Knowledge Base

How to replace a CMOS battery.

Article Summary: Procedure to Replace a CMOS Battery
Article Summary: This article provides information about the procedure to replace a CMOS battery.

Procedure to Replace the CMOS Battery
Before performing any of the procedures in this section, read and follow the safety instructions in Dell Knowledge Base Article: "Precautionary Measures for Personal Safety" Article ID: 339031.
A new battery can explode if it is incorrectly installed. Replace the battery only with the same or equivalent type recommended by Alienware. Properly dispose of used batteries as required by the local authorities.

While prying the battery out of its socket with a blunt object, be careful not to touch the system board with the object. Ensure that the object is inserted between the battery and the socket before attempting to pry out the battery. Otherwise, the system board might be damaged by prying off the socket or by breaking circuit traces on the system board. To avoid damage to the battery connector, firmly support the connector while removing the battery.

When attempting to replace a CMOS battery for a laptop, please contact the Technical Support Department for further instructions. The procedure on this article applies only to desktop systems.
All full tower desktop computers use a 3 volt lithium battery also used on wrist watches and other small electronic devices. The flat side of the battery is always positive. The CMOS battery keeps the time and date, even if the computer is off and unplugged. A CMOS battery usually lasts two to three years.

There are two ways to replace the CMOS battery, which depends on the way it is positioned on the motherboard.
Method 1
  1. Open the computer case.
  2. On most motherboards, the battery holder lays flat on the board itself and has a small metal tab (Figure 1). Push this tab away from the center of the battery so it can pop up.
  3. To install the battery, press it on the battery holder keeping the positive (flat) side facing you.

Figure 1: Typical CMOS Battery Holder
Method 2
  1. Open the computer case.
  2. Some motherboards may have an angle-mounted battery holder, in order to save space on the motherboard's surface (Figure 2). In this case, hold the tab and pull the battery out and away from the motherboard.
  3. To install the battery, place it in the battery holder with the positive (flat) side facing up (the slot will hold the battery in one position only).

Figure 2: CMOS Battery Holder (Click on image to enlarge)

Article ID: SLN130418

Last Date Modified: 07/17/2017 03:44 PM

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