Teach you to analyze the reasons for the failure of the keyboard and the solution

The old saying is: "There is a gloom in the moon, people have a good fortune", every thing has its life, can not be forced. The keyboard is an important input device in the process of using the computer. It will also have problems one day, and the computer will lose the function of truly interacting with people. This not only requires the keyboard to fail frequently, but also requires accurate and sensitive keyboard input, so that the computer really obeys us, rather than letting it bother us. In this case, what are the reasons for the keyboard failure, and how to solve it. Let us take a look at it now:

Common fault one: Some keys on the keyboard, such as the space bar, the Enter key do not work, sometimes, you need to enter — or two characters, innumerable times, Some keys, such as the cursor key, no longer rise after pressing, the cursor on the screen moves continuously. At this time, other characters of the keyboard cannot be input, and you need to press again to play it.

This kind of fault is the "key" of the keyboard. It is not only the old keyboard that has been used for a long time, but also the new keyboard that has not been used for a long time. The keyboard key failure sometimes occurs. The card key phenomenon of the keyboard is mainly caused by the following two reasons: One reason is that the position of the post under the key cap is offset, so that the key cap is stuck with the key body casing and cannot be bounced, thereby causing the card key. This reason mostly occurs on new keyboards or keyboards that are used very soon. Another reason is that after the button is used for a long time, the spring elasticity of the return spring becomes very poor, and the friction between the spring and the push rod becomes large, and the button cannot be bounced to cause a card key. This reason often occurs on the keyboard that is used for a long time. When the keyboard has a card key failure, you can lower the keycap and press the lever. If the bullet does not move up or is weak, it is caused by the second cause, otherwise it is caused by the first cause. If the key is stuck due to the keycap and the key body casing, the card key may be placed between the keycap and the key body. The gasket may be a slightly harder plastic (such as a discarded floppy disk). The outer casing is made to have a size equal to or slightly larger than the size of the key body, and a square hole through which the ammonium rod can pass freely is opened at the position where the rod is passed, and the keyhole is inserted after the rod is pressed, and the key cap is inserted; The gasket prevents the keycap from being stuck with the key body, and the faulty button can be repaired; if the spring is fatigued, the resistance of the spring is increased, causing the key to be broken. At this time, the special key body is opened, and the spring is slightly stretched to restore the elasticity. ; Remove the shrapnel to restore the key body. By removing the shrapnel, the resistance of the lever bounce is reduced, so that the faulty button is restored.

Common fault 2: Some characters cannot be entered.

If only one key character can't be input, it may be that the button is invalid or the solder joint is soldered. When checking, open the keyboard as described above and measure the on/off status of the contacts with the multimeter resistance file. If the button is not turned on when it is pressed, it indicates that the button reed is fatigued or has poor contact, and needs to be repaired or replaced. If the contact is turned on and off normally when the button is pressed, it may be due to soldering, desoldering or gold hole oxidation. Therefore, it can be measured piece by piece along the printed circuit to find out the fault for re-welding; if it fails due to oxidation of the metal hole, the oxide layer can be cleaned and then re-soldered; if the metal hole is completely detached and the circuit is broken, another Add solder leads for bonding.

Common Fault 3: If there are multiple buttons that are not in the same column or in the same row, you cannot enter them.

It may be that the column or line is disconnected somewhere, or the logic gate may be faulty. At this time, a 100MHz high-frequency oscilloscope can be used to detect the broken solder joints of the faulty device and then repair it.

Common Fault 4: The keyboard input is inconsistent with the characters displayed on the screen.

This type of fault may be caused by a short circuit on the board. It is displayed by pressing this button but it is displayed as other characters in the same column. At this time, the measurement can be performed with a multimeter or an oscilloscope to determine the fault point. Repair it.

Common Fault 5: Press a button to generate a string of characters, or jump characters when you press a button.

This phenomenon is caused by a logic circuit failure. First select a column of characters, if it is a column of a row without the Enter key, there may be a number of other characters phenomenon; if it is a column containing the Enter key, it will produce characters jumping and not entering the system finally, with The oscilloscope checks the logic circuit chip, finds the faulty chip, replaces the new chip of the same model, and eliminates the fault.

The above keyboard failures are generally associated with poor contact failure, mechanical failure of the button itself, logic circuit failure, virtual welding, false welding, desoldering and metal hole oxidation, so first find out when repairing The reason, then the right medicine, in order to effectively solve the problem.

Through these few tricks, I believe that your keyboard can be more "live" some time, but Xiaobian believes that cleaning and maintaining your keyboard is the best policy. Then is the last thing we want to say, that is to see how you manage your keyboard.