1
00:00:00,433 --> 00:00:04,300
In this lesson, we will talk about how to repair no trigger fault
2
00:00:04,933 --> 00:00:09,233
We talked about the power button earlier, the Xiaomi phone is 1.8 volts
3
00:00:10,100 --> 00:00:13,300
What should we do when we can't measure its power button voltage?
4
00:00:13,566 --> 00:00:17,533
To check the circuit, it is because the power supply does not give it voltage
5
00:00:17,800 --> 00:00:22,100
Under what circumstances can the power supply give this 1.8 volts?
6
00:00:22,666 --> 00:00:26,100
When the main power supply is normal and the power chip is normal,
7
00:00:26,566 --> 00:00:30,466
it can only give a voltage of 1.8 volts to the power-on signal
8
00:00:35,400 --> 00:00:38,966
When we can't measure the 1.8 volts, we have to look back
9
00:00:39,800 --> 00:00:43,833
See if there is a problem with the power supply or the main power supply
10
00:00:44,333 --> 00:00:46,466
If the main power supply has no voltage,
11
00:00:46,700 --> 00:00:50,066
this 1.8 volt is definitely not available
12
00:00:50,500 --> 00:00:54,166
If the main power supply has voltage, the power chip does not work,
13
00:00:54,833 --> 00:00:59,633
and there is a fault, it cannot output 1.8 volts to power button signal
14
00:01:01,333 --> 00:01:03,900
Well, this is what makes the 1.8 volts
15
00:01:05,233 --> 00:01:08,400
So, the same is true for Huawei's power-on button
16
00:01:13,033 --> 00:01:16,533
How did the 1.8 volts on the power-on signal come from?
17
00:01:17,000 --> 00:01:22,000
Because of this 100K resistor and the 1.8V voltage on the left,
18
00:01:22,600 --> 00:01:26,433
there is only a 1.8V voltage on the power-on signal
19
00:01:30,000 --> 00:01:32,866
When we can't measure the voltage of 1.8 volts,
20
00:01:33,200 --> 00:01:38,166
we have to check here, let's see if there is no voltage of 1.8 volts here
21
00:01:38,433 --> 00:01:41,633
If the 1.8 volts power supply on the left is OK,
22
00:01:42,066 --> 00:01:44,433
and we can't measure 1.8 volts here,
23
00:01:44,966 --> 00:01:47,766
there is a problem with the 100K resistor,
24
00:01:48,200 --> 00:01:50,433
we can solve it by replacing it
25
00:01:52,366 --> 00:01:55,366
In the case that the power-on signal is not short-circuited,
26
00:01:55,966 --> 00:01:59,700
if the voltage of 1.8 volts cannot be measured here,
27
00:02:00,200 --> 00:02:04,233
then there must be no 1.8 volts on the power-on button signal
28
00:02:04,533 --> 00:02:10,366
When the power supply VOUT_PMUD on the left has no voltage, how do we find it?
29
00:02:11,266 --> 00:02:15,333
According to its working principle, it relies on this main power supply,
30
00:02:15,766 --> 00:02:17,633
the main power supply must be normal,
31
00:02:18,266 --> 00:02:24,033
and the power supply chip must be normal, so that it can output VOUT_PMUD
32
00:02:39,700 --> 00:02:42,333
If there is no voltage on the power button signal,
33
00:02:43,400 --> 00:02:46,466
there will be no response when we press the power button,
34
00:02:47,000 --> 00:02:49,333
When we can't measure 1.8 volts here,
35
00:02:49,633 --> 00:02:52,800
we must first test whether the main power supply is normal
36
00:02:53,800 --> 00:02:57,933
If the voltage on the main power supply is about 4 volts, it is normal
37
00:02:58,266 --> 00:03:00,266
Then there is no voltage here,
38
00:03:00,666 --> 00:03:03,500
then we have to suspect whether the power chip is damaged,
39
00:03:03,633 --> 00:03:05,800
or whether the power chip has been touched
40
00:03:06,733 --> 00:03:09,500
If it's been moved, we'll have to re-solder
41
00:03:09,866 --> 00:03:11,933
If the fault remains after re-soldering,
42
00:03:12,100 --> 00:03:14,000
then we need to replace the power chip
43
00:03:15,566 --> 00:03:20,133
Well, this is the working principle of 1.8 volts on Huawei's power-on button,
44
00:03:20,633 --> 00:03:23,066
and how should we troubleshoot if there is a problem
45
00:03:23,966 --> 00:03:28,666
The working principle of the power button signal of Oppo mobile phone is like this
46
00:03:29,033 --> 00:03:34,833
Its battery power goes directly through a 100K resistor to the power button signal
47
00:03:35,800 --> 00:03:39,866
Here is the shrapnel, generally we need to measure here when we measure
48
00:03:40,666 --> 00:03:43,633
If the power supply of 4 volts cannot be measured,
49
00:03:43,966 --> 00:03:48,700
it is related to whether there is a problem with the resistor R3001
50
00:03:49,166 --> 00:03:51,166
and whether there is false welding
51
00:03:52,333 --> 00:03:55,233
When we measure 4 volts on the right side of the resistor,
52
00:03:55,533 --> 00:03:57,033
but we can't measure it here,
53
00:03:57,500 --> 00:04:00,466
it means that there is something wrong with this resistor
54
00:04:01,566 --> 00:04:03,866
When we can't measure the voltage on the right side,
55
00:04:04,400 --> 00:04:05,733
we're going to look here
56
00:04:06,300 --> 00:04:08,466
If the voltage cannot be measured here,
57
00:04:08,766 --> 00:04:11,366
it means that the voltage cannot be measured here
58
00:04:11,800 --> 00:04:14,866
We need to see if the voltage at the battery terminal is normal
59
00:04:15,333 --> 00:04:18,633
If it is normal here and there is no voltage here,
60
00:04:19,200 --> 00:04:23,133
it can only be because the resistor R2802 is damaged,
61
00:04:23,700 --> 00:04:25,566
we will replace it directly
62
00:04:27,666 --> 00:04:33,100
100K to 220K pull-up resistors are generally used on the power button
63
00:04:33,733 --> 00:04:37,700
OK, here's how Oppo's power button works, and how to troubleshoot
64
00:04:39,500 --> 00:04:41,733
When there is no voltage on the power button,
65
00:04:42,200 --> 00:04:45,766
we need to see if the main power supply on the side of the power supply is normal
66
00:04:46,300 --> 00:04:48,966
If the main power supply has no 4V voltage,
67
00:04:49,466 --> 00:04:51,833
there must be no voltage on the power button
68
00:04:54,400 --> 00:04:56,133
Ok, that's it for this lesson
