Open lid to check revealed that the machine switches power supply switch (TE840) breakdown short circuit, integrated UC3844 6, 7 feet short, SR1, SR3, SR5 SR6 has burnt out. After damaged components replaced, boot back to normal (SR6 and SR5, SR1 with 31 ω resistor with 34 ohms, SR3 12 ω).
UC3844 for the machine switch power of pulse wide modulation integrated block, 7 feet for integrated block powered, 6 feet output for switch tube powered, 6, and 7 feet short-circuit Hou, 300V DC voltage by SR1, and SR6 directly plus to switch tube g very, led switch tube breakdown short-circuit, 300V voltage all plus to SR3 Shang, SR3 immediately burn broken, zhihou 300V voltage plus to SR5 Shang, SR5 also immediately burn broken. This is the reason why the fault string element is damaged.