Three dead GA-B85M-HD3 boards

[m00se]

Hi

I've got a mysterious problem that has killed three GA-B85M-HD3 boards within one month. Having good experiences with Gigabyte otherwise I'm pretty sure this isn't a coincidence.

Three years ago I built this setup:

Motherboard: Gigabyte GA-B85M-HD3
CPU: i5-4440
Ram: Geil 8 GB DDR3-1333 Kit
PSU: Sharkoon SHA450-12EUP
HDD: Deskstar 7K1000.C, 500 GB
The case and an internal card reader were already 6 years old at the time. There is also an old Linksys WiFi card and a standard DVD drive in the computer.

About two months ago the system died. All components worked well on another computer except the motherboard. As it had been on nearly full-time I didn't to much of it and just ordered a new motherboard; GA-B85M-HD3 R4 this time.

This works well for two months. After that, again the motherboard was dead. The most likely suspect was the power supply being corrupt, so I swapped the motherboard for a new one (also GA-B85M-HD3 R4), and changed the PSU for a brand new Corsair CX430.

Only two days this time ... and motherboard number three died. You can imagine that I won't be running to the shop for a new board anymore until I really figure out what is going on. I already changed the PSU with the last motherboard replacement, so I can exclude that. However I can't really think of another component which is capable to destroy motherboards but keeps working fine itself.

We did look into the power in the house. The voltage is within 220-230 range (Belgium; that is normal voltage here), but of course we don't know exactly at the time the motherboard died. Also no other electronic devices show strange behaviour.

Just to explain, with "dead" I mean (in each of the three cases): using absolute minimum setup (CPU, one stick of RAM, PSU) nothing happens when I try to power it up (connecting Power-on on motherboard). There is no strange smell and nothing visually wrong.

So, my questions for you:
- Any idea what could cause the motherboards to fail? Number one could have just died from age (even thouh three years isn't old); but numbers 2 and 3 certainly aren't a coincidene. Please note that the system has worked each time for at least two days, so I don't think I did something wrong with the installation.
- Is there anything I could measure on the board using a multimeter that could better diagnose the problem?


Thank you very much in advance!

[shadowsports]

I'd start by stripping the system down and bench testing.  If the system is dead, this may not yield any answers.  You can perform a battery pull with the power disconnected before starting this.

Moving forward, I'd purchase a UPS with AVR and put that in between your outlet and the PSU.  From a monitoring standpoint, if you replace the board, you can get a good idea of what the board is seeing from power and temp stand point in BIOS.  Some boards also come with terminals for measuring voltage for those who are electronically inclined.    The system can run indefinitely while you watch for fluctuations in voltage and temps.  App Center allows you to record fan speed, temps and voltages for historical comparison.  Further, a good UPS will allow you to see what's going on with the power in your home.  It also provides sensitive components with an extra layer of protection.  Wall current can also be measured with a Ohms meter   

Sometimes people don't realize that a circuit in your home can share outlets in an adjoining room or wall.  If the wall of your office is on the other side of your kitchen, a major appliance could be causing a surge.  Space heaters can also cause problems.  All of this only matters if in fact power is the problem.  I'm not saying this is your issue, or that you don't know what the power situation is in your house, I'm just throwing out some suggestions. Hopefully stripping down the system and bench testing will yield more information.       

[m00se]

I'd start by stripping the system down and bench testing.  If the system is dead, this may not yield any answers.  You can perform a battery pull with the power disconnected before starting this.

Dead. Tried a battery pull but that didn't help.

Moving forward, I'd purchase a UPS with AVR and put that in between your outlet and the PSU.

I'll take this into account.

I did some testing with a multi-meter today, and I found something that looks strange:

- When I disconnect the PSU and measure between the power-on pin and ground on the PSU it's 3.5V which is ok I think.
- When I do the same measurement, but with ATX-connector and CPU-connector connected to the motherboard I get a voltage constantly fluctuating between 1V en 2.5V.
- When I then measure between the two pins where you connect the power button I also get fluctuating values, but this time between 0.5V en 1.5V.

Is this something that others recognize?