Open the rear lid and check the insurance tube well. Rectifier block and power block were normal (see photo). The 300V voltage at both ends of the C608 is IC601, the voltage of the pin is 300V, the voltage at both ends of the R605 is 5V, the starting state is 0V. The voltage of the secondary C620 is 50V. That power supply is normal, measuring power of other various output voltage were normal, the measured voltage at both ends of the C632 to 15V, C630 at both ends of the voltage to 0V, detection ST8DL05L is reverse resistance values are great pointers only fretting) will change after the new boot voltage at both ends of the C630 is + 5V, when the green indicator lights starting moment is relay voice, Caixian fault excluded.
Note: due to the block S78DL05L three terminal voltage regulator package forms and power plastic tubes similar and in the circuit board welding on the surface of the tube foot character standard for e, B, C, easy to mislead. Another common 7805 pin and S78DL05L pin position opposite, so when the replacement 7805 to reverse 180 degrees install.