Beko L5A Service Manual page 11

A keypad connector (S507) is provided which utilizes the integrated low bandwidth ADC in
gm2221 for scanning 5-6 keys (menu,V+,V-,P+,P- keys standard- source key optional) on
the keypad. The keypad allows access to the OSD without using the remote IR controller.
The L5-A board also has In System Programming (ISP) capability for the external flash
ROM using DDC2Bi. This can be done using the D-Sub 15 (PC) connector on the board.
ISP can also be performed using G-probe through the RS232 interface.
One channel of the dual channel FET power switch (U602) is used to control the power
sequencing to the LCD panel. Depending on the type of the panel, the input voltage to this
FET device can be chosen as shown below:
For +3.3V panels
For +5V panels
For +12V panels
An LM2576, a step-down regulator IC (U600), is used to generate the main +5V_STBY
voltage on the board. This IC can deliver up-to 3 Ampers of 5Volts. There is no stand-by
control for this regulator, which means this IC is always on, as soon as power is supplied
to the board.
U603(+3.3V_STBY) and U605 (+1.8V_STBY) linear regulators are used to supply the
voltage necessary for the GM2221 IC and some peripherals. These voltages are also
available in stand-by mode to power the microprocessor inside gm2221, LED, IR receiver
IC and EEPROM. These devices are necessary to wake up the board from stand-by state.
Second channel of the dual channel FET power switch (U602) is used to control cut some
voltages in stand-by mode. These voltages are +5V, +3.3V and +2.5V. These voltages are
used by the video processor (VPC 3230D), audio processor (MSP 34x0G), teletext
processor (SDA5550), tuner and some peripheral IC's and circuitry. In order to limit the
stand-by power consumption, these voltages are not available in stand-by mode. Also the
audio amplifier (TDA1517) is also in its stand-by mode using its dedicated stand-by pin.
The board employs MSP3410G, a multi-system audio processor solution from Micronas.
The system supports 4 audio input ports, one of which is not used on the L5-A board.
Audio output is provided with speaker and headphone jacks (S409, S401) provided on the
board. The sound IF signal from the tuner is connected to the audio processor directly.
J601 is soldered on the main-board
J600 is soldered on the main-board
J603 is soldered on the main-board