1

00:00:01,766 --> 00:00:05,400

This lesson talks about the workflow of RF circuits

2

00:00:07,133 --> 00:00:10,200

The first part is the start of the baseband

3

00:00:10,766 --> 00:00:15,666

The baseband circuit is normal, and the radio frequency circuit can work

4

00:00:16,533 --> 00:00:19,366

How to check whether the baseband is normal?

5

00:00:20,233 --> 00:00:27,566

Enter *#06# on the dial interface, if the mobile phone displays IMEI and a set of numbers,

6

00:00:27,566 --> 00:00:31,500

it means that there is no problem with the baseband of the mobile phone

7

00:00:32,866 --> 00:00:35,333

If there is no problem with the baseband,

8

00:00:35,500 --> 00:00:40,566

it depends on whether the mobile phone can read the information of the number card normally

9

00:00:41,600 --> 00:00:45,666

Insert the number card, click "SIM card options" in the settings,

10

00:00:46,133 --> 00:00:50,966

and see if there are network operators such as China Mobile and China Unicom

11

00:00:53,633 --> 00:00:59,900

If the operator can be displayed, it means that the card reading circuit of the mobile phone is normal

12

00:01:01,733 --> 00:01:04,466

After there is no problem with the card reading,

13

00:01:04,466 --> 00:01:09,466

it depends on whether there is any problem with the receiving channel of the mobile phone

14

00:01:10,966 --> 00:01:15,033

Click on Cellular Data in Settings to find the carrier

15

00:01:18,333 --> 00:01:23,966

If the option of the operator is not grayed out, it needs to be changed to manual search

16

00:01:26,533 --> 00:01:29,400

If the network operator cannot be searched,

17

00:01:29,600 --> 00:01:34,066

it means that there is a problem with the receiving circuit of this mobile phone

18

00:01:34,566 --> 00:01:37,400

If there is a problem with the receiving circuit,

19

00:01:37,700 --> 00:01:40,800

it is necessary to repair the receiving channel

20

00:01:41,633 --> 00:01:44,400

If there is no problem with the receiving channel,

21

00:01:44,866 --> 00:01:49,266

it depends on whether the transmitting channel of the mobile phone is normal

22

00:01:50,666 --> 00:01:55,166

If the reception is normal, when the mobile phone has no signal or no service,

23

00:01:55,500 --> 00:02:01,166

it means that the transmitting circuit of the mobile phone is faulty, which leads to no service

24

00:02:02,600 --> 00:02:07,966

Here are the 4 steps to repair a no-service fault, these 4 steps cannot be confused,

25

00:02:08,233 --> 00:02:10,800

the baseband must be prioritized

26

00:02:12,900 --> 00:02:15,633

Only when there is no problem with the baseband,

27

00:02:15,966 --> 00:02:20,600

do you consider whether there is any abnormality in the circuit of the SIM card

28

00:02:21,000 --> 00:02:25,000

If there is no abnormality in the baseband and SIM card circuits,

29

00:02:25,000 --> 00:02:28,333

check whether there is any problem with the receiving channel

30

00:02:28,966 --> 00:02:31,633

When there is no problem with the receiving channel,

31

00:02:31,866 --> 00:02:37,200

but the mobile phone has no service, it must be that the transmitting circuit is faulty

32

00:02:38,633 --> 00:02:41,733

This is the workflow of the RF circuit

33

00:02:43,366 --> 00:02:45,266

That's all for this lesson