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Chapter
4
:
The first path sees the supply voltage being
fed via resistor R861 to the standby relay
RL801 and the relay winding to the collector
of transistor Q853. Transistor Q853 which is
controlled by Q854, is responsible for
switching the TV into and out of standby
mode
under
microprocessor IC, IC1101 pin 52.
When Q853 is switched ON current flows
through the winding of the relay and
collector / emitter junction of Q853. This
current flow causes the relay contact to
close feeding the mains supply to connector
W2. The mains A.C. supply is then fed from
connector W2 to the E-Board via E1 from
where the A.C. supply is fed to the bridge
rectifier D801 and the switched mode power
supply IC IC801.
A 12V supply is also fed from the main
power supply via R863 and D871, this
supply being used to reduce the load on the
standby transformer when the TV is in
normal operation.
the
control
of
the
:
The second path the supply takes is via
resistor R862 to the base of transistor Q852.
This supply being regulated by the zener
diode D873 which is used as a base bias.
3.
The second path from the standby transformer
T802, that the supply voltage follows is via the
rectifying diode D867 and smoothing capacitor
C871. Here the supply is applied to the collector
of Q852. From the emitter of Q852 a 5V standby
supply is fed to the Microprocessor IC1101, the
EPROM IC1102, the EAROM IC1103 and AV
Link circuit consisting of transistors Q1104 -
Q1107.
This supply allows these circuits to operate
during standby which is required to process the
switch ON command from the remote control or
local keys, allowing the TV to be switched out of
standby, or to also process AV Link commands.
The 5V standby supply is also fed to connector W4
where the standby supply is then fed to the V-Board
via connector V15 and to the ON Digital decoder
stage.
43
3DQDVRQLF
EURO 4D Supplement
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