Symptom suspected by the protection circuit. To determine which part of the circuit caused among the very first to measure the resistance of the triac Q801 found no breakdown short circuit. Boot, measurement and control voltage Q801, there are moments of obvious swing, accompanied by a "click" sound (the sound of the relay release), and the voltage drop OV. Judging, Q80l get the control electrode of the trigger voltage is not normal, so Q801 in a conducting state, a rectifier and filter circuit becomes a voltage doubler rectifier, causing the operation of the voltage doubler rectifier circuit protection. Failure should be out in the AC input automatically switch control circuit. In order to check D817, Q854, D815, Q853, D816, resistors R823 and other elements found in Q853 of c, e very open, R823 circuit. Replacing 2scl685 and R823 (33kΩ) after troubleshooting.mr9service manual download site