当你的C3突然无法开机（屏幕不亮时），请不要慌张，可能的原因也就这几种：

1、屏幕坏了，系统其实已经正常启动了，但是屏幕坏了，没有显示

2、电源不通，有可能数据线坏了

3、系统软件故障，无法正常启动

4、最糟糕的情况，主板故障，真的没有开机启动

When your C3 suddenly fails to turn on (the screen doesn't light up), please don't panic, the possible reasons are as follows:

1. The screen is broken, and the system has actually started normally, but the screen is broken and there is no display

2. The power supply is not working, it is possible that the data cable is broken

3. System software failure, unable to start normally

4. In the worst case scenario, the motherboard malfunctions and there is really no boot up

那么我们应该如何判断呢？

第一，我们可以通过观察C3背面的led灯，这个led灯其实指示的是内置panda（也就是stm单片机的状态），通过它，我们可以基本判断主板是否通电，led缓慢闪烁，表示主板正常通电，什么也没有，那就是主板没有通电，考虑主板故障或者数据线故障。

第二、如果通电没有问题，那么我们可以将C3连接到windows电脑（使用usbc转usba），使用XCOM这个小工具

So how should we make a judgment?

Firstly, we can observe the LED light on the back of C3, which actually indicates the status of the built-in Panda (i.e. STM microcontroller). Through it, we can basically determine whether the motherboard is powered on. If the LED flashes slowly, it indicates that the motherboard is powered on normally and there is nothing, which means that the motherboard is not powered on. This suggests that there is a motherboard or data cable fault.

Secondly, if there is no problem with powering on, we can connect C3 to a Windows computer (using USBC to USBA) and use the XCOM tool

选择串口，设置波特率115200
Select serial port and set baud rate to 115200

然后点击打开串口，在下面的输入框输入comma，然后点击发送
Then click to open the serial port, enter comma in the input box below, and click send

出现password，再点一次发送
Password appears, click send again

看到这个熟悉的画面，那么恭喜你，系统正常启动，那么大概率就是屏幕坏了

Congratulations on seeing this familiar screen. The system is starting up normally, so there is a high probability that the screen is broken

如果串口没有任何反应，那么很遗憾，问题严重，主板可能故障或者系统故障，可以试试救砖教程。
If there is no response from the serial port, it is regrettable that the problem is serious. The motherboard may have malfunctioned or the system may have malfunctioned. You can try the recovery tutorial：https://mr-one.cn/?post=24