Practice English Speaking&Listening with: How To Fix Damaged Phone When Replacing The Screen

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An OPPO A7X from a CINO fan 粉丝寄修的OPPO A7X

He claimed that he had replaced the screen 粉丝描述自行更换屏幕

Power on, smoking 开机冒烟

There must be short circuit caused by disconnected screen BTB 肯定是屏幕BTB未扣好导致短路

To avoid short circuit, we choose not to test the phone 避免再次短路, 我们先不进行测试

Just take down and inspect it 直接拆开看看情况

Disconnect battery BTB to cut off power supply 先挑开电池断电

Then disconnect main FPC BTB 再依次挑开主FPC BTB

Screen BTB 屏幕BTB

We can see the screen BTB has been damaged 可以看到屏幕BTB短路烧焦

Take down the motherboard 拆下主板

Remove the cameras 再移除摄像头模组

And the battery 移除电池

Then take down the screen 然后取下屏幕

Pick up a damaged OPPO A7X screen 取一块坏的OPPO A7X屏幕

The display has been damaged, but the flex BTB is good 液晶屏坏了但排线BTB还是好的

We are going to transplant the BTB to the scorched screen 我们将它移植到烧毁的屏幕上

Clamp the FPC withhigh temperature adhesive 用高温胶将FPC固定在维修架上

Apply solder flux 加适量助焊剂

Heat it upat temperature 280℃, wind power 20 热风枪280度 风速20下加热

Please note the temperature setting 注意温度把控

Remove the scorched BTB connector 将烧坏的BTB座子拆除

Apply tin wire on the bonding pad 用烙铁加锡线, 给座子焊盘补上一点锡

Clean off the remaining solder flux 清洁干净残余的助焊剂

In the same way, at the same temperature , wind power 同样的方法, 同样的温度、风速

Take down the BTB connector from the damaged screen 将好的BTB座子取下

Apply solder flux 然后加适量助焊剂

Install the BTB connector on the original screen 将好的BTB座子焊接到原机主的屏上去

The temp. and wind power should be lower when welding the plastic FPC 焊接柔性FPC塑胶器件时一定调低温度和风速

280and wind power 20 would be good 280度风速20 就合适

After welding 焊接OK

Remove the remaining solder flux 清洁多余的助焊剂

So the screen has been refurbished 完好如新的屏幕就翻新成功了

Then move to the BTB connector on motherboard 接下来我们更换主板上的BTB座子

Apply solder flux 加适量助焊剂

Set temperature to 370℃, wind power 40 热风枪370度 风速40

Heat it up for 10 seconds 加热10s左右

Take down the damaged connector 取下损坏的座子

Apply tin wire on the bonding pad 用烙铁加锡线给焊盘加一点锡

Clean off the remaining solder flux 清洗干净残余的助焊剂

Apply solder flux again 再加适量新的助焊剂

Here is a new BTB connector 取一颗新的BTB座子

Align at the pins 对齐脚针后

Set temperature to 360℃, wind power 30 热风枪360度,风速30

Heat up and install the connector on the motherboard 加热,将它与主板焊接上

After motherboard cooling off 待主板冷却

Install the screen and test the phone 连接屏幕测试一下

It must be done after disconnecting power supply 一定记住请在断电的情况下扣合

Then connect to DC power supply 然后再接上电源

Power on 开机试试

The current goes up steadily 电流表缓缓上升

The current is normal 电流正常

However, there is no display 但屏幕并无任何反应

Disconnect power supply 断开电源和屏幕

Take down the motherboard 取出主板

Measure the pins that had damaged before 量测下之前烧毁的几个脚针

The first pin is normal 第一脚正常

So is the second pin 第二脚正常

The third pin is abnormal 第三脚对地短路

Check the 查看点位图

The third pin is for screen power supply 这第三脚应该是屏幕的供电脚

From display power supply IC N390 由显示供电芯片N390输出

The power supply goes through N345, N66, and N67 经过电容N345 N66 N67

Voltage stabilized and filtered by N264 电阻N264稳压滤波后

Then to screen connector 供给屏幕座子

The short circuit here is probably caused by the damaged filter 这一路供电短路大概率是这些滤波电容

Or the scorched power supply IC 或供电IC烧坏了

Uncover the heat-dissipating copper foil and thermal grease 揭开散热铜箔和导热硅脂

Use cutting nippers to cut the cover shield 用剪钳将屏蔽框剪开一个缺口

Reveal the repair areas 露出我们需要维修的区域即可

Measure the stabilivolts here 用万用表量测下这几颗稳压电容

Both ends are short circuit to ground 万用表读数显示两端都对地短路

N345 functions as voltage stabilizing, filtering and circuit protection N345这颗大电容在电路中起稳压滤波保护电路的作用

It has the most possibility to be damaged in short circuit faulty 像这中短路烧毁电路的故障中, 优先烧毁的就是它

So we begin with N345 我们优先拆除它试试

Apply thermal grease on SoC SoC上垫上导热硅脂

Heat up N345 加热电容N345

Take it down 将它拆除

Measure it with a multimeter 用万用表量测

The capacitor here is 0 Ohm after N345 being damaged 这颗电容N345被烧毁后变成了0欧电阻

It causes the short circuit 从而导致电路短路

It is a 10uF capacitor 它本应该是一颗10uF电容

Measure the motherboard after taking it down 拆除后再来量测主板

All values are normal 数值正常

No short circuit 电路不再短路

It means the 10uF capacitor has been faulty 说明就是这个保护电容被烧毁了

And its faulty protects the other circuits 感谢它牺牲了自己保护了电路

Install a new 10uF capacitor 我们换上一颗新的10uF电容

After motherboard cooling off 待主板冷却

Apply thermal grease 贴回导热硅脂

Install the cameras 装上摄像头

The screen, battery 装回屏幕和电池

And the motherboard 装上主板

Connect the screen, main FPC BTB and coaxial cable 优先扣屏幕, 主FPC BTB和同轴线

Then install the battery 最后扣上电池

Power on, test the phone 开机测试

Screen on 屏幕亮起

All the display, backlight, and touch screen are normal 显示正常、背光正常、触屏也正常

Problem solved 故障修复成功

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