1
00:00:00,666 --> 00:00:05,066
In this lesson, we talk about how to find the power supply of the CPU in the bitmap
2
00:00:07,800 --> 00:00:12,433
There is also a power chip on the CPU side, U4700
3
00:00:12,833 --> 00:00:16,066
The power it outputs can be found around this power chip
4
00:00:18,066 --> 00:00:21,800
For example, we look for the large inductor next to it
5
00:00:22,233 --> 00:00:25,566
One end of this large inductor is connected to the power chip,
6
00:00:26,000 --> 00:00:29,300
and the other end is connected to the U3100
7
00:00:29,733 --> 00:00:35,466
U3100 is a CPU, then this line is the power supply of the CPU
8
00:00:36,100 --> 00:00:38,133
Then let's look at another inductor
9
00:00:38,533 --> 00:00:43,466
One end of this inductor is connected to the power chip U4700,
10
00:00:43,666 --> 00:00:46,100
and the other end is connected to the CPU
11
00:00:46,366 --> 00:00:48,866
Then, this is also the CPU power supply
12
00:00:49,733 --> 00:00:51,733
Let's look at the inductors below it
13
00:00:52,266 --> 00:00:56,666
The upper end of this inductor is connected to the U4700,
14
00:00:56,933 --> 00:01:00,066
and its second pin is directly connected to the CPU
15
00:01:00,966 --> 00:01:03,500
That way it is also CPU power supply
16
00:01:04,966 --> 00:01:09,366
One end of this inductor L4802 is connected to the power supply,
17
00:01:09,933 --> 00:01:12,433
and the other end is connected to the CPU,
18
00:01:12,966 --> 00:01:15,700
so this line is also the CPU power supply
19
00:01:16,366 --> 00:01:18,633
Let's look at the following two inductors
20
00:01:19,000 --> 00:01:23,766
They are all connected to the power chip at one end and the CPU at the other end,
21
00:01:24,133 --> 00:01:26,433
which are also the power supplies of the CPU
22
00:01:28,333 --> 00:01:31,933
The above inductor, one end is connected to the power chip,
23
00:01:32,233 --> 00:01:34,633
and the other end is connected to other chips,
24
00:01:34,933 --> 00:01:41,100
for example, it leads to U7302, and U2400
25
00:01:41,633 --> 00:01:43,866
Of course, these are not CPUs,
26
00:01:44,100 --> 00:01:47,200
so this way of power supply is not CPU power supply
27
00:01:48,733 --> 00:01:50,633
Well, by directly checking the bitmap,
28
00:01:50,866 --> 00:01:54,366
we can quickly find out what the power supply of the CPU is
29
00:01:56,533 --> 00:01:59,900
When repairing, we usually look at the bitmap
30
00:02:00,366 --> 00:02:03,400
The bitmap can quickly find the location of its power supply
31
00:02:06,300 --> 00:02:09,233
For example, it is the power supply to the CPU,
32
00:02:09,466 --> 00:02:12,500
and there is a short circuit that caused the trigger protection
33
00:02:12,733 --> 00:02:14,100
Then when we test,
34
00:02:14,100 --> 00:02:18,166
we directly find which power supply is connected to the CPU
35
00:02:18,366 --> 00:02:23,700
For example, here, I found that the power supply is connected to the CPU,
36
00:02:24,400 --> 00:02:25,866
I doubt it,
37
00:02:26,900 --> 00:02:32,600
is it caused by the short circuit of the line VREG_S7C_0P6
38
00:02:33,166 --> 00:02:35,833
When measuring the ground value with a multimeter,
39
00:02:36,400 --> 00:02:37,933
if we measure the inductor,
40
00:02:38,366 --> 00:02:40,233
it is often difficult to measure,
41
00:02:40,700 --> 00:02:43,666
because the pins of the inductor do not extend outward
42
00:02:45,100 --> 00:02:50,266
It can be measured on the pin where one end of the capacitor above this line is not grounded
43
00:02:50,733 --> 00:02:54,533
The value measured by the diode gear of the multimeter is 0,
44
00:02:55,033 --> 00:02:58,033
which proves that this line has a short circuit to ground,
45
00:02:59,000 --> 00:03:01,833
then this line has caused the trigger protection
46
00:03:02,766 --> 00:03:06,866
This is a quick search method for the CPU and the temporary storage power supply
47
00:03:07,700 --> 00:03:10,800
Let's summarize, there are these steps
48
00:03:11,433 --> 00:03:13,366
First, find a power source
49
00:03:13,900 --> 00:03:16,900
Second, the large inductor around the power supply,
50
00:03:18,200 --> 00:03:21,533
click the two ends of the inductor directly on the large inductor
51
00:03:24,133 --> 00:03:26,666
The characteristic of the large inductor is that
52
00:03:26,666 --> 00:03:28,633
one end is connected to the power supply,
53
00:03:30,033 --> 00:03:32,266
and the other end is connected to the CPU
54
00:03:40,700 --> 00:03:45,500
This large inductor is actually a step-down circuit, which is BUCK,
55
00:03:46,166 --> 00:03:48,666
its power supply is connected to the CPU
56
00:03:50,566 --> 00:03:53,066
Let's not forget we're looking for the power supply
57
00:03:53,500 --> 00:03:56,366
Xiaomi's power supply code is VREG,
58
00:03:56,666 --> 00:04:00,033
we will learn the power supply code VBUCK later
59
00:04:01,066 --> 00:04:04,500
Start with VREG, start with VBUCK,
60
00:04:05,300 --> 00:04:07,033
these are the power supplies
61
00:04:08,166 --> 00:04:11,933
What we are looking for is the power output from the power supply to the CPU
62
00:04:12,266 --> 00:04:16,466
First of all, what is the beginning of the power supply we need to know
63
00:04:17,666 --> 00:04:19,900
Second, where do we find?
64
00:04:20,266 --> 00:04:23,100
Look for the large inductor line around the power supply,
65
00:04:23,633 --> 00:04:26,433
we click it, it will be highlighted in yellow
66
00:04:26,900 --> 00:04:28,700
Ok, that's it for this lesson
