Weak CMOS Battery May Prevent Your Computer from Booting!

[Fly Guy]

For the last two years I couldn't figure out why my three year old computer wouldn't boot. It wouldn't turn on after a power outage. And even if I did properly shut down the computer the night before, it still wouldn't turn on the next morning. I would have to drain the computer by disconnecting the PSU. At first it was a few minutes, then it gradually took a whole day for the computer to drain, then only would the computer boot up. What confused me was the computer worked like a champ when the computer decided to power on.

Then just last week my computer acted even more strange than what I've described above. The computer would power up after pressing the power button but then it would immediately shut down after two seconds. I looked online and the comments were mostly, "The culprit is most likely the PSU. You need to test your computer with another PSU."

Another person with similar computer issues like me jumped through loops with the advice they gave him online, e.g. re-seat hardware, install another PSU, etc. None worked so he decided to change CMOS battery. The computer then worked like a champ again and has no problem booting. And so did this too work for me. No costly unnecessry PSU, CPU, RAM, MOBO replacement.

Anyone has any theories as to why a weak CMOS battery would prevent the computer from booting and shutting down mid way before a complete boot? It's ridiculous. You will not find this advice on the web that the CMOS battery could be the culprit because as they explain, "The purpose of the CMOS battery is to only hold date and time. A dead or weak CMOS battery will not prevent the computer from booting. You'll just lose date and time."

[Washell]

Is this still going? In other recent news, water turns out to be wet!

Next up the sky is... blue?

[spoonman3068]

I couldn't get my machine to boot up, despite testing the power supply etc. So I cleaned out the area around the battery and felt that it had come slightly detached. I pushed it back into place and the system booted up immediately. Bizarre, but it worked.

The lesson here is, CHECK YOUR BATTERY, even if it doesn't make sense.

Thanks 'Fly Guy'

[ghmj07]

Old thread, I know . . . but just replaced CMOS on 4-year old PC because it didn't recognize boot drive when I'd turn it on. I booted with a USB Win drive, and it recognized the drives, but when starting the PC normally, the BIOS didn't see any drives. Replaced the battery, problem solved.

I've also had a couple of other weird problems that replacing the CMOS solved. I've been toying with PCs for about 25 years, and I do tend to keep them for several years.

[Gatuno]

Nooo guys! The dread CMOS battery issue is happening again on my Dell 5547!

First it started with the time being hours wrong, and then after almost 1 year of time issues, today, I got the 5 beeps of depression.

My Country is still on lockdown because of covid19 and I don't know anyone who could change it for me, and even if I wanted to do it myself, I can't cuz I lack the tools.

But one thing I noticed, is that after I leave my laptop beeping for 1 minute and turned it off, I was able to turn it on again (but he was connected through the power cable)

Maybe this info could be a temporary fix for anyone who desperate needs to power on their laptops.

Perhaps I was lucky enough this time, or maybe the CMOS is on it last of the last. I'll leave the power cable connected when I go to sleep and turn off my laptop, and see if the power cable trick will do something and post the result here asap!

Edit: Yes, my idea worked. If you laptop has a dead CMOS and it do not have it internal battery anymore due completly failure and you had to remove it and use the laptop through power cable from now on (like me lmao), leave the power cable connected to your laptop and connected to your outlet so the cable can continue to power the motherboard, that way, the CMOS battery will not be needed by the system, and you won't have trouble turning your laptop on because of dead CMOS battery.

This also happens to people who still have their internal laptop battery working. Your CMOS battery might be dead, but since you still have your laptop internal battery working and feeding your motherboard, your CMOS battery isn't needed because your internal battery is already doing the job of maintain your CMOS powered. The CMOS battery only kicks in when your system is completly out of incoming power (from internal battery or power cable) and if you have a CMOS battery dead, once you cut off both main source of power, the 5 beeps of death will be heard.

For reference, my laptop is a Dell Inspiron 15 5547 but the i7 4510u CPU version.

[DarthSidious666]

โพสต์ดั้งเดิมโดย Gatuno:

Replacing a dead CMOS battery is super easy to do yourself, you just need the old one so you order the correct part.

[Gatuno]

โพสต์ดั้งเดิมโดย DarthSidious666:

โพสต์ดั้งเดิมโดย Gatuno:

Replacing a dead CMOS battery is super easy to do yourself, you just need the old one so you order the correct part.

I can't my dood. I have no tools here. To change the battery of my Dell 5547 I'll have to disassemble half of my laptop so I can reach the CMOS lol.

I kinda of regreat buying this model. The Dell 5547 is close to a Dell Ultrabook, so everything is tight inside it and hard to access.

[Bad 💀 Motha]

โพสต์ดั้งเดิมโดย Gatuno:

โพสต์ดั้งเดิมโดย DarthSidious666:

Replacing a dead CMOS battery is super easy to do yourself, you just need the old one so you order the correct part.

I can't my dood. I have no tools here. To change the battery of my Dell 5547 I'll have to disassemble half of my laptop so I can reach the CMOS lol.

I kinda of regreat buying this model. The Dell 5547 is close to a Dell Ultrabook, so everything is tight inside it and hard to access.

