server that can do some virtual gaming and am not a hard core gamer.
BTW, last build was a silent home server 9 years ago with an i3 and ASUS board. Still running fine.

 

[Alexnotsoyoung]

Just ran into a similar problem w same motherboard using an i5. Nothing exotic in it.
When I first powered it on last night, the fans came, but no sign of a post, only the yellow Q-LED indicating a memory problem. Good thing my son was around. I hadn't built a machine in 9 years. He tried various combination of ram, trying the sticks individually.
He then found your message and did find we could get into the bios with one 16GB stick in B2, but the Q-LED would cycle thru red and white. He also found, like you, it would would post with one stick in B1 and one in B2, but not in A2 where the manual said.
I found ASUS had a bios update from July and updated the bios using their clever flashback scheme with a USB stick. Made no difference. Bios showed it recognizing both sticks.
Rechecked the QVL and verified that my ram was on the list.
Corsair Vengeance LPX 32GB (2x16GB) 3200MHz C16 DDR4 DRAM Memory Kit – Black.
After all that I gave up and used the return option on my Amazon order. Had never done that before. Very easy. Should have a replacement board by tonight. Keeping fingers crossed and will report back.
Any changes on your end?

Please let me know if the new board works properly. Running into this same problem as well. Want to know if I have to replace the board or if there is any other fix. Thank you!

 

[MikeinHouston]

Please let me know if the new board works properly. Running into this same problem as well. Want to know if I have to replace the board or if there is any other fix. Thank you!

The replacement board is supposed to arrive today from Amazon. I do find that impressive.
Since I just had a couple of glasses of wine, even if it arrives immediately, don't think I've get the build reassembled til tomorrow.
Will let you know.

 

[MikeinHouston]

Please let me know if the new board works properly. Running into this same problem as well. Want to know if I have to replace the board or if there is any other fix. Thank you!

Just following up. I didn't get the replacement board until Tuesday and managed to get the machine back together last night.
It works!
Got a little worried when booting and it cycled thru red and white LED's and I saw what looked like the Q-LED was yellow indicating a memory problem but my son pointed out there was another LED and the one we were seeing was not the one indicating a ram problem. I don't think the QLED is system is the best for old guys with bad sight and some colorblindness.
In any case, it booted into the bios and showed 32GB ram.
I had downloaded an install of Windows 10 from here and created a USB install. Get Windows 10 install I rebooted with the USB key inserted and the machine recognized the USB and offered to install Windows which I did. You can install and run it for 90 days without a license and longer if you don't mind not being able to personalize it and have a nag in the lower right.
My only problem now is wanting to install Unraid which requires booting from a USB stick. Doesn't matter what I set in the Bios, it keeps booting into Windows. Damned modern bios

 

[Jefferthefrog]

I too have had the yellow light issue on my brand new Asus Rog Strix Z490-f. This is part of an upgrade with some new RAM and a new Core i5 Unlocked 10600k cpu.

On initial start up, it all worked fine and I installed windows 10, etc. Left the room for 20 mins and came back to a dead computer.

I've got 2 sticks of 8 GB Corsair vengeance DDR4 2666 Mhz. After a bit of testing, my PC boots fine with one stick installed, in any location (A1, B1, A2 or B2). Installing the other 8GB stick however - either next to the one that works or on its own - means I get the yellow DRAM LED show on the mobo. No display, mouse or keyboard activity.

I'm hoping this is a stick of faulty RAM issue rather than a dodgy mobo or cpu but would appreciate any feedback/advice.

 

[MikeinHouston]

I too have had the yellow light issue on my brand new Asus Rog Strix Z490-f. This is part of an upgrade with some new RAM and a new Core i5 Unlocked 10600k cpu.

On initial start up, it all worked fine and I installed windows 10, etc. Left the room for 20 mins and came back to a dead computer.

