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Old August 21st 20, 12:41 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
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Posts: 11,873
Default Image of Bottom of Motherboard, HP Pavilion XT155 laptop

J. P. Gilliver (John) wrote:
On Thu, 20 Aug 2020 at 13:11:04, wrote:
[]
With the battery removed, I am going to wait 24 hours or more for
CMOS
memory to clear (did that on other HP laptop years ago). I measured the


You could short the cell terminals (e. g. put in a coin rather than a
coin cell!) on the mobo once you've removed the cell, which would
probably clear/reset it sooner. (With no power - mains or battery -
connected of course! And remember to remove the short/coin before
applying any power!)
[]


Which includes removing the wall adapter, the main battery pack,
the coin cell, *then* short out the socket as a means to
drain the last remaining supply (a tiny ceramic cap sitting
on the VBAT line). The purpose of the tiny ceramic cap is
to provide instantaneous current when a counter ticks
in the RTC well.

You should not short out the coin cell socket while power
is available. There is a charging circuit connected to the
coin cell, and we don't want to be shorting that out
while it's attempting to charge the cell. With all power
removed, it won't be attempting anything.

I'm expecting, if it is an LR20xx or ML20xx rechargeable cell,
that's not going to be available at the watch repair store
(a supplier of batteries). I don't even know if the Geek Squad
would have something like that. Locating one should be more
annoying than finding a CR20xx.

Paul
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