Tv Start-Up, Tv Normal Run And Stand By Mode Operations; Tv Start-Up Operations; Schematic Diagram For Start-Up Operations; Tv Start-Up And Microcontroller Initialisation - Daewoo DTH-29U3 Service Manual

Color television daewoo dth-29u3

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thermal shutdown circuit (TSD)

This circuit triggers the latch circuit when the frame temperature of STR-F6654 IC exceeds 140 C

overvoltage protection circuit (OVP)

This circuit triggers the latch circuit when the Vin voltage exceeds 22V (typ.)

5.10

TV START-UP, TV NORMAL RUN AND STAND BY MODE OPERATIONS

- When SW801 power switch is pushed, main AC voltage is applied to T801 transformer (after rectification by

D801...D804 diodes). Then, T801 SMPS transformer starts operating and supplies DC voltage to I823(5V regulator),

to I826(3.3V regulator) and to I827(2.5V regulator).

- These regulators provide 3.3V/2.5V DC voltage to I701 microcontroller power supply pins (pins 42/9, pins 11/44) and

to the reset pulse circuit which provides reset pulse to I701 microcontroller reset pin (pin 8).

- Then, the microcontroller starts its initialisation. Its power pin (pin 52) is set to high which allows delivery of power

supply voltages (123V, 8V, 5V...). At this step, all IC's start working but no picture appears on screen: I701 IC doesn't

provide horizontal drive voltage.

CP830F Service Manual

-65-

I826

S/B 3.3V

I827

S/B 2.5V

S/B 5V

I701

MICOM

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