According to the phenomenon, the key to check switch machine control circuit and standby power supply circuit. RW2service manual download site
 RW2service manual download site
Of P27 socket voltage is only 4 feet STB5V 4 v, by IC411 three-terminal voltage regulator output, measured STB5V branch has no obvious short circuit, touch IC411 no fever, show no over-current caused STB5V is low. Failure is due to the low voltage for the CPU and not boot, check the vice power part. Input voltage of 5 v of IC411, normal machine son is 8 v. In optical coupling D416 and zener diode D417, fault, estimated IC410 on load capacity, try to change after troubleshooting.RW2service manual download site