Keyboard is a primary input device of the PC. It is used to enter commands and type text. The keyboards are similar to the type writers but have additional keys. There are several keys on the keyboard including the alphabets and the numbers. The different type of keys is:
- Alphanumeric: Enables the user to enter text and numbers.
- Punctuation: Enables the user to punctuate sentences and additional characters.
- Navigation: Used to move the cursor between different places on a screen.
- Special: Perform some special functions on the data.
- Windows: Open windows-specific items like the start menu.
- Function: Used to perform certain functions like provide help.
- Numeric: Enables the user to perform numerical operations on the data.
- Modification: Enables the user to use additional features like capitalizing letters.
Working of a Keyboard
The computer keyboard has a microprocessor that studies the state of each key on the keyboard and sends the appropriate signal to the computer. There is arid of circuits underneath the keys on the keyboard. It is known as the key matrix. When you press a key, the circuit is closed and the current flows. The microprocessor detects the closed circuit and notes the position of the circuit on the key matrix. The microprocessor has a character map of the keyboard in its ROM. It compares the location of the closed circuit to the same location in the character map. The character map is the comparison chart that tells the microprocessor which key is present at a particular location. If you press a combination of characters, the keyboard processor compares the combination to the character map to see if there is any designation for that particular combination. The keyboard processor analyses the key matrix and decides on the characters to be sent to the computer. These characters are maintained in a memory buffer and then sent in a stream to the computer. The data stream is then sent through a connector that connects the keyboard to the computer.
Troubleshooting a keyboard
The keyboard must be handled with a lot of care. You must not spill liquids or food particles on the keyboard. However, the keyboard is largely a trouble-free device if handled properly.
Computer displays keyboard error:
- Check if the keyboard is connected properly to the computer.
- Check connector pins and see if any pin is absent.
- Turn the keyboard over and hit gently to dislodge any dirt or pin stuck beneath the keys.
- Properly reconnect the keyboard. Ensure that no key is pressed or stuck when the system is starting up.
- If the keyboard does not work, connect the keyboard to another computer and see if it works.
- If still the keyboard does not work, check the port and connector which is connected from keyboard controller on the motherboard to the port to check for loose connections or damage.
- If the keyboard controller is damaged, you may have to replace the keyboard controller or the entire motherboard.
Keyboard does not operate properly:
- If the keys on the keyboard seem sticky, it is possible that the keyboard is dirty. If you eat or drink around the computer, you may drop substances onto the keyboard.
- You can clean the keyboard by blowing compressed air under the keys. This will remove the dry particles stuck underneath. This will also dry any split liquid.
- If you split any sticky liquid on the keyboard, compressed air will not help much. In this case, the best option is to remove one key at a time and clean underneath.