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cmos battery holder problem

moltoncore

Mar 30, 2019
2
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Mar 30, 2019
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I am working on an Acer laptop motherboard which has a detached cmos battery holder... Not only that, but the pads are pretty gone. the negative pad can be soldered to, but I can't find the positive pad or where to solder the positive part of the holder. Any tips on where to solder a wire perhaps...?

thx
 

Martaine2005

May 12, 2015
4,274
Joined
May 12, 2015
Messages
4,274
If you are using the original battery holder, it should be easy to see where the lifted pad was. Trace it back to nearest component leg or scrape away the masking on the copper trace and solder a jumper wire. Make sure you glue the battery holder in place as only one solder joint (negative), will be a weak spot.
If you have problems, take clear photos of both sides of the board and post them here. Somebody will be able to help you.

Martin
 

moltoncore

Mar 30, 2019
2
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Mar 30, 2019
Messages
2
Would this work? positive connected to + cmos jumper or the second image?
 

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Martaine2005

May 12, 2015
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To be perfectly honest, I wouldn’t like to say.
But, there should be no need to guess!. The positive (missing) pad would have been part of a trace next to the positive side of the battery holder. It may go through a via to the underside of the board. If it’s a multi-layer board, you will need a schematic. BUT, if only the pad is lifted/missing, the connection you require will be millimetres away from the positive side. Use a magnifying glass and you will see where the pad was originally part of a (now) broken trace. It should be fairly obvious.
You will have to remove that green wire and clean that area up to be able to see properly.

Martin
 
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