Asrock H87-Pro4 Rev. G/A 1.04: Power cycling on reset only

[MyBrainIsAStrainer]

Hi!

I have a weird one for you. I have a H87-Pro4 from Asrock that power cycles. But only when you do a restart after it was already running!

Symptoms in detail:

1. I switch off the ATX PSU for ~15-20 seconds, then switch it back on again.
2. I press power button. The board boots without issues.
3. I can shut down the board any way I want (via OS* menu, or pushing the power button - either in the OS or the boot manager).
4. Push power button again, board boots fine.
5. This shutdown/powerup can be repeated multiple times without problems.
6. BUT: If I do a restart instead of a shutdown (whether via OS menu, pressing Ctrl+Alt+Del in the boot manager, or hitting the reset switch), then the board starts to power cycle.
7. It will continue to do so, even if you reset or use the power button again.
8. The only way to stop the cycle is to switch off the ATX supply for >15s. And then you're back at step 1.

During the power cycle:

1. The power LED comes on.
2. The fans from the CPU cooler and PSU spin up.
3. There is activity on the chip select and data lines of the BIOS EEPROM.
4. But no picture on monitor. No beeps from the speaker.
5. The power LED goes out again.
6. Fans spin down.
7. Then it starts over again from the beginning.

Things I've tried/checked:

• Removed everything from the board except RAM and CPU.
• Replaced the RAM.
• Not replaced the CPU (I have no replacement at hand, but I doubt it's the CPU anyway).
• Replaced ATX power supply.
• BIOS reset.
• Checked CMOS battery (3.1V when in socket - seems fine to me).
• Flashed newest BIOS (beta).
• Flashed latest stable BIOS.
• Removed RAM completely. Board complains with 3 long beeps, even after reset (no power cycling).
• Visual inspection of the board, no obvious issues.
• Thermal inspection. Aside from the CPU nothing gets particularly hot. The hottest component is the heat sink on the PCH with about 22°C above ambient, which is normal according what I read.
• Checked voltage rails. No differences between working boot and the power cycle state that I could find (other than the obvious one that the voltages cut in and out when it cycles).

The only other curiosity about this board is that Windows took a very long time to boot. A check of the event log showed that the Intel ME failed to start with some checksum errors. But that error disappeared after flashing the BIOS (see above). My guess is that there was some bitrot in the EEPROM. Not sure how this could be related to the other issue, however.

Any suggestions? I'm a little confused by this problem.


* Everything regarding OS was tried with both Windows 10 and Debian 11

[Peter Snieder]

Hi,

I have the same Motherboard with the exact same problem. I also have gone through all the steps you described. Have you figured out, what the problem could be? I put the board aside as I suspected a faulty chipset.

BR
Peter

[rogfanther]

Have you tried it with the board out of the case ? I have fixed a couple of different boards, even from HP/Dell pcs, where the reset button was at fault, and would "work" on its own .