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Thread ID: 22175 2002-07-13 23:41:00 Clock Mick (1021) Press F1
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62276 2002-07-13 23:41:00 I have a 1.7 Pentium 4 with a Transcend TS-ABD4 and Windows XP Home Edition. The computer is less than 1 yr old and I have taken it back to the shop twice but they say it runs perfectly okay. Do XP have chips or batteries to run the clock?
I have checked the CMOS and the time zone which I correct when I switch the machine on but overnight when I turn off the clock goes completely haywire and if I leave the machine running the clock maintains the right time.
Hope you can help.
Mick
Mick (1021)
62277 2002-07-14 00:02:00 Its not XP that has the function, but the CMOS Real Time Clock on the motherboard.

Yes, they have a battery, usually a CR2032 or similar on most motherboards these days. About $5 at supermarket battery stands.

They look about the size of a 10 - cent piece, and can fail prematurely but usually last many years. They are a lithium cell, like an overgrown watch battery
godfather (25)
62278 2002-07-14 03:54:00 The computer will have an ATX power supply, which when "turned off" with the front panel "power switch) will maintain the CMOS clock regardless of the battery condition. There is a line called 5VSB which is always on. This operates the "Power switch" and any "Wakeup" devices). That is probably what fooled the shop (though they should know this ;-) ). If you actually turn it off at the wall, or unplug the computer, that will make it rely on the battery.

Any operating system reads the CMOS clock when it starts up. After that, it uses the 18.2 ticks/second interrupt provided by the BIOS.

I would change the battery.
Graham L (2)
62279 2002-07-14 06:45:00 Thanks for the help

mick
Mick (1021)
62280 2002-07-14 06:47:00 Thanks for the help

Mick
Mick (1021)
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