I've got 2 sticks of 8 GB Corsair vengeance DDR4 2666 Mhz. After a bit of testing, my PC boots fine with one stick installed, in any location (A1, B1, A2 or B2). Installing the other 8GB stick however - either next to the one that works or on its own - means I get the yellow DRAM LED show on the mobo. No display, mouse or keyboard activity.

I'm hoping this is a stick of faulty RAM issue rather than a dodgy mobo or cpu but would appreciate any feedback/advice.

Sorry, can't provide any help on your problem. After Amazon replaced the board and I got it reassembled, mine has worked without a glitch. I installed Unraid on it and am trying to figure that out. The dashboard says it's been up for three days. There haven't been any other hardware problems.
Good luck

 

[cunlij]

Hi all. I had a similar problem - this time with an Asus Z490-A.

After much exasperation, I now have a working computer but only by putting the DDR4 in DIMM_B1 and DIMM_B2. Put a single memory module (or extra DRAM) in DIMM_A1 or DIMM_A2 and the dreaded yellow light comes on, there is no POST, there is no display and I have a crippled computer.

I am using a Core i5 10400 (to be upgraded later) with Corsair Vengeance 3600 Mhz 2 x 8 GB DDR4.

Interestingly, I had a similar problem with a Prime H410-A motherboard (this will later become my NAS) but, of course, there are no QLEDs on that to tell me where the problem is. It just refused - point blank - to POST. That is why I was forced into splashing out on the Z490 before I had intended to. Imagine my exasperation when that did not work to start with.

Is it the combination that's doing it? Could it be that two different Prime motherboards have a similar problem? Is it a BIOS problem (favoured explanation)? I will try contacting Asus but that could be problematic at the moment.

Meantime, do I return the Z490 as faulty?

These are mostly meant to be rhetorical questions but I won't complain to anyone who attempts a reply.

 

[MikeinHouston]

Hi all. I had a similar problem - this time with an Asus Z490-A.

After much exasperation, I now have a working computer but only by putting the DDR4 in DIMM_B1 and DIMM_B2. Put a single memory module (or extra DRAM) in DIMM_A1 or DIMM_A2 and the dreaded yellow light comes on, there is no POST, there is no display and I have a crippled computer.

I am using a Core i5 10400 (to be upgraded later) with Corsair Vengeance 3600 Mhz 2 x 8 GB DDR4.

Interestingly, I had a similar problem with a Prime H410-A motherboard (this will later become my NAS) but, of course, there are no QLEDs on that to tell me where the problem is. It just refused - point blank - to POST. That is why I was forced into splashing out on the Z490 before I had intended to. Imagine my exasperation when that did not work to start with.

Is it the combination that's doing it? Could it be that two different Prime motherboards have a similar problem? Is it a BIOS problem (favoured explanation)? I will try contacting Asus but that could be problematic at the moment.

Meantime, do I return the Z490 as faulty?

These are mostly meant to be rhetorical questions but I won't complain to anyone who attempts a reply.

My motherboard was still within the return window. Reported problem to Amazon and I had a new board within 2 days along with a return label. Has worked fine since. It think Asus must have put out a few bad boards.
Reminds me that I received a Z490 Prime a couple of weeks ago to use in upgrading my 6 year old server. Been too busy to look at it. Need to try it to make sure it doesn't have the same problem.

 

[cunlij]

Well !! I ended up with advice from ASUS technical that it was probably "not on the list RAM" that was causing the problem (misread a D for a B). So I got some "is on the list RAM". So now I have spent ANOTHER £70 but ....... I would have got there eventually. Same result, solid yellow RAM light. So another mail to ASUS tech help got the response "send the motherboard back". The replacement arrived today (£25 cheaper !!). So, tonight I thought this will only be an hour and I duly changed the board. I am pleased to say that all 32 GB of RAM is now working. All four slots are full. Overkill, probably for my use but it's good to know it has plenty of overhead. An hour and a half would have been enough but my dual boot Samsung PCIe SSD lost its MBR and I spent many (happy I must admit) hours chasing the problem down until I was able to write this. It's a motherboard fault !!!