Servo decoder board + 3.3V power supply circuit shown in Figure 2, shutdown after pulling the CNL plug measured + 3.3V feet of resistance value 2Fl (normal value of about 301); disconnect Lt4 measuring the resistance value is 2n, disconnect the L17 measurement of the foot of the resistance value for 300 ohms, determine the failure after the L17. Under the C35, it is normal to be judged that the fault can be caused by the short circuit protection of NDV8501, which can be used to restore the limit of short circuit. +3.3V supply current up to 900mA. to burn off limits to protect the tube at least 3A~5A of the current. 3.6V, 1350mAh lithium battery (which is full of short circuit current up to 5A or more), the negative electrode, the C35 positive electrode leads to the use of lead as a connecting pole. Since the voltage of the lithium battery is higher than that of the 3.3V and the current is very high, the time of each connection should not exceed 2 seconds, and the C35 positive pole to the ground resistance value should be measured after each connection. After the first connection for 2 seconds, the surface temperature of the NDV8501 is raised and the resistance value is 8. The red light of the output port of the audio optical fiber is 2011. The servo decoder board testing, the sound, the image and other functions are normal, the fault has been ruled out.