Question Is my new CPU defective ?

[kataProkroustes]

I'm trying to build a new system with all new parts. This is my second system build. The last one was ten years ago and everything came together without any problems.

This time I'm trying to figure out if I have a bad CPU and would appreciate advice. I don't have a PSU tester or another socket AM5 motherboard to test the CPU with. Upon visual inspection, the CPU and socket appear clean and intact.

Here's a list of relevant parts:

• Motherboard: Gigabyte B650 AORUS ELITE AX V2 AM5 LGA 1718 AMD B650 ATX
• CPU: AMD Ryzen 7 7700 3.6 GHz 8-Core Processor (100-100000592BOX)
• Storage: Samsung 980 Pro 1 TB M.2-2280 PCIe 4.0 X4 NVME Solid State Drive (MZV8P1T0B/AM) (2 each; installed in slots M2A_CPU & M2C_SB)
• Storage: Seagate BarraCuda 4TB Internal Hard Drive HDD – 3.5 Inch Sata 6 Gb/s 5400 RPM
• Memory: G.Skill Trident Z5 Neo 64 GB (2 x 32 GB) DDR5-6000 CL30 Memory (F5-6000J3040G32GX2-TZ5N) (installed in slots DDR5_A2 & DDR5_B2)
• Power Supply: SeaSonic Prime Fanless PX-500 500 W 80+ Platinum Certified Fully Modular Fanless ATX Power Supply
• Case: Fractal Design Define R5 ATX Mid Tower Case

After assembly, there is power to the case, switches/LEDs, case and CPU fans, and motherboard. However, the computer does not POST/boot; there is no audio or video output.

The CPU status LED on the motherboard comes on but all the other status lights on the motherboard are off. According to Gigabyte: "If the CPU/DRAM/VGA LED is on, that means the corresponding device is not working normally ..." (To clarify, there are separate status LEDs for CPU, DRAM, VGA, & BOOT-OS).

I have verified that the CPU is correctly oriented and installed properly and the CPU power cables are properly installed. I also tried moving the CPU power cables to different sockets on the PSU. Nothing solves the apparent CPU issue.

I think the problem is most likely with the CPU but I wanted to see if there were any other troubleshooting tips I should know about before requesting warranty service from AMD. I have also requested tech support from Gigabyte.

 

[Lutfij]

Welcome to the forums, newcomer!

How are you cooling the processor? Might want to reinspect the CPU's socket for any bent of broken pins and when reseating the CPU, place the processor in as flat as possible, devoid of an angle. Have you tried building outside of the case(i.e breadboarding)? Try with one stick of ram.

I don't see any mention of a discrete GPU, did you forget it or did you not get one for this build?

Moved thread from CPUs section to Systems section.

 

[kataProkroustes]

Welcome to the forums, newcomer!

How are you cooling the processor? Might want to reinspect the CPU's socket for any bent of broken pins and when reseating the CPU, place the processor in as flat as possible, devoid of an angle. Have you tried building outside of the case(i.e breadboarding)? Try with one stick of ram.

I don't see any mention of a discrete GPU, did you forget it or did you not get one for this build?

Moved thread from CPUs section to Systems section.

Thanks for responding. The AMD Wraith Prism cooler supports air or water. I'm using just air--it's a 65W processor. In any case, I haven't run it for any length of time because it fails to POST/boot.

I will re-inspect the socket. I was very careful about placing the CPU in flat.

I have not tried breadboarding. I've never done that before and I'm not sure why I would do that. Would you be willing to elaborate?

The CPU, it's actually an APU, has two graphics cores and the motherboard has onboard graphics. So, I don't have a separate graphics card. My current build doesn't have one either.

 

[ohio_buckeye]

Breadboarding is where you pull the board from the case. When I’ve done it I put the board onto the motherboard box, hook up power, ram and gpu as well as the cooler. To start it up, take a flat head screwdriver and touch the power pins on the motherboard.

The reason to consider doing it is you take the case out of the equation. You can have strange things happen if you have a standoff shorting on the back of the motherboard for example. So it just lets you get a very basic setup to where you know whether or not things are working or not. If so then you can start adding things back in.

 

[kataProkroustes]

Later today, I'm going to try using Q-Flash Plus to update the BIOS. Apparently, some folks have reported failure to POST on Gigabyte Aorus mboards when the BIOS hasn't been updated.

 

[kataProkroustes]

Breadboarding is where you pull the board from the case. When I’ve done it I put the board onto the motherboard box, hook up power, ram and gpu as well as the cooler. To start it up, take a flat head screwdriver and touch the power pins on the motherboard.

The reason to consider doing it is you take the case out of the equation. You can have strange things happen if you have a standoff shorting on the back of the motherboard for example. So it just lets you get a very basic setup to where you know whether or not things are working or not. If so then you can start adding things back in.

Thanks for the explanation. I might try that if updating the BIOS fails to resolve the issue.

 

[kataProkroustes]

Later today, I'm going to try using Q-Flash Plus to update the BIOS. Apparently, some folks have reported failure to POST on Gigabyte Aorus mboards when the BIOS hasn't been updated.

