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There are multiple CPUs not posting on LGA1700 boards

There are multiple CPUs not posting on LGA1700 boards

C
Cutie_Kitcat
Senior Member
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644
11-20-2025, 05:38 PM
#1
I’m working through this hardware puzzle and would value some advice.
My setup includes:
CPUs – i7-12700KF, i9-12900K, i3-12100
Boards – two LGA1700 units (one confirmed good, one uncertain), both Z690 Asus boards

What I observe:
- With the i3-12100 or i9-12900K, the system boots up, but the CPU LED stays lit and the VRMs only deliver about 0.3 V. No POST occurs.
- When no CPU is installed, the board remains powered, and the VRMs sit at roughly 1.05 V.
- I checked the sockets with a macro lens – no bent pins were visible.
- Measurements show the CPU pads on the CPUs read around 120 Ω to ground, indicating no obvious short circuit (verified with IHS).
- The VSS to VCORRI pads appear shorted? VRMs output ~0.3 V when a CPU is inserted but fail to initialize.
- With the i7, the PSU immediately enters protection mode, as if detecting an overcurrent or short.

What’s puzzling me:
The i7 worked fine before; the i3 was supposed to be tested by the seller. Now neither CPU boots on either board.
My goal is to test a budget Celeron G6900 (with iGPU) to see if it reveals the issue.
Questions:
- Could a bad board truly disable multiple CPUs like this, or am I facing a rare failure?
- Does the pattern of readings – low Vcore, red LED, PSU shutdown on i7 – suggest dead chips or defective boards?
- Any additional checks I should perform before receiving the Celeron?
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C
Cutie_Kitcat
11-20-2025, 05:38 PM #1

I’m working through this hardware puzzle and would value some advice.
My setup includes:
CPUs – i7-12700KF, i9-12900K, i3-12100
Boards – two LGA1700 units (one confirmed good, one uncertain), both Z690 Asus boards

What I observe:
- With the i3-12100 or i9-12900K, the system boots up, but the CPU LED stays lit and the VRMs only deliver about 0.3 V. No POST occurs.
- When no CPU is installed, the board remains powered, and the VRMs sit at roughly 1.05 V.
- I checked the sockets with a macro lens – no bent pins were visible.
- Measurements show the CPU pads on the CPUs read around 120 Ω to ground, indicating no obvious short circuit (verified with IHS).
- The VSS to VCORRI pads appear shorted? VRMs output ~0.3 V when a CPU is inserted but fail to initialize.
- With the i7, the PSU immediately enters protection mode, as if detecting an overcurrent or short.

What’s puzzling me:
The i7 worked fine before; the i3 was supposed to be tested by the seller. Now neither CPU boots on either board.
My goal is to test a budget Celeron G6900 (with iGPU) to see if it reveals the issue.
Questions:
- Could a bad board truly disable multiple CPUs like this, or am I facing a rare failure?
- Does the pattern of readings – low Vcore, red LED, PSU shutdown on i7 – suggest dead chips or defective boards?
- Any additional checks I should perform before receiving the Celeron?

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M
mcDavoz
Senior Member
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544
11-20-2025, 05:38 PM
#2
Perhaps the psu is at fault.
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M
mcDavoz
11-20-2025, 05:38 PM #2

Perhaps the psu is at fault.

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H
hosino0724
Member
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60
11-20-2025, 05:38 PM
#3
It's brand new, but I tested it on a completely different system (i7 7700) to verify the PSU is actually functioning and that the system boots properly without any problems.
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H
hosino0724
11-20-2025, 05:38 PM #3

It's brand new, but I tested it on a completely different system (i7 7700) to verify the PSU is actually functioning and that the system boots properly without any problems.

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W
Willtrc
Junior Member
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27
11-20-2025, 05:38 PM
#4
If you encounter difficulties with a standard motherboard, power supply unit, and processor, consider alternatives. Check if your wall power is correctly phased and properly grounded. A basic outlet tester costs around ten dollars.
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W
Willtrc
11-20-2025, 05:38 PM #4

If you encounter difficulties with a standard motherboard, power supply unit, and processor, consider alternatives. Check if your wall power is correctly phased and properly grounded. A basic outlet tester costs around ten dollars.

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A
Autobotforever
Member
Find
103
11-20-2025, 05:38 PM
#5
right now i have no idea what's working and what's not. i only know my plug and psu are fine, they work with other systems without any issues. i'm curious if a motherboard could be so damaged that it stops the cpu completely. i checked the vrms on the board without a cpu installed to see the default behavior. i was hoping to find one vrm that lets the full 12v through to the cpu, which would explain why it could fry a good cpu instantly, but nothing happened. all the vrms were showing 1.05v.
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Autobotforever
11-20-2025, 05:38 PM #5

right now i have no idea what's working and what's not. i only know my plug and psu are fine, they work with other systems without any issues. i'm curious if a motherboard could be so damaged that it stops the cpu completely. i checked the vrms on the board without a cpu installed to see the default behavior. i was hoping to find one vrm that lets the full 12v through to the cpu, which would explain why it could fry a good cpu instantly, but nothing happened. all the vrms were showing 1.05v.

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