【 Weak current college 】 computer hardware malfunction surf 2---Power By 【 China power house network 】

★ Computer failure of keyboard story ★

The keyboard is in use, the failure of manifestations is varied, the reasons are manifold. There is a failure, poor contact with key itself mechanical failure, there is a logic circuit failure, soldered and welded, unsoldering and oxidation of metal hole. maintenance such as fault according to the different symptoms for analysis, identify any trouble, make the appropriate repairs.

A common fault: some keys on the keyboard, such as the space bar or enter key does not work, sometimes required to enter only as many times — one or two characters, some of the key, such as the cursor key down once to move the cursor on the screen, keyboard consecutive characters cannot enter, then you can play at a time.

This failure to keyboard "card key" fault, just use the old keyboard for a long time, some useless soon new keyboard, keyboard card key failures sometimes occur. A keyboard card key phenomenon mainly consists of the following two reasons: one reason is the keycap following plug column position offset, keycap press and key body shell stuck can't up and created a card key, this occurred in a new keyboard or using the near key on the keyboard. Another reason is to press the reset after long use spring to become very poor, shrapnel and larger by Rod friction, you cannot leave the keys up the card key, this occurred in long-term use of the keyboard. Occurs when a keyboard key fault, the card will disconnect the keycap, and then press the lever. By rod up or weak, are the second causes, or as the first reasons. If as a result of the keycap and key body shell stuck cause trouble "card keys" are also available at the keycap and keys put a spacer between the gasket available some slightly hard plastic (such as obsolete floppy-coat), its size is equal to or slightly greater than the key body size and location of the bar by opening a can of ammonium-free through the square hole, it is set in the bar, plug in the keycap;use this spacer block key caps and a key body stuck, you can fix issues press; if it is due to the spring fatigue, spring resistance larger causes card key failure, then you can open a special key body, slightly stretch back spring back elasticity; remove the spring will be key in recovery. By removing the shrapnel, reducing the resistance by rod up so that failures have been resumed. keys

Common fault II: some characters cannot be entered.

If only one of the key characters cannot be entered, you may be the key failure or deficiency of welding solder joints. Checks, in accordance with the method described above to open the keyboard, using a multimeter measuring junction resistive stalls on-off State. If the key pressed is always on, then press the Reed fatigue or bad, needs to be repaired or replaced; if the key pressed contact switching in normal, may be due to deficiency of welding, unsoldering or gold dust hole caused by oxidation, can be measured along the printing line-by-paragraph, find fault with heavy welding; as a result of any failure of metal oxidation and holes, you can clean the oxide layer, and then welded solid; if metal hole completely off the circuit breaker, plus welding wire to connect.

Three common fault: If there are multiple neither in the same column, they are not in the same row of keys will not be able to enter.

May is the column or row lines of a circuit breaker, or may be a logic gate circuit failure. At this moment available 100-frequency oscilloscope for fault detection, identified, and then the virtual devices to repair solder joints.

Four common fault: keyboard input and display the characters do not match.

This kind of failure may be due to a phenomenon produced short circuit on the Board, its performance is based on this key are displayed for the same column of the other characters, you can use to measure a multimeter or oscilloscope, determine whether the failure point after the repair.

Five common fault: press a key to produce a string of wide characters, or bounce when characters.

This behavior is caused by a logic circuit fault. Select a column character, if not enter a column in a row, it is possible to have multiple other characters; if the column containing the Enter key will produce characters bounce and finally enter the system, use the oscilloscope check logic circuit chip, find fault with the models after replacement of the chip's new chip, troubleshooting.