CMOS battery ?

[fenix]

I've read (Scott Muellers 12th) that on modern motherboards, the CMOS setup info is held within the RTC chip and it has a long life battery integrated into it also. So when you see a silver button type battery on a motherboard, is this the older style mobo that powered the CMOS RAM settings in the BIOS chip, instead of them being stored in a RTC chip ?

I'd appreciate if someone can straighten this out for me, I'm reading some conflicting explanations. thank you.

 

[edfair]

Not a heavy user of bleeding edge stuff, but those I've seen recently still seem to have more coin batteries.
My personal preference would be to stay with a board designer that provides a separate battery.
Nothing like trying to find a specific IC rtc to fit on a one of a kind MB. This isn't a new issue. One printer I service has a dallas chip installed. When the setups fail the board goes back for a $135.00 repair. But I have to be honest and say that when the earlier board with a separate battery fails the board goes in for the same repair. But this is more an issue of vendor specific parts.
I think the real issue is more one of economics. RTC is cheap, battery holder is cheap, battery is cheap. When you are selling on price you use cheap.
When you are selling on quality, with a longer warranty, you tend to use higher price parts that have longer than 1 year max lifetime. It tends to cut down on the returns. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[paparazi]

Hey I might be wrong but the way that I understand it is you have the permanant flash memory that remains on the Eprom chip regardless of the battery being in place, and then the volitile bios information that is lost when the battery is removed or jumper discharged.
The lithium 2032 button battery lasts for up to five years and is there only to hold onto your personal bios settings, your settings obviously depend on lots of things: what type of Video card PCI/AGP, memory type and speed, which device and in what order do you want to boot.
etc,etc,etc. From the shop most are just set to Default or if your lucky Best settings, but in the majority of cases some extra settings can be optimized for your particular rig to eeek out every ounce of performance. Martin Vote if you found this post helpful please!!

 

[edfair]

Being stuck on Muellers sixth, I think, where external plugs were just coming into style, I don't know what they are putting on boards now. But I think the implecation is something like the Dallas chip. Clock , cmos, battery in a 24 pin chip that is a little taller than a 2764. Or maybe a later version of it. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[fenix]

hi , thx for all the responses. I found this today and maybe it'll be useful to someone so I'll post it, cheers..
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Various types of clock chips have been used on different motherboards. On many motherboards the RTC is integrated into the chipset, which is not replaceable. Usually, the RTC is a separate chip, although it will often be a soldered-on surface-mount chip, which is not replaceable. There is one type of RTC that is easily replaceable - the Dallas DS1287/1287A/12887/12887A family. In most cases, these chips can be replaced with the Dallas DS12C887, a Y2K compliant RTC released by Dallas Semiconductor in December of 1997. There are also compatible RTCs made by other manufacturers, which may be replaced with the DS12C887. On many motherboards that use the above type of Dallas RTC, the chip will be socketted and can be replaced easily. On some motherboards, the same type of chip will be soldered on. In such cases, the chip should be replaced only be a qualified technician. This will require removing the motherboard, carefully removing the soldered-on RTC, soldering on the new RTC (or a socket), and replacing the motherboard. This may be a costly job and should only be done in cases where it is deemed necessary.

 

[edfair]

Suspicions confirmed. Designer choice. My choice would be the replacable battery.
Replacement of a Dallas soldered in chip would cost more than a new M/B. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[fenix]

Hi Ed, yeah , the days of the soldering iron are getting shorter these days-kind of what happened to shoe cobbling, and fixing things in general.