PC reboots repeatedly

[cmy008157602e2]

Like that, a few seconds after the VGA light of EZ debug LED comes on,
the PC reboots repeatedly in a loop,
with nothing on the screen.
(no beep sound)

1. 1. I’ve tried reseating the RAM, and even tested with just one stick in slot 2 — same result.
2. 
   
3. 2. If I remove the RAM completely, the DRAM light stays on and I get a beep sound, with the system staying powered on.
4. 
   
5. 3. If I unplug the GPU’s 8-pin PCIe power cable and boot, the VGA light stays on and I get a beep sound, with the system staying powered on.
6. 
   
7. 4. I also tried shorting the JBAT1 jumper to reset CMOS — no change.

Motherboard: MSI PRO B660M-A DDR4
CPU: intel i5-12400F
GPU: RTX 3060 Ti

No CPU or RAM overclocking.
It ran fine for two years, then suddenly this happened.

Is this definitely a GPU issue?
Or could it be a power supply problem?

 

[cmy008157602e2]

Also, the very first boot after reseating RAM, this shows up.
(CPU or Memory Changed !!!
Please enter Setup to conf igure your system.
Press F1 to run setup.
Press F2 to load default values and continue.)

No matter what I press, it just reboots immediately and goes back to the loop without showing that message anymore.

 

[citay]

Is this definitely a GPU issue?
Or could it be a power supply problem?

Well, what's your PSU model, and how old is it? But those two things should definitely be ruled out. The GPU, you can just borrow a different one, no older than 2019 if possible. Now you also see why it's usually better not to get a CPU model ending in -F: It's good to have an iGPU for troubleshooting, for bridging the time between two GPUs, and so on.

The PSU, again, try to borrow a different one and connect it on-the-fly using its own cables. It has to be known good, not too old, and of decent quality. Maybe, if we find out that your current PSU is particularly old and/or bad, you might want to buy a new one outright.

 

[cmy008157602e2]

Well, what's your PSU model, and how old is it? But those two things should definitely be ruled out. The GPU, you can just borrow a different one, no older than 2019 if possible. Now you also see why it's usually better not to get a CPU model ending in -F: It's good to have an iGPU for troubleshooting, for bridging the time between two GPUs, and so on.

The PSU, again, try to borrow a different one and connect it on-the-fly using its own cables. It has to be known good, not too old, and of decent quality. Maybe, if we find out that your current PSU is particularly old and/or bad, you might want to buy a new one outright.

Thank you so much!!

Yeah I found out cpu with -F is not good the hard way.
Same with no-wifi version of motherboard.

This is my PSU.
700W with 80plus bronze.
I've been using this for 2.5 years, like every other parts.

I should try ruling out GPU or PSU with my friend's PC.

But is there any chance that the motherboard itself is the problem?

 

[citay]

Mmmh, this is a no-name low-end PSU, 80 PLUS Bronze "EU" (230V only), so, worse than the normal Bronze rating. The warranty is reassuringly high, but it's not exactly what i'd use for that kind of system with a nicer GPU, you want an 80PLUS Gold unit that ticks all the boxes already. I'm not saying this is definitely the cause, but there's enough reason to test with another known good PSU for sure.

But is there any chance that the motherboard itself is the problem?

Well, it's possible, but you never start from there, because it's the most difficult to test. You start by leaving out what can be left out (for example the GPU if had an iGPU, or any drives), and trying with a borrowed part when it can't be fully left out, in an effort to narrow it down further.

And then, for example if your friend's GPU makes your PC work again, you can test with your GPU in his PC too. But if your GPU works in his PC as well, then that cannot be the full explanation, then it could still be that the PSU has somehow deteriorated enough to cause problems in combination with your GPU, or something else.

 

[cmy008157602e2]

Mmmh, this is a no-name low-end PSU, 80 PLUS Bronze "EU" (230V only), so, worse than the normal Bronze rating. The warranty is reassuringly high, but it's not exactly what i'd use for that kind of system with a nicer GPU, you want an 80PLUS Gold unit that ticks all the boxes already. I'm not saying this is definitely the cause, but there's enough reason to test with another known good PSU for sure.



Well, it's possible, but you never start from there, because it's the most difficult to test. You start by leaving out what can be left out (for example the GPU if had an iGPU, or any drives), and trying with a borrowed part when it can't be fully left out, in an effort to narrow it down further.

And then, for example if your friend's GPU makes your PC work again, you can test with your GPU in his PC too. But if your GPU works in his PC as well, then that cannot be the full explanation, then it could still be that the PSU has somehow deteriorated enough to cause problems in combination with your GPU, or something else.

Okay I've tried these:

1. I put my GPU into another PC.
-> it worked ️

2. I put another GPU into my PC.
-> it didn't work. Same rebooting issue

3. I tried my PSU with another PC
-> I was unable to check with the screen but at least the system stayed on ️

4. I tried other PSUs(500W, 600W) with my PC
-> it didn't work. Same issue

5. I reset CMOS by shorting jbat1 and taking off the battery for 5 minutes
-> Same issue


Now I'm 90% sure that the problem is in the motherboard.
Am I right? Or is there anything else I could check before sending my motherboard for a repair?

 

[Alan J T]

Now I'm 90% sure that the problem is in the motherboard.
Am I right? Or is there anything else I could check before sending my motherboard for a repair?

I would agree, but please note the cost of repairs may exceed the cost of a new Board

But you may still have some warranty left

 

[citay]

2. I put another GPU into my PC.
-> it didn't work. Same rebooting issue

What exact GPU? This is important. If it's too old of a model, it can cause the VGA LED for a different reason.

4. I tried other PSUs(500W, 600W) with my PC
-> it didn't work. Same issue

Which models? 500W, 600W says nothing, they could be absolutely terrible models or way too old, which makes them unsuitable for getting a second opinion.