Dell E1909Wc 19inch LCD monitor SMPS, Scalar and back-light inverter schematic

Used ICs: TL4941, AO4828L, LD7552BPS, STP10NK70ZFP [FET], TSUM5PEHL-LF-2 [LVDS]

Horizontal Frequency; 30 kHz to 83 kHz

The LCD monitor have a main board, power board, and a key board which house the flat panel control logic, brightness control logic and DDC.

The power board will provide AC to DC Inverter voltage to drive the back-light of panel and the main board chips each voltage.

The Blue LED indicates the monitor is on and fully functional. An amber LED
indicates DPMS power save mode.

Software Flow

1 MCU Initializes.
2 Is the EEPROM [Electrically Erasable Programmable Read Only Memory] blank?
3 Program the EEprom by default values.
4 Get the PWM value of brightness from EEPROM.
5 Is the power key pressed?
6 Clear all global flags.
7 Are the AUTO and SELECT keys pressed?
8 Enter factory mode.
9 Save the power key status into EEPROM. Turn on the LED and set it to green color. Scalar initializes.
10 In standby mode?

11) Update the lifetime of back light.

12) Check the analog port, are there any signals coming?
13) Does the scalar send out an interrupt request?
14) Wake up the scalar.
15) Are there any signals coming from analog port?
16) Display "No connection Check Signal Cable" message. And go into standby mode after the message disappears.
17) Program the scalar to be able to show the coming mode.

18) Process the OSD display.
19) Read the keyboard. Is the power key pressed?

Back-light inverter schematic

Scalar schematic

SMPS schematic

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