war story: CMOS battery AKA Real Time Clock (RTC) battery in a notebook
Almost all PCs have settings that they want to keep while the computer is off or even unplugged. Ones that they don't want to keep on disk. Things you set up from the firmware setup screen. Furthermore, they have a realtime clock that runs when the machine is turned off or unplugged. These are all powered by a lithium coin cell. Eventually, that battery runs down and you have to replace it. Five or ten years of lifetime seems normal. When it runs down, the computer will forget the date, time, and all its setting when it is turned off. This is annoying: every time you start up you have to fill in the time and other settings. Luckily, for most computers it is easy to replace: it is in a socket in the motherboard. The battery can be sourced from Dollarama or Amazon for a buck or two. Just get the size right. For (some? all?) notebooks the coin cell battery isn't used if there is a charge in the main battery. So you may not notice that the coin cell battery is failing. I flattened my notebook's main battery somehow (left it sleeping for a week?). When I powered it on, it had no idea of the time nor what to boot. Upon investigation, I find that I have to completely disassemble my computer to replace the battery! They placed it on the top of the main board whereas access is to the bottom. If you care, you can read page 50 of <https://dl.dell.com/topicspdf/xps-15-9560-laptop_setup-guide_en-us.pdf> It looks as if I will need some new thermal grease since I have to remove the heat sink from the processor. And the coin cell assembly is not generic -- no Dollarama battery. <https://www.amazon.ca/LeFix-Replacement-Battery-Connector-Precision/dp/B082G35D4R/>
That is such terrible design. They could have put the CMOS battery anywhere, like somewhere serviceable. On Wed, 19 Oct 2022 at 19:58, D. Hugh Redelmeier via talk <talk@gtalug.org> wrote:
Almost all PCs have settings that they want to keep while the computer is off or even unplugged. Ones that they don't want to keep on disk. Things you set up from the firmware setup screen.
Furthermore, they have a realtime clock that runs when the machine is turned off or unplugged.
These are all powered by a lithium coin cell.
Eventually, that battery runs down and you have to replace it. Five or ten years of lifetime seems normal.
When it runs down, the computer will forget the date, time, and all its setting when it is turned off. This is annoying: every time you start up you have to fill in the time and other settings.
Luckily, for most computers it is easy to replace: it is in a socket in the motherboard. The battery can be sourced from Dollarama or Amazon for a buck or two. Just get the size right.
For (some? all?) notebooks the coin cell battery isn't used if there is a charge in the main battery. So you may not notice that the coin cell battery is failing.
I flattened my notebook's main battery somehow (left it sleeping for a week?). When I powered it on, it had no idea of the time nor what to boot.
Upon investigation, I find that I have to completely disassemble my computer to replace the battery! They placed it on the top of the main board whereas access is to the bottom. If you care, you can read page 50 of <https://dl.dell.com/topicspdf/xps-15-9560-laptop_setup-guide_en-us.pdf>
It looks as if I will need some new thermal grease since I have to remove the heat sink from the processor. And the coin cell assembly is not generic -- no Dollarama battery. < https://www.amazon.ca/LeFix-Replacement-Battery-Connector-Precision/dp/B082G...
