As can be seen from the switching principle, regardless of the circuit switching for any reason an error occurs, the harm is very serious, possibly enabling a large area burned. To avoid this phenomenon, the aircraft was designed three-way protection measures voltage doubler rectifier malfunction.nDiservice manual download site

    1. R816, R817, R818 constitutes a voltage divider circuit. When the voltage regulator R818 is higher than the value of the D820, D820 breakdown conduction, Q803 conduction, switching transformer T801 ① ② winding produces a voltage rectified by the D803, then by Q803, D822 added IC801 (sTR-M6529F04) of ④ feet, making it the internal 0cP from the control circuit, causing osc oscillator circuit stops oscillating, Ic801 internal switch stops working, no power output.nDiservice manual download site
 nDiservice manual download site

    2. After the high pressure caused by abnormal conduction D820, D821 will simultaneously breakdown conduction, the optocoupler D819 phototransistor conduction, the Q852 deadline, RL801 relay coil power loss caused by the release of the contacts, cutting off the main power supply of AC power , the machine enters protected.nDiservice manual download site

    3, the rectifier circuit to produce abnormally high pressure, switching transformer T801 ① ② induced electromotive force a winding will rise, D803 DC voltage rectified by this force, c811 filter produces a corresponding increase, add to Ic801 ⑤ feet (ie oVP overvoltage protection monitoring end) when the voltage exceeds the protection threshold, Ic801 internal OVP circuit from the control immediately, so that osc oscillator circuit stops oscillating, FET switch is turned off, no power output.nDiservice manual download site