Laptop losing its CMOS Settings


We have a Novatech W950LU laptop which has served us well until recently. Now whenever it is switched on, after it has been disconnected from the mains, it wont boot without going into the CMOS and setting up the boot order.

Because it is ok if the laptop remains connected to the mains, I am wondering if this is a laptop battery issue rather than a CMOS battery issue… And what part no we need buy to resolve it?



This sounds exactly like CMOS battery has run flat. System mainboard will use AC Power standby to maintain BIOS function rather than CMOS battery when AC is present in order to extend the life of the CMOS battery. Lose of settings after AC power has been removed would indicate the need for a new CMOS battery.

As for issues regarding the laptop battery, does your battery currently hold charge, do you get any useful life out of it??

The laptop battery is effectively dead - for the most part the laptop has been connected to the mains when it has been used throughout its life.

Would replacing the laptop battery (which I am guessing is easier than replacing the CMOS battery) resolve the issue?




No replacing the main battery would not support BIOS Setting function. CMOS is only preserved via CMOS Battery and AC mains. It does not get power from the main battery. As such replacing the main battery would not help in this situation.
Depending on how confident you are dismantling electronics, the process to replace the CMOS battery is not that difficult or time consuming on the W950LU.

Thanks COOPS

Any idea what the CMOS battery is?


Its just a standard CR2032 Coin cell located next to the DIMM Slot.

If you refer to the service manual. You can see it in the mainboard photos and also information can be found on how to remove the rear access panel to gain access to the battery holder


Just wanted to say thanks COOPS its all sorted now, having replaced the CMOS battery


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