Circuit Description; A Board - Sony FWD-40LX2F Service Manual

The main functions of each board in this unit are as
described below.

. A board

This board mounts an HD15 connector and two HDMI
connector interfaces. It processes a video signal together
with the signal from an option board using a scaler and
outputs data to the display panel. This board also outputs
the selected audio signal to the SP board.
. JT board
This is a relay board used for connecting the option
board and A board of slot 2.
. H1 board
This is a user interface board. This board mounts
[POWER], [INPUT]/[ENTER], [MENU], [UP],
[DOWN], [RIGHT], and [LEFT] buttons.
. H2 board
This board mounts two-color LED, which displays the
status of this unit, and a remote control photosensing
block.
. LOGO board
This is an LED board used for shining a SONY logo.
. SP board
This board mounts a speaker output terminal for audio
output.
. G6 board
This is a power board that has output voltages of STBY5
V, 5 V, 12 V, and 13 V.
FWD-40LX2F
FWD-40LX2X
Section 3

Circuit Description

3-1. A Board
The A board mounts HD15 (CN1), HDMI1 (CN12), and
HDMI2 (CN11) as a video input terminal. The signal from
option slot 1 is input from CN14, and the signal from
option slot 2 is input from CN13 through the JT board.
The RGB/YPbPr signals from HD15, and slots 1 and 2 are
directly input to a scaler circuit (U5). HDMI1 and HDMI2
signals are switched using an equalizer (U20), and the
selected TMDS signal is input to the scaler circuit. An
equalizer switches signals and controls the signal output,
by the port control (SEL_H and CE_H) from a scaler
circuit. The CVBS and Y/C signals from an option slot are
input through a p-type filter circuit to a scaler circuit. The
video signal from which an HDMI signal was eliminated is
input to a scaler circuit without passing through a switch
circuit. However, the RGB sync signals from slots 1 and
2, and HD15 are selected using a switching circuit (U3) by
HV_SA and HV_SB signals and input to a scaler circuit.
The input signal from HD15 is used for a video sync
signal. It is switched using a switching circuit (U4) by a
SYNC_MO signal and input to the port of a scaler circuit
that differs from the case of an H sync signal.
In a scaler circuit, resolution is converted according to the
display panel, and various picture qualities as well as wide-
angle setting or zoom setting are set and LVDS-transferred
to the panel through CN2.
There are the analog input from a mini-jack (CN3), slot 1,
or slot 2 and the digital input from HDMI in an audio
input. An analog audio signal is input to an audio proces-
sor circuit (U14). The audio signal from HDMI is output
from a scaler circuit as an I
audio processor circuit is controlled by I
input and set the sound quality and volume. The selected
audio signal is passed through an amplifier circuit (U17)
and output to the SP board through CN10. The mini-jack
input cannot be only selected as the function of the main
unit only during HD15 input, but also it can be selected as
an audio input during conversion of DVI into HDMI. An
audio signal is muted by the software control of an audio
processor and the hardware control of an amplifier.
2 S signal and input to U14. The
2
C to switch the
3-1