Re: [GTALUG] war story: CMOS battery AKA Real Time Clock (RTC) battery in a notebook

[Stewart C. Russell via talk]

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

---
Post to this mailing list talk@gtalug.org
Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk

Re: [GTALUG] war story: CMOS battery AKA Real Time Clock (RTC) battery in a notebook

[Dave Collier-Brown via talk]

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 
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


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.

---
Post to this mailing list talk@gtalug.org
Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk



---
Post to this mailing list 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-br...@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.
---
Post to this mailing list talk@gtalug.org
Unsubscribe from this mailing list https://gtalug.org/mailman/listinfo/talk