This machine without VG (15V) voltage voltage normal, indicating normal voltage PFC and other parts, faults in the VG voltage generation circuit. VG voltage from switch transformer T401 "second"

Krispy Kreme (11) winding induction voltage fluctuation, D404 diodes rectifier filtering, IC402, C425 (KA7815), IC403 (KA7815) voltage got. To check the above circuit, D404 short circuit, removed it but measurements were normal. Test-D404 on its printed circuit board pads, short circuit still exists. Suspected IC402, IC403 internal breakdown of short circuit, so will the IC402, IC403 removed before measuring PCB D404 pads, no short circuit. After changing the IC402, IC403, respectively, power test, VG voltage, troubleshooting.