1

00:00:00,266 --> 00:00:02,566

Small current when iPhone is turned on

2

00:00:02,833 --> 00:00:07,766

In this lesson, we mainly explain how to query CPU working conditions

3

00:00:08,200 --> 00:00:13,066

The search method of CPU working conditions is suitable for all models of iPhone

4

00:00:13,966 --> 00:00:17,033

Let's first look at how to find the CPU power supply

5

00:00:18,933 --> 00:00:22,566

This search method is basically similar to the power supply search method

6

00:00:22,566 --> 00:00:25,533

for high current at startup and power output

7

00:00:27,233 --> 00:00:30,700

The only difference is that after it jumps to the bitmap,

8

00:00:31,966 --> 00:00:33,833

if the CPU turns yellow,

9

00:00:33,900 --> 00:00:36,300

it means that this power supply is for the CPU

10

00:00:38,200 --> 00:00:41,666

The power supply will output more than 30 channels of power supply

11

00:00:42,000 --> 00:00:43,600

When the CPU is working,

12

00:00:43,900 --> 00:00:47,266

it generally needs about 15 channels of power supplies

13

00:00:48,533 --> 00:00:51,866

Let me take the iPhone 12 model as an example to demonstrate

14

00:00:53,433 --> 00:00:58,933

First, we open the circuit diagram, bitmap and component map of the iPhone 12

15

00:01:01,833 --> 00:01:05,033

We find the position of the main power supply in the component map,

16

00:01:09,633 --> 00:01:13,033

and then find the number of the main power supply in the bitmap

17

00:01:16,400 --> 00:01:20,633

The power supply number of this iPhone 12 is U3300,

18

00:01:21,633 --> 00:01:24,800

we search for U3300 in the drawings

19

00:01:27,466 --> 00:01:31,166

After the search, there will be many boxes on the power supply,

20

00:01:32,233 --> 00:01:38,733

and the inside of the box marked with LDO or BUCK represents the power supply output by the power supply

21

00:01:40,166 --> 00:01:42,533

We don't need to search for other lines

22

00:01:44,000 --> 00:01:45,966

Let's look at the first box first

23

00:01:46,533 --> 00:01:51,433

The BUCK inside the power supply represents the power supply output of the power supply

24

00:01:52,100 --> 00:01:55,866

We jump to the bitmap according to the English logo behind the line

25

00:01:59,833 --> 00:02:02,700

If the color of the CPU turns yellow in the bitmap,

26

00:02:03,066 --> 00:02:07,566

it means that this power supply will provide the working voltage for the CPU

27

00:02:08,500 --> 00:02:11,333

Let's look at the second power supply according to the name

28

00:02:12,700 --> 00:02:15,433

This power supply also goes to the CPU

29

00:02:19,100 --> 00:02:21,666

This power supply is not connected to the CPU

30

00:02:22,066 --> 00:02:25,333

The CPU needs about 15 channels of power supply,

31

00:02:25,800 --> 00:02:28,900

and we have to jump to see each channel of power supply

32

00:02:31,000 --> 00:02:34,200

This power supply does not provide voltage for the CPU

33

00:02:35,666 --> 00:02:40,533

After starting up, we can go to the yellow point in the bitmap to measure the voltage

34

00:02:41,766 --> 00:02:43,533

If the voltage is abnormal,

35

00:02:43,766 --> 00:02:46,200

it means that there is a problem with the power supply

36

00:02:47,066 --> 00:02:51,066

Next, let's take a look at the CPU clock signal search method

37

00:02:52,100 --> 00:02:55,866

Open the circuit diagram, bitmap and component map of the model

38

00:02:57,666 --> 00:03:01,766

Search directly for 24M or 24.000 in the circuit diagram

39

00:03:05,666 --> 00:03:09,966

After searching, we can find the 24M crystal oscillator,

40

00:03:12,400 --> 00:03:15,633

and then jump to the bitmap to find the measurement point

41

00:03:18,633 --> 00:03:20,633

Let me demonstrate it below

42

00:03:21,833 --> 00:03:24,233

Let's take iPhone 12 as an example

43

00:03:25,066 --> 00:03:30,100

We search for 24M in bitmap and there are many search results in the list

44

00:03:33,433 --> 00:03:35,000

Let's start with the first one

45

00:03:39,600 --> 00:03:43,500

For example, if we search for 24M at this location,

46

00:03:43,733 --> 00:03:46,466

there will be a number Y1000 next to it,

47

00:03:46,900 --> 00:03:49,600

and Y represents the crystal oscillator

48

00:03:50,400 --> 00:03:55,633

It means that this Y1000 is the 24M crystal oscillator of the CPU

49

00:03:56,566 --> 00:04:03,166

After finding it, we can jump to the bitmap according to the pin English identification of the crystal oscillator

50

00:04:04,466 --> 00:04:07,400

The yellow point in the bitmap is the measurement point,

51

00:04:07,666 --> 00:04:09,200

we can measure the voltage

52

00:04:10,133 --> 00:04:12,666

We need to measure the voltage at both pins

53

00:04:13,466 --> 00:04:16,800

Let's take a look at the CPU reset signal search method

54

00:04:18,866 --> 00:04:23,366

Open the circuit diagram, bitmap and component map of the faulty model

55

00:04:23,566 --> 00:04:26,233

Search for COLD_RESET in the circuit diagram,

56

00:04:30,100 --> 00:04:33,066

this is suitable for models above 6S

57

00:04:34,433 --> 00:04:38,933

If it is an iPhone 6, search for RESET in the drawing

58

00:04:41,433 --> 00:04:45,166

After searching, if the English logo inside the CPU box

59

00:04:45,166 --> 00:04:47,166

is consistent with the current name,

60

00:04:47,566 --> 00:04:49,933

it means the reset signal of the CPU

61

00:04:52,566 --> 00:04:57,100

Then we can jump to the bitmap according to the corresponding English name outside the box

62

00:05:02,866 --> 00:05:07,333

We can measure the voltage and diode value of the reset signal on the yellow dot

63

00:05:09,700 --> 00:05:12,433

Let's take the iPhone 12 model as an example

64

00:05:13,066 --> 00:05:15,700

We searched for COLD_RESET in the drawings,

65

00:05:18,700 --> 00:05:23,366

and after searching, we found that the English names were the same,

66

00:05:23,733 --> 00:05:25,300

and they were inside the box

67

00:05:26,133 --> 00:05:28,500

U1000 refers to the CPU

68

00:05:29,466 --> 00:05:34,433

This pin is the reset of the CPU, the English name outside the box

69

00:05:36,066 --> 00:05:39,066

After selecting, jump to the bitmap,

70

00:05:41,366 --> 00:05:43,233

the position of the yellow point,

71

00:05:43,600 --> 00:05:46,000

we can measure the diode value and voltage

72

00:05:47,700 --> 00:05:49,766

Ok, that's it for this lesson