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 short-circuit breakdown phenomenon, indicating that there is no AC voltage automatic switching circuit malfunction. Test for Power thick blocks (STR-M68338F04), is invalid. The key element to check the load of the brightest are no exception. To determine whether the fault is not completely pressure caused by the double rectifier circuit protection, detection D820, D821, Q803 optocoupler D819 and other components were normal. Detection road divider resistors R816, R817 normal, measured resistance is significantly greater than the nominal value of R818 2.2kΩ, remove it found to have broken. After replacing a 2.2kΩ/0.5w resistance, troubleshooting.rbPservice manual download site
 rbPservice manual download site

     Because R818 circuit, making a substantial negative terminal voltage rises D820, D820, D821 breakdown conduction, conduction optocoupler D819, Q852 cutoff relay RL801 contacts release, the state machine remains in standby protectionrbPservice manual download site