Open the back cover to check the insurance tube in good condition. Rectifier block and the power supply block all normal (see chart). 300 v voltage on both ends of the boot C608 measurement, foot IC601 (1) voltage is 300 v, R605 ends in shutdown state for 5 v voltage, on to 0 v. Test the subprime C620 ends voltage 50 v. Show that the power supply is normal, other output voltage measurement are normal, measuring C632 voltage on both ends of 15 v, measuring voltage of 0 v on both ends of the C630, detect ST8DL05L direction, resistance are very whose hands only (micro), after the new boot C630 on both ends of the voltage of + 5 v, at this time the green light is lit, boot instantaneous relay suck up vocalist, colorful display troubleshooting. YBWservice manual download site
 YBWservice manual download site
 YBWservice manual download site
Tip: because the three-terminal voltage regulator block S78DL05L power in the form of encapsulation and laminate tubes are similar, and the circuit board welding pin on the surface of the characters of labeled E, B, C, vulnerable to misleading. Another common 7805 pin, in contrast to the S78DL05L pin location, so 7805 will turn 180 ° installed when substitute.YBWservice manual download site