[SOLVED] ASUS H87M-PRO no POST, no MemOK LED, fanspin, weird BIOS flashback issues.

Jul 1, 2023
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Hello everyone,
I'm an intermediate PC builder and got ahold of a new motherboard to upgrade my server. I have tested parts that ran fine on the previous MOBO and needed to upgrade due to some MOBO limitations (SATA slots, IOMMU, had weird bugs etc).
I got myself an ASUS H87M-PRO and transplanted over the working parts (i7-4790S, 2xM378B1G73QH0-CK0 DDR3 sticks with 8 gigs) and tried powering on the system.

No dice. I get CPU fanspin, but nothing else. No post, the MemOK! light (which is supposed to be blinking) never turns on and the CPU gets warm. The PSU ran fine on the previous build and had no issues, so it is very unlikely a PSU problem. Checked the cables, connections, everything is good. Checked the CPU, installed correctly, no visibly bent pins (at least to my eye, friends all agree) etc. Beeper might not work, never tested it before, but no beeps from the MOBO. Cleared the CMOS, took out the battery, done both multiple times and no dice.

I assumed it was the BIOS since on their site, they list the 4790S as compatible after a BIOS update. I went through the process of doing the BIOS flashback procedure (downloaded the compatible BIOS, renamed it, flashed it onto a FAT32 USB 2.0 stick and plopped it into the correct slot.)
Holding the reset button for 3 secs, I can see that the USB is being used (as indicated by the LED on it flashing), but then one of two things happens:

  • If the file is named XXXXX.CAP and I hold the reset button, nothing happens but the USB LED blinks continously until I let go of the button,
  • If the file is named XXXXX (without the .CAP) and I hold the reset button, the CPU fan starts spinning and the USB LED blinks for a few seconds, but then stops and the PC continues to spin without going into POST or anything. I can manually turn it off with just the power button.
  • Referring to the manual, if the case PWR light keeps solid that means there is an issue with reading the BIOS file.
I am at my wits end. I checked the RAM compatibilty and the RAM, while not listed on the compatibilty list, is a tried and tested SAMSUNG UDIMM stick. I'll be picking up a spare, compatible CPU tomorrow and another DDR3 stick just to test the system, but I thought I might as well post here before doing so in case anybody has any suggestions/fixes.

Thanks in advance and cheers!
 
This:

" Beeper might not work, never tested it before, but no beeps from the MOBO."

Install a small speaker if at all possible so any boot time beep codes can be heard.

Try a fresh CMOS battery and clear CMOS via the motherboard's User Guide/Manual.
 
Do you have an older CPU which is compatible with the BIOS? I'm hoping here that you still have a working BIOS.

I hate working blind when updating the BIOS and much prefer to see what I'm doing and read the error messages.

It might be worth buying a spare CPU. Anything in the CPU list for the mobo should do.
 
Update:
Slotting in a new CPU sent me to the BIOS screen, and after some digging I came to a sad realization:
This wasn't a h87m-pro, but instead a h87m-pro g10ac. From a prebuilt PC, this MOBO lacks many of the features and most notably the support for "newer" intels. Neither me nor the seller realized such a board existed (since the only difference is the black/green PCB background, and the stealthily placed sticker that differentiates the two boards)
Will be returning the board to the seller shortly. Thanks everyone for the help!