Keep the power attached and the power switch turned on.
With a voltmeter (multimeter set to voltage), test these points. They should report 5V and 3.3V
respectfully.
On the bad XL boards, these voltages showed around 3.1V instead of 5V and 2.2V instead of 3.3V.
You can also test with an oscilloscope between these two points:
The output should be the one on the left. On the bad XL board we see this on the right
That part is not functioning correctly. We observed it with our oscilloscope and other tools, and it is producing very strange control signals.那部分功能不正常。我们用示波器和其他工具观察它，它产生了非常奇怪的控制信号
Voltage regulation is all over the place. If we put any load on the circuit, it fails to produce correct voltage.电压调节完全失调。如果在电路上施加任何负载，它都无法产生正确的电压。
You can test our PCBs by plugging a 24VDC power supply into it (2.1mm DC barrel connector). The status light should come on. lf no lights illuminate, the boards are defective. There is a more complex testing procedure attached.您可以通过将24VDC电源(2.1mm直流连接器)插入我们的电路板进行测试。状态指示灯应该会亮起。如果没有指示灯亮起，则表示电路板有故障。附件中有一个更复杂的测试程序。
