Kortek KTN-2001 Service Manual page 17

KORTEK Corporation
KTN-2001/1401
If the voltage to Q401 Base goes up, Vcc voltage goes down steeply, and FE401 becomes inactive.
That makes Q401 Base voltage goes down, and voltage to FE401 Gate goes up, and hence,
FE401 becomes active. Switching operation is performed as these processes are repeated. If high
voltage feeds back, Q401 turns on, and voltage to FE401 Gate is reduced to stop and protect the
circuit. C405, R404 and D405 are the circuits that protect FE401 from surge as it switches.
These sequential actions make power to be supplied to the secondary side of T401 and to each
part. The voltage provided to the secondary side is transformed to DC through D403, leveled in
C414 and C412, removed noise in L401 and C413, and provided to FBT PIN3 to be boosted.
The voltage rectified in D404 is provided to IC501, IC301, IC801, IC201 and HDT for normal
monitor operation.
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