4 ms·

It is not possible for a CMOS battery to get fried this way and the machine be still able to boot. For a CMOS battery to get "fried" a number of components wou

It is not possible for a CMOS battery to get fried this way and the machine be still able to boot. For a CMOS battery to get "fried" a number of components would have to fail catastrophically. There are typically layers of protection that fail open and a much higher voltage needs to be able for them to get shorted which is what would be necessary for high voltage to reach CMOS battery. Now, I am not saying that CMOS batteries weren't hurt. I am saying that it is inconceivable that you would get number of servers that had CMOS batteries hurt and then boot up fine when they are changed for new ones. Your store does not check out.

latchkey 4y ago
> it is inconceivable that you would get number of servers that had CMOS batteries hurt and then boot up fine when they are changed for new ones. Hate to break it to you, it happened regardless of your ability to conceive things, or not.
- DiggyJohnson 4y ago
  Well put, same goes for the sibling comment from the electronics hobbyist.
- twawaaay 4y ago
  Hate to break it to you, the terminals of CMOS battery are typically almost directly attached to a number of chips that are thousands of times more fragile than the battery itself. Essentially, you can't fry a CMOS battery with a transient without also frying at least couple components that will prevent the motherboard from booting. Is it possible for a motherboard to get CMOS battery fried without frying anything else vital? Maybe... but... If you told me that you were in a roll over accident where you did not damage your car roof I would say "well, maybe, highly unlikely but sure, why not, maybe this happened to you". But if you said you were in 17 rollover accidents and in 15 of theme the roof was undamaged I would say "you are full of crap".
  - b112 4y ago
    Plus, machines boot fine with a dead CMOS battery. I can't even imagine a shorted CMOS battery preventing a boot. I don't get it.
    - latchkey 4y ago
      What is amazing is that you don't have to get it. Dead != Fried.
      - Johnythree 4y ago
        How does a dead battery prevent a reboot? The battery is isolated by a series diode to prevent it shunting the circuit. Certainly some parameters will be lost (eg time) but it should still boot. Whatever, it's easy to test. Simply remove the battery from your PC and see if it will reboot. Then clip a lead across the (vacant) battery holder to see if a shorted battery prevents a reboot.
  - latchkey 4y ago
    It is amazing that you're doubling down after getting downvoted into oblivion and then going off on car accidents? I'm surprised you aren't telling me that there is no way a bird could have fried a transformer... you know, because BIRDS AREN'T REAL. Remind me again, what motivation would I have to lie and make up a story about something like this? Ok, I give up... you are totally right. All those machines just magically fixed themselves. </facepalm>
    - Johnythree 4y ago
      I totally agree with twawaaay. There is a huge electrical separation between the incoming mains and the CMOS battery. It is very unlikely that a mains spike could damage the battery without also frying the intervening circuitry. A more likely explanation is that the faulty servers had quietly deteriorated over the years, until a mains failure caused them to reboot, thus revealing that the batteries were faulty. And if the batteries had been sitting there for sometime with an internal short, then it is also likely that they would have visible damage (eg be leaking). Also if they had been tested by simply pressing the reset button, they would likely boot just fine. However if they had the mains removed for a hour or so, it would be a different story..
tsomctl 4y ago
As a hobbyist electrical engineer, one of the most important things I've learned is that at high voltages and/or high currents, our nice lovely lumped element model is not always accurate. There's enough stray inductance and capacitance in random places that with a very fast voltage spike, anything is possible.
- latchkey 4y ago
  Thank you. Imagine a shipping container full of metal boxes sitting on metal shelves, filled with metal components in a very dusty hot dry environment with fans going in the containers and boxes, pulling megawatts of power and suddenly a bird lands on the transformer. I'd say anything with electricity is possible at that point.

latchkey 4y ago

> it is inconceivable that you would get number of servers that had CMOS batteries hurt and then boot up fine when they are changed for new ones. Hate to break it to you, it happened regardless of your ability to conceive things, or not.

DiggyJohnson 4y ago
Well put, same goes for the sibling comment from the electronics hobbyist.
twawaaay 4y ago
Hate to break it to you, the terminals of CMOS battery are typically almost directly attached to a number of chips that are thousands of times more fragile than the battery itself. Essentially, you can't fry a CMOS battery with a transient without also frying at least couple components that will prevent the motherboard from booting. Is it possible for a motherboard to get CMOS battery fried without frying anything else vital? Maybe... but... If you told me that you were in a roll over accident where you did not damage your car roof I would say "well, maybe, highly unlikely but sure, why not, maybe this happened to you". But if you said you were in 17 rollover accidents and in 15 of theme the roof was undamaged I would say "you are full of crap".
- b112 4y ago
  Plus, machines boot fine with a dead CMOS battery. I can't even imagine a shorted CMOS battery preventing a boot. I don't get it.
  - latchkey 4y ago
    What is amazing is that you don't have to get it. Dead != Fried.
    - Johnythree 4y ago
      How does a dead battery prevent a reboot? The battery is isolated by a series diode to prevent it shunting the circuit. Certainly some parameters will be lost (eg time) but it should still boot. Whatever, it's easy to test. Simply remove the battery from your PC and see if it will reboot. Then clip a lead across the (vacant) battery holder to see if a shorted battery prevents a reboot.
- latchkey 4y ago
  It is amazing that you're doubling down after getting downvoted into oblivion and then going off on car accidents? I'm surprised you aren't telling me that there is no way a bird could have fried a transformer... you know, because BIRDS AREN'T REAL. Remind me again, what motivation would I have to lie and make up a story about something like this? Ok, I give up... you are totally right. All those machines just magically fixed themselves. </facepalm>
  - Johnythree 4y ago
    I totally agree with twawaaay. There is a huge electrical separation between the incoming mains and the CMOS battery. It is very unlikely that a mains spike could damage the battery without also frying the intervening circuitry. A more likely explanation is that the faulty servers had quietly deteriorated over the years, until a mains failure caused them to reboot, thus revealing that the batteries were faulty. And if the batteries had been sitting there for sometime with an internal short, then it is also likely that they would have visible damage (eg be leaking). Also if they had been tested by simply pressing the reset button, they would likely boot just fine. However if they had the mains removed for a hour or so, it would be a different story..

tsomctl 4y ago

As a hobbyist electrical engineer, one of the most important things I've learned is that at high voltages and/or high currents, our nice lovely lumped element model is not always accurate. There's enough stray inductance and capacitance in random places that with a very fast voltage spike, anything is possible.

latchkey 4y ago
Thank you. Imagine a shipping container full of metal boxes sitting on metal shelves, filled with metal components in a very dusty hot dry environment with fans going in the containers and boxes, pulling megawatts of power and suddenly a bird lands on the transformer. I'd say anything with electricity is possible at that point.