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As Honda once said in an owner's manual, "engine does not contain any service parts". I think you were supposed to throw the bike away when the oil got dirty (;-) --dave On 10/19/22 21:10, Don Tai via talk wrote: That is such terrible design. They could have put the CMOS battery anywhere, like somewhere serviceable. On Wed, 19 Oct 2022 at 19:58, D. Hugh Redelmeier via talk <talk@gtalug.org<mailto:talk@gtalug.org>> wrote: Almost all PCs have settings that they want to keep while the computer is off or even unplugged. Ones that they don't want to keep on disk. Things you set up from the firmware setup screen. Furthermore, they have a realtime clock that runs when the machine is turned off or unplugged. These are all powered by a lithium coin cell. Eventually, that battery runs down and you have to replace it. Five or ten years of lifetime seems normal. When it runs down, the computer will forget the date, time, and all its setting when it is turned off. This is annoying: every time you start up you have to fill in the time and other settings. Luckily, for most computers it is easy to replace: it is in a socket in the motherboard. The battery can be sourced from Dollarama or Amazon for a buck or two. Just get the size right. For (some? all?) notebooks the coin cell battery isn't used if there is a charge in the main battery. So you may not notice that the coin cell battery is failing. I flattened my notebook's main battery somehow (left it sleeping for a week?). When I powered it on, it had no idea of the time nor what to boot. Upon investigation, I find that I have to completely disassemble my computer to replace the battery! They placed it on the top of the main board whereas access is to the bottom. If you care, you can read page 50 of <https://dl.dell.com/topicspdf/xps-15-9560-laptop_setup-guide_en-us.pdf> It looks as if I will need some new thermal grease since I have to remove the heat sink from the processor. And the coin cell assembly is not generic -- no Dollarama battery. <https://www.amazon.ca/LeFix-Replacement-Battery-Connector-Precision/dp/B082G35D4R/> --- Post to this mailing list talk@gtalug.org<mailto:talk@gtalug.org> Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk --- Post to this mailing list talk@gtalug.org<mailto:talk@gtalug.org> Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest dave.collier-brown@indexexchange.com<mailto:dave.collier-brown@indexexchange.com> | -- Mark Twain CONFIDENTIALITY NOTICE AND DISCLAIMER : This telecommunication, including any and all attachments, contains confidential information intended only for the person(s) to whom it is addressed. Any dissemination, distribution, copying or disclosure is strictly prohibited and is not a waiver of confidentiality. If you have received this telecommunication in error, please notify the sender immediately by return electronic mail and delete the message from your inbox and deleted items folders. This telecommunication does not constitute an express or implied agreement to conduct transactions by electronic means, nor does it constitute a contract offer, a contract amendment or an acceptance of a contract offer. Contract terms contained in this telecommunication are subject to legal review and the completion of formal documentation and are not binding until same is confirmed in writing and has been signed by an authorized signatory.
On 2022-10-19 19:58, D. Hugh Redelmeier via talk wrote:
And the coin cell assembly is not generic -- no Dollarama battery.
I've seen that heat-shrink-on-a-flying-lead type battery on some single board computers and even some particularly enlightened microcontroller boards. The Radxa boards (like the x86 Rock Pi X, and the upcoming "Raspberry Pi Killer" ROCK 4) use them for sure. Guess your future holds Dollarama, some careful soldering plus a couple of wraps of Super 88. I guess there isn't room for the chunky half-AA size Li-SoCl2 cell that older machines used to use. There was one of these soldered into a late-80s Apple IIgs I received recently. It was still keeping the NVRAM and clock ticking despite being 25 years past its use-by date. Also, lithium–thionyl chloride batteries are now considered hazardous, so maybe it's best if they are left in the past. cheers, Stewart
On Wed, Oct 19, 2022 at 07:58:04PM -0400, D. Hugh Redelmeier via talk wrote:
Almost all PCs have settings that they want to keep while the computer is off or even unplugged. Ones that they don't want to keep on disk. Things you set up from the firmware setup screen.
Furthermore, they have a realtime clock that runs when the machine is turned off or unplugged.
These are all powered by a lithium coin cell.
Eventually, that battery runs down and you have to replace it. Five or ten years of lifetime seems normal.
When it runs down, the computer will forget the date, time, and all its setting when it is turned off. This is annoying: every time you start up you have to fill in the time and other settings.
Luckily, for most computers it is easy to replace: it is in a socket in the motherboard. The battery can be sourced from Dollarama or Amazon for a buck or two. Just get the size right.
For (some? all?) notebooks the coin cell battery isn't used if there is a charge in the main battery. So you may not notice that the coin cell battery is failing.
I flattened my notebook's main battery somehow (left it sleeping for a week?). When I powered it on, it had no idea of the time nor what to boot.
