Basic knowledge of mobile phone maintenance

Before carrying out mobile phone maintenance, we must first understand some basic concepts.

First, turn it on.

Booting refers to the process that the mobile phone enters the power-on self-test and network search after the power is turned on and the on/off key of the mobile phone is pressed for about 2 seconds. When the logic part functions normally, the display screen starts to display all kinds of prompt information until the signal strength and battery power are finally displayed, some mobile phones display signals such as time and network, and the network access indicator turns green and flashes continuously. After a few seconds, the backlight goes out.

Second, turn it off.

Reverse the power-on process. After pressing the ON/OFF key for 2 seconds, the mobile phone enters the power-off procedure. After that, there is no display information on the screen of the mobile phone, and the network access sign and background light are all extinguished.

Third, the working state.

In maintenance, it is often said that the mobile phone is in working state, which means that the mobile phone is in receiving or transmitting state (when the mobile phone is set to test state, the mobile phone can be in receiving or transmitting state alone).

Fourth, standby state

The mobile phone is not in use, but it has been on.

Verb (abbreviation for verb) power failure

After the phone is turned on, it will automatically turn off without pressing the on/off key, sometimes it is also called power off, also called automatic power off or automatic power off.

VI. Leakage

If the mobile phone is not turned on after adding DC regulated power supply, the pointer of the ammeter will have current indication. Under normal circumstances, the indicated value of ammeter is 0mA.

Seven, the mobile phone shows weak current

Install a newly charged battery on the mobile phone. After the mobile phone is turned on, the user is prompted that the battery voltage is not enough, and the battery indicator light on the display screen keeps flashing and gives an alarm sound. This phenomenon is called that the mobile phone displays weak current.

Eight, don't access the network.

The fact that the mobile phone is not connected to the Internet means that the mobile phone cannot access the GSM network, that is, there is no network information and no indication of the signal strength value on the display screen of the mobile phone. Under normal circumstances, after the mobile phone is connected to the network, the network name is displayed on the display screen, and the network access indicator light flashes green. If there is no network, the network indicator flashes red, so it is also called no network and no turn signal.

Nine, put down the signal.

Signal loss means that the signal strength on the display screen of the mobile phone changes greatly, for example, from 5 grids to 2 grids, and 1 grid to 5 grids. This phenomenon is also called signal instability. When the mobile phone presses the transmit key, the signal strength value becomes zero or changes greatly. This phenomenon is called signaling.

X. virtual welding

Refers to the poor contact between the component pins in the mobile phone and the solder joints of the printed circuit board.

XI。 weld

The method of re-welding or re-welding a little tin on the pin of the component is called repair welding, sometimes called strengthening welding.

Twelve, insert the card

Inserting a SIM card into the card holder is called inserting a card.

Thirteen, don't know the card

Refers to the mobile phone can't read the information on the card, and the mobile phone prompts the card insertion or check card information on the screen.