But thats basically any Laptop to be honest, Ultra book doesn't have anything to do with it. They are all pretty much the same inside to where you must remove at least the keyboard and bottom panels to access anything. Go lookup your laptop models motherboard so you can see where exactly the cmos battery is located. Most laptops use a shrink-wrapped battery with a 2 wire plug on it, so either will have to "rig" a new battery for that to work, or go on ebay and buy a replacement cmos battery that comes shrink-wrapped with the wiring already on it, then replace what you have. You should be able to find parts on ebay by typing the motherboard model from the laptop into the search

[Gatuno]

โพสต์ดั้งเดิมโดย Bad 💀 Motha:

โพสต์ดั้งเดิมโดย Gatuno:

I can't my dood. I have no tools here. To change the battery of my Dell 5547 I'll have to disassemble half of my laptop so I can reach the CMOS lol.

I kinda of regreat buying this model. The Dell 5547 is close to a Dell Ultrabook, so everything is tight inside it and hard to access.

But thats basically any Laptop to be honest, Ultra book doesn't have anything to do with it. They are all pretty much the same inside to where you must remove at least the keyboard and bottom panels to access anything. Go lookup your laptop models motherboard so you can see where exactly the cmos battery is located. Most laptops use a shrink-wrapped battery with a 2 wire plug on it, so either will have to "rig" a new battery for that to work, or go on ebay and buy a replacement cmos battery that comes shrink-wrapped with the wiring already on it, then replace what you have. You should be able to find parts on ebay by typing the motherboard model from the laptop into the search

Well again I'll say it.

I do not have the tools. I don't have screwdrivers, nor anything to easily remove the keyboard right now. I know how is my laptop inside because I opened it once when I had the tools, thats why I can't do anything right now and I'm looking for other solutions for my current problem which I already found and I'll edit my previous post with the answer.

[kennyH]

Damn. Wish I had read this topic earlier. I have the same issue today: the pc won't boot up - no BIOS code, no spining fan, no signal, no nothing. PSU, RAM, CPU are okay. Reseting bios doesn't help. I thought there must be a problem with the motherboard (Z87) but I don't really know what was the specific problem. After researching for a few days and wasting money. It turns out that my CMOS battery was low and the solution was simply replacing it. I was shocked by how simple it is and how stupid am I that I couldn't figure out the problem. In addition, I can't believe that such high-end expensive computer component could be negatively affected by just a weak $2 battery. Now I'm in depression
I know this thread was made in 2015, but thx anyway

[SeriousCCIE]

yeah so I'll agree and state that my PC's CMOS battery dies about every six months, so I bought a pack of batteries and have them nearby so I can pop the old one out and the new one in should the PC not power on.

It didn't require any tools to replace, just a fingernail and some patience.

as to it being in a laptop, i needed a couple of tiny screwdrivers and even more patience, but I didn't have to really crack it open. On mine, at least, there was a panel on the bottom that let me access where to stick ram and the wifi card and whatever; the battery was there, too.

I agree it is a bummer when laptop cmos batteries go bad. Turning it off and expecting to use it... like a laptop... becomes a challenge.

[[☥] - CJ -]

Every 6 months...?
Even with a laptop it shouldnt be doing that unless theres an issue with the laptops battery pack or you keep it off the AC

For a PC that would only happen if for whatever reason the PSU is turned off and or gets unplugged a lot for whatever reason.

My PC is still using its original CMOS battery from 2012, but my PC is always on and rarely ever unpowered.

[Bad 💀 Motha]

They should last 3+ years easy.
They have a shelf life of around 10 years, which means even when PC is on all the time and battery is not used, it should hold its charge voltage very well over time still.

Maybe you're buying junk batteries.

Buy Energizer or Duracell, nothing else.

[KatBoXChimpacide]

Hey everyone, I got a question here, I am going to swap out my CMOS battery when I get home, but my issue is that my PC works perfectly fine, until I change a setting in BIOS. Doesn't matter what it is, It can be fan settings, RAM clock speeds, anything at all. The second I make my changes and save and restart, PC bricks, wont boot up. The board will go into a repair mode but after that, all I get is a flashing marker on the top left corner of the monitor and usually Error 62 in Dr Debug. I got an Asrock B550 Extreme4 by the way. So I am at a loss. Once I power down completely, pop the battery, wait a bit and re apply it, it works again fine on default settings. But that sucks, I should be able to use my PC with my specifications! The board is brand new, I am wondering if maybe the battery is defective. I got one ready to swap, so when I get home I will try it. But I haven't been able to find anyone with my issue specifically So I am kind of worried.

[kennyH]

โพสต์ดั้งเดิมโดย KatBoxSuicide:

Hey everyone, I got a question here, I am going to swap out my CMOS battery when I get home, but my issue is that my PC works perfectly fine, until I change a setting in BIOS. Doesn't matter what it is, It can be fan settings, RAM clock speeds, anything at all. The second I make my changes and save and restart, PC bricks, wont boot up. The board will go into a repair mode but after that, all I get is a flashing marker on the top left corner of the monitor and usually Error 62 in Dr Debug. I got an Asrock B550 Extreme4 by the way. So I am at a loss. Once I power down completely, pop the battery, wait a bit and re apply it, it works again fine on default settings. But that sucks, I should be able to use my PC with my specifications! The board is brand new, I am wondering if maybe the battery is defective. I got one ready to swap, so when I get home I will try it. But I haven't been able to find anyone with my issue specifically So I am kind of worried.

By this time you should have swapped your battery. Let me guess, it doesn't change anything, the problem is still there isn't it? How can a battery that comes with a new motherboard at a weak energy level

[[☥] - CJ -]

Well
its unlikely but its possible

But yeah, i dont think it has to do with a bad battery.

Have you tried updating the BIOS? that would be the closest thing to being able to fix an issue with BIOS related settings