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Dead cmos battery work around, old socket 7 pc.

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March 11, 2013 1:02:50 AM

I recently decided to tryout my old socket 7, Pentium 1 PC. Thought it turns on perfect and displays (18 years old) i always get a low cmos battery error and it forces me to go to bios, which every time i set something and save it, it does not because the battery is dead . So i looked inside the PC, and to my surprise, the battery is not like every other PC , it is a black rectangle soldered to the board. Is there anyway i can use an external battery thru any pins or is there another type of work around?
Here is the link to images of it.

http://imageshack.us/g/443/20130310224736.jpg/
a c 400 V Motherboard
March 15, 2013 8:25:06 PM

I can't believe any manufacturer would solder a battery to the board, unless it was re-chargeable. What board is that? I still don't see the battery you mention.
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a b V Motherboard
March 16, 2013 9:18:12 AM

Your motherboard is using the M48T86PC1 IC, a 5.0V PC Real Time Clock. The backup battery will be good for 10 years of data retention and clock operation in the absence of power. The backup battery is inside the IC, nothing can be done to replace the battery. You could replacement the IC with this one DS12887.
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a c 400 V Motherboard
March 16, 2013 9:49:46 AM

Now I see the battery! It says Lithium Battery right on it! Geez. Blind as a bat. :pt1cable: 
I'm still shocked that even as recently as the 486/Pentium days they would still have used a soldered-in chip w/battery, but Jarotech is undoubtedly correct.
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March 16, 2013 1:10:58 PM

jarotech said:
Your motherboard is using the M48T86PC1 IC, a 5.0V PC Real Time Clock. The backup battery will be good for 10 years of data retention and clock operation in the absence of power. The backup battery is inside the IC, nothing can be done to replace the battery. You could replacement the IC with this one DS12887.
yep I found a 24 pin clock battery on ebay of the same make for 7.00 $, anyway Is there anyway i can remove the old ic and solder this one in? I know a guy who experienced in soldering.

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a b V Motherboard
March 16, 2013 1:17:33 PM

Just desolder the ic, take it out, put the new one in the holes and solder the pins, that's it.
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