1

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Now we clean the motherboard

2

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After flattening the solder on the motherboard, don't rush to clean the soldering oil

3

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Because the solder joint is directly exposed to the air, it is very easy to blacken and oxidize

4

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Now there is a thin layer of flux on the surface of the solder joint, but the solder joint is not easy to oxidize

5

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So we clean the dirt on the solder joints when we are ready to solder

6

00:00:30,300 --> 00:00:32,200

Now the chip has been reballed

7

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We're ready to solder back

8

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Start cleaning now

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00:00:35,733 --> 00:00:37,766

Put a dust-free cloth on it

10

00:00:38,433 --> 00:00:40,533

Wash with a dust-free cloth

11

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The surrounding area of the solder joint must be cleaned

12

00:00:48,900 --> 00:00:53,933

Prevent some dirty things from remaining that cause individual pins to not to stick

13

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After cleaning we are ready to solder

14

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Blows the motherboard a little with the hot air gun

15

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Make the surface heated

16

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Then add a bit of flux in the middle

17

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Spread a thin layer

18

00:01:10,033 --> 00:01:11,166

The thinner the better

19

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As long as there is flux on each solder joint

20

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The thinner the better

21

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Don't add too much

22

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Because after the chip is soldered to the motherboard

23

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When we clean, we can only wash the surrounding flux

24

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The bottom of the chip is not washable

25

00:01:27,033 --> 00:01:28,400

So don't put too much

26

00:01:29,333 --> 00:01:31,266

After the solder paste is applied

27

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We start putting the chips back

28

00:01:33,433 --> 00:01:37,733

When placing the chip, we should pay attention to the position of pin 1

29

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This position is aligned with the direction of the mark

30

00:01:42,600 --> 00:01:44,200

Determine the direction first

31

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Then determine the location

32

00:01:46,033 --> 00:01:47,533

For example, put up

33

00:01:47,600 --> 00:01:51,066

Capacitors are completely stuck, definitely not okay

34

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The capacitor on the right stuck,definitely not okay either

35

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Leave a little gap

36

00:01:56,566 --> 00:01:58,666

Then push the right side a little bit

37

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Leave a little gap

38

00:02:00,466 --> 00:02:01,466

Now it's okay

39

00:02:01,933 --> 00:02:03,933

It doesn't need to be very precise

40

00:02:04,300 --> 00:02:07,100

Just about it, don't slant too much

41

00:02:07,400 --> 00:02:09,366

Still using a straight-air gun

42

00:02:09,766 --> 00:02:15,300

The temperature is still 450 degrees and the air volume is adjusted to the minimum

43

00:02:16,066 --> 00:02:17,300

Then we start welding

44

00:02:18,200 --> 00:02:22,666

After the temperature reaches 450, the air gun points to the chip

45

00:02:22,966 --> 00:02:28,566

Note that the chip will have a slight homing motion during the melting process. Look carefully

46

00:02:32,533 --> 00:02:33,666

Moved a little bit

47

00:02:34,333 --> 00:02:35,700

Now it's welded

48

00:02:40,333 --> 00:02:41,633

Let's weld another one

49

00:02:46,266 --> 00:02:48,966

I didn't make a special mark on this chip just now

50

00:02:49,533 --> 00:02:52,133

The reason is because after the chip is removed

51

00:02:52,233 --> 00:02:57,800

I found that the surface of the chip has a little bit of pinch marks from when we disassembled it

52

00:02:59,566 --> 00:03:00,433

Like this mark

53

00:03:02,366 --> 00:03:04,133

There's a little dirty stuff on it

54

00:03:04,200 --> 00:03:05,200

Let's clean it again

55

00:03:12,133 --> 00:03:13,066

This position

56

00:03:15,000 --> 00:03:19,833

This is how the tweezers went from this direction when it was just disassembled

57

00:03:20,033 --> 00:03:21,700

A little bit of this pinch mark

58

00:03:21,866 --> 00:03:26,766

At this time, we will align this position to the right side of the current direction

59

00:03:27,833 --> 00:03:30,800

We just took the chip from here and took it off

60

00:03:31,466 --> 00:03:35,533

If you can see clearly marked places, you don't need to mark them

61

00:03:37,266 --> 00:03:40,500

The position of this chip is slightly tilted by me

62

00:03:40,900 --> 00:03:43,766

For example, the left side we see now

63

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The above part is slightly to the right

64

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The lower part is slightly to the left

65

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A slight movement will be noticeable as the solder melts. Look carefully

66

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The air gun is still 450 degrees

67

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Minimum air volume

68

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After the temperature reaches 450, we start blowing chips

69

00:04:03,400 --> 00:04:04,200

Don't rush

70

00:04:05,200 --> 00:04:08,200

Now the temperature is good and let's start blowing

71

00:04:09,733 --> 00:04:12,666

This kind of small chip blows at a fixed point

72

00:04:12,766 --> 00:04:16,100

There's no need to sweep the nozzle back and forth like this

73

00:04:16,400 --> 00:04:19,066

Now it's obvious that the chip is moving

74

00:04:19,766 --> 00:04:21,800

OK, the chip is soldered

75

00:04:21,966 --> 00:04:24,866

Now let's look at this position on the left

76

00:04:25,166 --> 00:04:29,800

Are the upper and lower sides of the gap at the same distance from the components now?

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It means it's welded