Question Computer sometimes power cycles multiple times before reaching BIOS

[schadley]

I've had this computer for the past 4 years, but I recently started having this issue. I've finally hit the end of my debugging/Google skills. When I turn my computer on, it sometimes power cycles (fans turn on, lights turn on, power supply clicks, then everything turns off) multiple times before reaching the BIOS and displaying something on the screen. I would estimate about 10 seconds on, 3 seconds off. This can happen anywhere from 0 times to taking 15+ minutes in this mode.

Specs of the system:
CPU: i5-6500
Mobo: Gigabyte B150 Phoenix Wifi
Memory: 16 GB generic G.Skill
GPU: Gigabyte 1060 6GB
PSU: Corsair SF450
Case: Fractal Design Node 202

Some of the things I've tried:

• Removing the GPU. I've been testing with just integrated graphics to remove a point of failure. I thought it might be an issue with the PCIe riser in my case, but the same issues occur with the GPU completely disconnected.
• Testing RAM sticks one by one. The system has the same inconsistent behavior with each individual stick as well as both sticks together. I also ran memtest64 after my computer eventually booted with each stick, but found no errors.
• Testing without any RAM sticks at all. Obviously, my computer never booted without RAM. However, it was interesting to see the same issue - powering on for 10 seconds, powering off for 3 seconds - with the RAM removed. It seems that a failure is detected during POST before RAM is tested, but my interpretation could be incorrect.
• Using the CMOS clear jumper and removing the CMOS battery (I did those two things separately). Neither of these made any changes to the overall behavior.

I think this helps to narrow down what the issues may be:

• GPU almost definitely isn't an issue.
• RAM probably isn't an issue, since removing RAM didn't change behavior and both sticks seem fine.
• I know the power cycling could be caused by the CPU overheating or an issue with the CPU fan. But, the computer sometimes does boot and run correctly without any noticeable errors, so that seems unlikely in this case.
• I haven't tested my SSD at all, but I doubt it's at fault for the same reason as the CPU/CPU fan.
• PSU could be a problem.
• Motherboard could definitely be the issue, probably the most likely cause at this point.

I appreciate anyone who's made it this far. I'd love to hear any ideas for what could be causing this, or what tests I can do to diagnose the issue. I am trying to get my hands on a different PSU to determine whether that is the problem, which is probably a good next step.

 

[rocktalkrock]

It would help if you listed the parts in your system.
You never said if this is a new build or a new problem with an old build that has been working properly.

 

[schadley]

It would help if you listed the parts in your system.
You never said if this is a new build or a new problem with an old build that has been working properly.

Done, ty.

 

[MeanMachine41]

When the system restarts during post cycle and constantly fails, it's often because the interrogation process cannot find a stable set of SPD values to boot the system. I would try manually setting timings and voltage values in Bios. There may be no errors as per Memtest86 however can be caused by a mismatch or confused Bios with the memory controller. List your RAM Part No to check their frequency and that they are listed on the MB QVL.

 

[schadley]

When the system restarts during post cycle and constantly fails, it's often because the interrogation process cannot find a stable set of SPD values to boot the system. I would try manually setting timings and voltage values in Bios. There may be no errors as per Memtest86 however can be caused by a mismatch or confused Bios with the memory controller. List your RAM Part No to check their frequency and that they are listed on the MB QVL.

That's a good idea. I tracked down the RAM I am using which is here: https://www.newegg.com/g-skill-8gb-288-pin-ddr4-sdram/p/N82E16820231959
The QVL is pretty short, but doesn't include my specific model: https://download.gigabyte.com/FileList/Memory/mb_memory_ga-b150n-phoenix.pdf

Do you think that would be an issue that showed up after 4 years though?

EDIT: I checked the BIOS, the frequency is correct and the timing is mostly correct (the BIOS is seeing 15-15-15-36 timings instead of 15-15-15-35, but I don't think that would be a problem). It doesn't look like I can change any of the timings on this motherboard either way.

 

[MeanMachine41]

I agree, it's not your RAM if Memtest86 checks reveal no errors and you haven't made any changes in Bios.
Have you tried to flash your Bios to the latest version.?

It could be a failing CMOS battery (CR2032) considering it's four years old and well worth replacing at $4.
Only way to really check the PSU is swap it out with a known working unit of the same or higher Wattage.

Very often issues during post cycle can be identified using a Motherboard speaker for the beep code.?

 

[schadley]

I agree, it's not your RAM if Memtest86 checks reveal no errors and you haven't made any changes in Bios.
Have you tried to flash your Bios to the latest version.?

It could be a failing CMOS battery (CR2032) considering it's four years old and well worth replacing at $4.
Only way to really check the PSU is swap it out with a known working unit of the same or higher Wattage.

Very often issues during post cycle can be identified using a Motherboard speaker for the beep code.?

Both good suggestions, thanks. I tried switching the CMOS battery but no luck, same results as before. I don't have access to another PSU unfortunately, but I will try my best to get that.

I did hook up a speaker to try that out. I get 1 beep on a successful POST, no beeps otherwise which doesn't really help.

 

[MeanMachine41]

And you have the latest Bios?