Image normal, indicating that the switching power supply, IC2001 work properly, you should focus on examination 12V power supply circuit. S3 winding measured rectified by D709, C720 filtered voltage is 13V normal; resistance in normal road test R735; measured Q703 c voltage is 0V, the normal value should be 12V. Remove the Q703 detected no abnormal test Q704 b normal voltage is 12V (the voltage provided by the S5 winding), the Q704 remove the testing, found its c, e pole has been the breakdown. Replacing Q704, troubleshooting.LH6service manual download site