IS THERE A BATTERY PRESENT IN MY MACHINE? WHY IS A BATTERY NEEDED FOR? WHY DOES ROM NEED POWER FOR? I THOUGHT THAT DATA IS RESIDENT ON IT. COULD IT BE LOST WITHOUT THE BATTERY? HOW LONG DOES A BATTERY LAST? WHEN SHOULD I REPLACE IT? IS THERE A WAY TO KNOW? THE BATTERY NEEDS TO BE REPLACED. HOW CAN I LOCATE IT? IS IT A COMMON ONE? I FOUND THE BATTERY. HOW CAN I REPLACE IT?
IS THERE A BATTERY PRESENT IN MY MACHINE?
Yes, there is. Every single Computer has a battery installed. In fact, the battery is an integrated part of the motherboard.
A battery is needed to supply the ROM (Read Only Memory) with constant power, when the machine is not turned on.
No. The data cannot be lost without the battery, or when it is getting weak. ROM needs the battery for the settings stored by the user. For example, the system time and date, the memory settings etc. The main programs (BIOS, POST commands etc.) are resident on the ROM and cannot be erased by just removing the battery.
It depends on its type. Most of them last for about three to four years. Others may last even longer.
WHEN SHOULD I REPLACE IT? IS THERE A WAY TO KNOW?
Almost every time a battery gets weak, the system shows an error message during the Boot Procedure: “CMOS Checksum Error. Defaults Loaded”. This means that a problem was detected by the POST (Power On Self Test), so the default BIOS settings were loaded to maintain the best possible system performance. Most of the times, this is caused by a weak battery.
THE BATTERY NEEDS TO BE REPLACED. HOW CAN I LOCATE IT? IS IT A COMMON ONE?
There are various battery types for Computers:
TYPE 1
This is the most common one. CR2032, Lithium Cell.
TYPE 2
Common on older 286/386/486-based systems.
Barrel-type, 3.6V/60mAh
TYPE 3
Found on some older 486/586/686-based systems.
ODIN box. This little black box has twenty pins and it is placed on a special socket on the Motherboard, just like the common ICs (Integrated circuits).
TYPE 4
External one. This is a battery in a box having two pins (Positive and Negative pole) which are connected to the Motherboard via two cables. Red (Positive) and Black (Negative). In order to do that, an external battery connector must be available on the Motherboard.
I FOUND THE BATTERY. HOW CAN I REPLACE IT?
A wise thing to do, is to write down or print the settings loaded on the BIOS. When the battery gets weak those settings will be lost and the defaults will be loaded. Even when you replace a battery, those settings will be lost too.
Some times, it could be difficult for an end-user to set the BIOS back correctly.
To print those settings, enter the BIOS, turn on the printer and press the “Print Screen” key on your keyboard.
TYPE 1, CR2032, Lithium Cell:
You can use a pocket-sized screwdriver to take this type of battery off the Motherboard. This is very easy thing to do, but be careful not to scratch the Motherboard if the screwdriver accidentally slips from the battery. Then put the new one. The positive pole should be on the top and you should be able to read what is written on the cell.
TYPE 2, Barrel-type, 3.6V/60mAh:
Things are more complicated about this type, because it is soldered on the motherboard.
There are two ways to replace it. Each one uses a different type of battery.
1. Take the Motherboard off the case and disconnect the battery from the back side of the Motherboard using a soldering iron. Then put a new one (TYPE 2, Barrel-type, 3.6V/60mAh) on and solder it. Be careful with the positive (+) and the negative (-) pin. Don't sold them backwards! The correct side is printed on both the Motherboard and the battery.
2. This is an easier way. Check on the Motherboard's manual or the Motherboard itself if there is an external battery connector. If so, you do not need to take the old battery out. Just connect an external one (described as Type 4). Be careful with the positive (+) and the negative(-) pin too! Also, check if there is a jumper that cuts off the battery on board for the use of the external one. Most of the times, there is not such jumper.
TYPE 3, ODIN box:
Use a pocket-sized screwdriver to pull it out. First the one side, then the other.
Then put the new one on and press it gently.