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Thread ID: 31513 2003-03-24 10:49:00 cmos battery BobM (1138) Press F1
Post ID Timestamp Content User
130491 2003-03-24 10:49:00 I wish to check the voltage on my cmos battery. I have found on my MOB a 30mmx15mm rectangular thingy with a white dot in one corner with <ODIN OEC 12C887A > marked on it, would this be it.? I will have to dislodge the board to get at the terminals so I want to be sure I have the right component. What should the voltage be.? BobM (1138)
130492 2003-03-24 10:56:00 Onless my failing memory has given up, thats a "dallas" type cmos RAM/battery combo thats not a replaceable item. Must be an old motherboard?

Cant remeber if the volts actually came to any pin to be measured, as its actually the CMOS chip with a battery encapsulated?
godfather (25)
130493 2003-03-24 10:57:00 Ah no, thats actually the CMOS IC itself. Either it is a silverdisc like object like a 10cent coin, or it is a plastic rectangle with red&black wires coming from it to the motherboard. Or, just to mind, a cylindrical object laying down horizontally, about the size of 3/4 of an AA battery. Any of those descriptions fit? Pheonix (280)
130494 2003-03-24 11:02:00 There is more info on these chips and their replacement here (www.firmware.com). Its a Real Time Clock CMOS chip with NON REPLACEABLE lithium battery encapsulated.

They discontinued that practice some time ago, thank goodness.
godfather (25)
130495 2003-03-24 11:06:00 Yes it is a few years old with a 233mmx cpu. It is a black plastic rectangular unit with no wires visible and approx. 4mm thick from memory BobM (1138)
130496 2003-03-24 11:11:00 It is a TMC A15TV Pent. 430VX MOB BobM (1138)
130497 2003-03-24 11:16:00 you may need to search the web for a source of a replacement RTC battery combo CMOS chip. Not a "user serviceable item" godfather (25)
130498 2003-03-24 11:36:00 Well I guess the voltage cannot be checked. the reason for the check stems from the fact that every couple of months on start up the computer boots as if I have just installed windows for the first time.All the settings I have changed revert back to original and outlook express and internet exp. have to be redone. Add/remove is empty although the programs are still there. I have run Windows over the top but the problem still occurs. BobM (1138)
130499 2003-03-25 06:49:00 If that battery was dead, you would be losing the BIOS settings, and (probably) date and time information. Is that happening? If not, I'd suspect Windows misbehaviour. :D

At least IBM put those packages in sockets when they used them, so they could be replaced. I don't like the idea of unsoldering DIL packages from multilayer boards.
Graham L (2)
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