So, I updated to BIOS ver. F33 today using Q-Flash Plus. The flash drive and Q-Flash Plus lights blinked for about six minutes and then stopped.

Then I powered down using the PSU switch and re-started. The CPU LED alone stills comes on and the system still does not POST. In other words, nothing has changed with the BIOS update.

 

[kataProkroustes]

I don't have a PSU tester but I do have an Amprobe AM-510 multimeter and yesterday it occurred to me to use it to see if the PSU is sending power through the CPU cable.

Today, I disconnected the ATX_12V1 and ATX_12V CPU cables. Using the VDC settings, the multimeter shows zero voltage from the cables when connected to the PSU while it is turned on. When I checked the cables for continuity they are fine.

This would seem to indicate the PSU is not providing power to the CPU. However, according to Seasonic, "The operation of power supply is a 'pull' technology, which means that the unit only provides the power as demanded by the mainboard and the system components." Would that also explain why I get zero voltage from the CPU cables?

Is there another way to check the CPU power output from the PSU with a multimeter or do I need to buy a PSU tester? I know I can swap the new PSUs into my current machine as a test but I'd rather not do that just yet.

Update: So, if I turn on not just the PSU but also the system then I get 12 VDC from both of the CPU cables. Therefore, it seems that the PSU is not the problem.

 

[kataProkroustes]

Breadboarding is where you pull the board from the case. When I’ve done it I put the board onto the motherboard box, hook up power, ram and gpu as well as the cooler. To start it up, take a flat head screwdriver and touch the power pins on the motherboard.

The reason to consider doing it is you take the case out of the equation. You can have strange things happen if you have a standoff shorting on the back of the motherboard for example. So it just lets you get a very basic setup to where you know whether or not things are working or not. If so then you can start adding things back in.

So, I checked the system by breadboarding. The CPU status LED comes on for less than a second on startup and then the DRAM status LED comes on and stays on. I checked with no DRAM modules in the slots and then checked with both modules separately in slot A2 ( I also tried RAM in different slots, too). In each case, the CPU status LED comes and very quickly goes off and the DRAM status LED comes on and stays on.

I also inspected the case, standoffs, and back of the motherboard and see no evidence of shorting. Then I put the mboard back in the case and checked again with the same results as above. I put the PSU back in the case--same thing. Finally, I put all the mboard screws and PSU screws in. On startup, the CPU status LED flickers on then off and the DRAM LED comes on and stays on. The system never POSTed.

Earlier, I said it was the CPU status LED that came on and remained on. I am still confident that is accurate.

So, the mystery deepens. I still don't know what is going on. I wonder if it is normal for the CPU status LED to flicker on, then off. Now, it seems like the CPU is fine and, instead, there is a problem with the RAM. Next week I will try to have the RAM tested, I can't do further testing myself.

According to PCPartPicker and Gskill, the RAM I'm using is compatible with this mboard. Gigabyte doesn't list this particular RAM model but listed very similar models and says their list is incomplete.

Does anyone have any advice on next steps? FWIW, I have worked through the " 'No POST', 'system won't boot', and 'no video output' troubleshooting checklist".

 

[drivinfast247]

You made sure to connect the CPU atx power to top left corner of motherboard?

BTW: The AM5 systems can sometimes take a few minutes to memory train upon boot.

 

[kataProkroustes]

You made sure to connect the CPU atx power to top left corner of motherboard?

Yes, the ATX_12V1 and ATX_12V CPU cables were connected to both the PSU and the mboard.

 

[Flayed]

So, the mystery deepens. I still don't know what is going on. I wonder if it is normal for the CPU status LED to flicker on, then off. Now, it seems like the CPU is fine and, instead, there is a problem with the RAM. Next week I will try to have the RAM tested, I can't do further testing myself.

The memory controller is part of the CPU, so I wouldn't take the status LED as gospel as to what has failed. If you have tried both sticks of RAM separately and it doesn't boot, well the chances of both sticks failing are slim, more likely it is the CPU.

 

[ohio_buckeye]

How long are you letting it sit? Sometimes am5 systems at first can take 10 minutes or so when doing memory training.

 

[kataProkroustes]

The memory controller is part of the CPU, so I wouldn't take the status LED as gospel as to what has failed. If you have tried both sticks of RAM separately and it doesn't boot, well the chances of both sticks failing are slim, more likely it is the CPU.

Good point. Thanks.

 

[kataProkroustes]

How long are you letting it sit? Sometimes am5 systems at first can take 10 minutes or so when doing memory training.

I haven't been letting it sit for long at all--well under 10 minutes. What is "memory training"? How do I know whether it is happening or not?

 

[ohio_buckeye]

Essentially your system tries to test and validate the memory. Especially its first boot up. It may very well be that you’re stopping things before it’s finishing the process.

 

[kataProkroustes]

Essentially your system tries to test and validate the memory. Especially its first boot up. It may very well be that you’re stopping things before it’s finishing the process.

I never heard of that and haven't seen anything to that effect in any troubleshooting guides or installation documentation but will perhaps give a try.