Question about recent power outage and PC

Steve C said:

As a professional scientist I think I grasped your post. The shelf life of a CR2032 battery is c. 10 years which is about 3x the practical service life when you switch off the PC when not in use - see http://data.energizer.com/pdfs/lithiumcoin_appman.pdf What does your exceedingly low quoted drain of 100-200 picomaps refer to?

That 240 ma-hours is for a battery under a specific load that would deplete a battery in hours or days. Amp-hour numbers for batteries increase significantly with less load. And decreases significantly with a larger load. A battery rated with a milliamp-hour rating of 240 will easily exceed 1000 with that pico-amp load.

Computer manufacturers clearly stated that the lithium cell would last five years in a computer - which was the shelf life of that CR2032 cell during that period (early 1980s). Today, those same coin cells have a shelf live of ten years. Even Dallas Semiconductor (that made the CMOS clock IC with a battery inside) also increased life expectancy of their IC from five years to ten years. Because battery shelf life increased that much.

Same numbers and facts were also found in IC manufacturer specs where IC that drove an LED watch (yes, note the vintage of this spec) was also used in computers as date-time clocks. That manufacturer defined power consumption also in picoamps. Power was that tiny that long ago. Today's semiconductors consume less power.

Because and again, the point: CMOS / clock circuit consumes so little power that battery life expectancy is only determined by a battery's shelf life. Anyone whose computer is only getting two years from a battery is using observation of one defective motherboard to make a recommendation. Two years contradicts what manufacturers were stating even in the 1980s - with the first PCs. Today's computer CMOS/clock batteries must now last far more than five years - without AC power applied.

PolarNettles said:

No, measure it while the battery is still installed, if possible (it would depend on the type of battery socket on your motherboard). The battery voltage changes depending on the load that's connected to it.

But since it's >3V it's highly unlikely the voltage drop under load will be significant. I wouldn't worry about it. I have changed maybe 1 or 2 batteries in the past 30 years of owning PCs.

No way of measuring the battery while seated in the PC negative side facing down in the socket. Never remember changing a battery on a board ever and used PC for many years. Thanks maybe i will change it anyway, but PC has been fine since bought a new Surge Protector.

westom said:

Volt meter is a superb diagnostic tool. If the battery is 2.8 volts, then plan to replace it in the next six months.

Another indication of a battery going bad long before it does go bad: clock will not keep accurate time when power is removed for a day or week.

From your second sentence that has never happened as of yet, it was in storage for a few months. As said most likely change it and have with the surge protector
Thanks !!

PC has been fine not positive of the cause surge protector or battery.

jds63 said:

... but PC has been fine since bought a new Surge Protector.

Potentially harmful surges occur maybe once every seven years. If surges are occurring weekly or daily, then what is protecting less robust appliances? What protects a dishwasher, dimmer switches, furnace, GFCIs, garage door opener, recharging electronics, clock radios, refrigerator, LED & CFL bulbs, central air, and smoke detectors? A protector too close to appliances can even make surge damage easier.

Something completely different, called a surge protector, is necessary to even protect an adjacent protector. If that protector is doing anything, then computer hardware was already damaged. Surges do not cause strange operation. Surges do permanent hardware damage.

westom said:

Potentially harmful surges occur maybe once every seven years. If surges are occurring weekly or daily, then what is protecting less robust appliances? What protects a dishwasher, dimmer switches, furnace, GFCIs, garage door opener, recharging electronics, clock radios, refrigerator, LED & CFL bulbs, central air, and smoke detectors? A protector too close to appliances can even make surge damage easier.

Something completely different, called a surge protector, is necessary to even protect an adjacent protector. If that protector is doing anything, then computer hardware was already damaged. Surges do not cause strange operation. Surges do permanent hardware damage.

Thanks for the info i live in a apartment in a private house my A/V Receiver, TV ,blu-ray and other electronics on a surge protector. All i have is separate circuit breakers for different outlets in the apt.. PC was fine before new surge protector but since this one had issues with Green Power outlets i decided to change i also changed the 3V battery on the board.

Gigabyte support could only say something possibly corrupted the BIOS config. and caused it to not power up and by re-seating the battery brought it back to default settings, but as far as i can see i did not have to reflash the BIOS. A guess by them from what i told them occurred if caused by power outage or not. Yes i would of figured there would be permanent damage if it was a bad surge. Glad it is working and not fried.

jds63 said:

Gigabyte support could only say something possibly corrupted the BIOS config. and caused it to not power up and by re-seating the battery brought it back to default settings, but as far as i can see i did not have to reflash the BIOS.

BIOS is in non-volatile memory. It is not (easily) corrupted. BIOS configuration is CMOS. This is battery backup memory. To be corrupted means a current must have passed through that circuit - ie through the underlying copper ground plane.

That current could be something as simple as a static electric discharge. A motherboard must be mounted in a way that such currents do not exist. Start with a fundamental concept. Electricity means both an incoming and outgoing path must exist. Eliminate one and that current does not exist.

So that stray currents (such as a static discharge or other noise currents) do not exist, a motherboard is best mounted with only one electrically conductive standoff; typically located near the DC power connector and peripheral cards. Then a static discharge current does not pass through the motherboard's copper ground plane.

That is a possible suspect. Making a single point connection between motherboard and chassis will make the entire computer more resilient. But that is only one possible suspect for corrupting a CMOS. Corruption that occurs irrelevant of battery voltage.

westom said:

BIOS is in non-volatile memory. It is not (easily) corrupted. BIOS configuration is CMOS. This is battery backup memory. To be corrupted means a current must have passed through that circuit - ie through the underlying copper ground plane.

That current could be something as simple as a static electric discharge. A motherboard must be mounted in a way that such currents do not exist. Start with a fundamental concept. Electricity means both an incoming and outgoing path must exist. Eliminate one and that current does not exist.

So that stray currents (such as a static discharge or other noise currents) do not exist, a motherboard is best mounted with only one electrically conductive standoff; typically located near the DC power connector and peripheral cards. Then a static discharge current does not pass through the motherboard's copper ground plane.

That is a possible suspect. Making a single point connection between motherboard and chassis will make the entire computer more resilient. But that is only one possible suspect for corrupting a CMOS. Corruption that occurs irrelevant of battery voltage.

Whatever the cause, I've had the same problem with a Gigabyte motherboard as the OP with the case closed in normal operation. I assumed a power spike was the cause. Perhaps the impact of secondary particles from high energy cosmic rays is an alternative explanation?

Steve C said:

Perhaps the impact of secondary particles from high energy cosmic rays is an alternative explanation?

Ground plane is a large sheet of copper inside the motherboard. A significant voltage difference exists across that sheet. That voltage difference is irrelevant (due to its design) for electrical currents that are expected But it creates problems for undesirable currents that enter and exit a board at two ends.

Many decades ago, energy particles were a problem especially to memory. That defect was traced to radioactive material inside the IC packaging material. Extremely unlikely that an IC only on Gigabyte boards has that problem. But using multiple electrically conductive standoffs has created computer problems.

Since changing CMOS battery and Surge Protector there has not been anymore issues with my PC not powering on. Thanks for all the help and info.