Service manual sc-150 – Daewoo DSC-3220E/3220L User Manual

Page 69

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Service manual SC-150

-68-

I810

C O N T R O L L E D

RECTIFIER

R820

R830

C830

R829

Q808

6 V D C

Q809

Q807

H I G H

L O W

P O W E R

L O W

Fig : I810 controlled rectifier switching circuit

* TV set stand-by mode operations

- On stand-by mode, I501 microcontroller pin 1 (power) is set to low.
- So, Q809 collector is set to high.
- Then, I810 controlled rectifier gate pin is set to high and I810 is conducting.
- So, current flows from pin 16 SMPS transformer to the ground via I804 optocoupler and Q810 and Q811 transistors

(which are conducting).

- In these conditions, I801 delivers pulses on light mode and T801 produces voltages with reduced power.
- As I810 is conducting, current flows also from pin 16 SMPS transformer to I823 (5V / 3.3V regulator) for I501

com, IR receiver and front mask buttons supply voltage (then, remote control or front mask buttons can be activated
to leave stand-by mode).