1

00:00:01,500 --> 00:00:05,433

We also need to drag tin on the solder points on the upper layer,

2

00:00:05,433 --> 00:00:07,700

and we operate under a microscope

3

00:00:07,966 --> 00:00:11,900

The small spacer I mentioned just now is actually in this position

4

00:00:12,900 --> 00:00:19,766

There is an upright metal sheet, which is placed in the middle of the upper and lower layers and acts as a support

5

00:00:21,400 --> 00:00:26,800

It is a piece of copper, it is scattered in different areas, there are many places

6

00:00:34,100 --> 00:00:37,333

When separating, some will stick to the middle frame,

7

00:00:37,800 --> 00:00:40,666

and some will stick to the lower mainboard

8

00:00:41,900 --> 00:00:43,333

Here are two

9

00:00:47,366 --> 00:00:49,733

This location also has one

10

00:00:50,833 --> 00:00:53,766

It's not solder, it's a layer of copper

11

00:01:01,766 --> 00:01:05,566

Let's drag the upper layer of tin under the microscope

12

00:01:09,900 --> 00:01:12,200

Apply more solder paste

13

00:01:13,266 --> 00:01:17,433

For the middle frame, we drag the tin on the separate heating table

14

00:01:18,233 --> 00:01:23,566

There is a certain temperature on the heating table, so it is easier to drag the tin

15

00:01:23,966 --> 00:01:28,533

As for the upper mainboard, since there is no way to buckle it on the heating table,

16

00:01:28,533 --> 00:01:30,866

we can only put it under and drag it

17

00:01:31,533 --> 00:01:36,400

So we need to apply a little low-temperature tin on each solder point to neutralize it,

18

00:01:36,400 --> 00:01:40,466

otherwise the solder points on it will be difficult to be dragged off

19

00:01:41,133 --> 00:01:44,400

Because of all models after iPhone 11 ProMax,

20

00:01:44,400 --> 00:01:49,000

the melting point of tin in the solder points of the middle frame has become higher

21

00:01:50,733 --> 00:01:55,466

The iPhone 11 Promax and all previous models use low-temperature solder,

22

00:01:56,233 --> 00:02:01,166

138-degree low-temperature tin, which is very easy to drag

23

00:02:03,366 --> 00:02:07,366

But starting from the 12 series, they use medium-temperature tin,

24

00:02:07,766 --> 00:02:11,833

and it will be difficult to drag it directly with a soldering iron

25

00:02:19,833 --> 00:02:23,966

We can't directly wipe this low-temperature tin on the mainboard

26

00:02:24,500 --> 00:02:28,333

Because it may be scattered to various places when dragging

27

00:02:28,800 --> 00:02:32,033

We put it on top of the mainboard's fixture

28

00:02:45,266 --> 00:02:49,866

When dragging tin, be sure to pay attention to the tin on the soldering iron,

29

00:02:50,233 --> 00:02:53,133

and do not touch the adjacent components

30

00:02:53,366 --> 00:02:56,466

For example, the small inductor next to it

31

00:02:57,033 --> 00:03:00,233

When there is too much tin on the tip of the soldering iron,

32

00:03:00,300 --> 00:03:03,500

the inductor may be knocked off if you are not careful

33

00:04:00,966 --> 00:04:04,233

Give every solder point a bright and full flattening

34

00:04:04,766 --> 00:04:10,066

It will be easier to absorb when we use the tin-absorbing wire to absorb later

35

00:04:37,766 --> 00:04:40,633

We have already dragged the position below

36

00:04:41,233 --> 00:04:46,433

There are a few spots on the middle strip with tin on it, so drag it a bit too

37

00:04:47,433 --> 00:04:50,400

If there is no tin, we can not drag

38

00:04:51,800 --> 00:04:55,466

Well, each point has been finished with low-temperature tin