Upon investigation, I find that I have to completely disassemble my computer to replace the battery! They placed it on the top of the main board whereas access is to the bottom. If you care, you can read page 50 of <https://dl.dell.com/topicspdf/xps-15-9560-laptop_setup-guide_en-us.pdf>
Sheesh that's dumb. Of course I had to disassemble my wife's compaq laptop many times years ago to resolder the power connector that kept breaking off the board. Terrible crap.
It looks as if I will need some new thermal grease since I have to remove the heat sink from the processor. And the coin cell assembly is not generic -- no Dollarama battery. <https://www.amazon.ca/LeFix-Replacement-Battery-Connector-Precision/dp/B082G35D4R/>
I was recently playing around with my 486 (from 1993). Much to my surprise the CR2032 is still keeping the settings just fine. Says Sony and made in japan on the battery. I guess they made good batteries. Good thing it uses one of those rather than those horrible varta batteries that leaked all over the place that were common in the 1980s. I am impressed at the battery still working after 29 years. -- Len Sorensen
486x wow. 29 year old battery, that's a battery a bunny could really cheer for. Most of my 20+ year old desktop PCs all arrive with dead batteries. Thankfully they are easy to change. On Fri, 21 Oct 2022 at 22:15, Lennart Sorensen via talk <talk@gtalug.org> wrote:
On Wed, Oct 19, 2022 at 07:58:04PM -0400, D. Hugh Redelmeier via talk wrote:
Almost all PCs have settings that they want to keep while the computer is off or even unplugged. Ones that they don't want to keep on disk. Things you set up from the firmware setup screen.
Furthermore, they have a realtime clock that runs when the machine is turned off or unplugged.
These are all powered by a lithium coin cell.
Eventually, that battery runs down and you have to replace it. Five or ten years of lifetime seems normal.
When it runs down, the computer will forget the date, time, and all its setting when it is turned off. This is annoying: every time you start up you have to fill in the time and other settings.
Luckily, for most computers it is easy to replace: it is in a socket in the motherboard. The battery can be sourced from Dollarama or Amazon for a buck or two. Just get the size right.
For (some? all?) notebooks the coin cell battery isn't used if there is a charge in the main battery. So you may not notice that the coin cell battery is failing.
I flattened my notebook's main battery somehow (left it sleeping for a week?). When I powered it on, it had no idea of the time nor what to boot.
Upon investigation, I find that I have to completely disassemble my computer to replace the battery! They placed it on the top of the main board whereas access is to the bottom. If you care, you can read page 50 of <https://dl.dell.com/topicspdf/xps-15-9560-laptop_setup-guide_en-us.pdf>
Sheesh that's dumb. Of course I had to disassemble my wife's compaq laptop many times years ago to resolder the power connector that kept breaking off the board. Terrible crap.
It looks as if I will need some new thermal grease since I have to remove the heat sink from the processor. And the coin cell assembly is not generic -- no Dollarama battery. < https://www.amazon.ca/LeFix-Replacement-Battery-Connector-Precision/dp/B082G...
I was recently playing around with my 486 (from 1993). Much to my surprise the CR2032 is still keeping the settings just fine. Says Sony and made in japan on the battery. I guess they made good batteries. Good thing it uses one of those rather than those horrible varta batteries that leaked all over the place that were common in the 1980s. I am impressed at the battery still working after 29 years.
-- Len Sorensen --- Post to this mailing list talk@gtalug.org Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk
On Fri, Oct 21, 2022 at 10:51:16PM -0400, Don Tai wrote:
486x wow. 29 year old battery, that's a battery a bunny could really cheer for. Most of my 20+ year old desktop PCs all arrive with dead batteries. Thankfully they are easy to change.
Yeah I actually popped out the battery and thought I should go get a new one, then checked the voltage and put it back in since it was fine. -- Len Sorensen
participants (5)
-
D. Hugh Redelmeier -
Dave Collier-Brown -
Don Tai -
Lennart Sorensen -
Stewart C. Russell