Circuit Descriptions, List Of Abbreviations, And Ic Data Sheets - Philips 29PT5445/85 Service Manual

EN 44 9. L03.1U AA

9. Circuit Descriptions, List of Abbreviations, and IC Data Sheets

Index of this chapter:
9.1 Introduction
9.2 Source Selection
9.3 Audio
9.4 Video
9.5 Synchronization
9.6 Deflection
9.7 Power Supply
9.8 Control
9.9 Abbreviation List
9.10 IC Data Sheets
Notes:
• Only new circuits (compared to the L01.2 chassis) are
described in this chapter. For the other circuit descriptions,
see the manual of the L01.2L AA. This manual is available
in different languages:
– 3122 785 11800 = Spanish.
– 3122 785 11820 = Portuguese.
• Figures can deviate slightly from the actual situation, due
to different set executions.
• For a good understanding of the following circuit
descriptions, please use the block diagram in chapter 6,
and/or the electrical diagrams in chapter 7. Where
necessary, you will find a separate drawing for clarification.
9.1 Introduction
The "L03"' chassis is a global TV chassis for the model year
2003 and is used for TV sets with screen sizes from 14 inch to
21 inch, in Super Flat and Real Flat executions. In comparison
to its predecessor (the "L01"), this chassis is further simplified:
it contains economized executions of the power supply, the
video processing (microprocessor), and the audio processing.
The standard architecture consists of a Main panel (called
"family board"), a Picture Tube panel, a Side I/O panel, and a
Top Control panel. The Main panel consists primarily of
conventional components with some surface mounted devices
in the audio and video processing part.
Tuner + IF
Video Processing
Rear I/O
Audio Processing
Deflection
Figure 9-1 Top view family board
The functions for video processing, microprocessor (P), and
CC/Teletext (TXT) decoder are combined in one IC (TDA937x),
the so-called Ultimate One Chip (UOC). This chip is mounted
on the component side of the main panel.
Circuit Descriptions, List of Abbreviations, and IC Data Sheets
CRT Panel
Audio Amplifier
Front Control
Power Supply
CL 36532044_035.eps
Front Control
Power Supply
Figure 9-2 Bottom view family board
The L03 can be divided into two basic systems, i.e. mono and
stereo sound. While the audio processing for the mono sound
is done in the audio block of the UOC, external audio
processing ICs are used for stereo sets.
The tuning system features 181 channels with on-screen
display. The main tuning system uses a tuner, a
microcomputer, and a memory IC mounted on the main panel.
The microcomputer communicates with the memory IC, the
customer keyboard, remote receiver, tuner, signal processor IC
and the audio output IC via the I2C bus. The memory IC retains
the settings for favorite stations, customer-preferred settings,
and service / factory data.
The on-screen graphics and closed caption decoding are done
within the microprocessor where they are added to the main
signal.
The chassis uses a Switching Mode Power Supply (SMPS) for
the main voltage source. The chassis has a 'hot' ground
reference on the primary side and a cold ground reference on
the secondary side of the power supply and the rest of the
chassis.
9.2 Source Selection
The Source Select is divided mainly into two types, the "Mono
Source Select" and the "Stereo Source Select".
• The Mono Source Select, both audio and video, will be
done entirely by the UOC and will only be able to select one
external audio source.
• As for the Stereo Source Select, the Panasonic IC, which
is for BTSC decoding also, has 2 audio source inputs used
for source selection, whereas the UOC will take care of the
video selection.
9.2.1 Switching Function for Stereo I/O
130603
Video Source Selection
The video source selection is done by the UOC. The video
setting for LATAM / NAFTA is rather straightforward: a so-
called "WYSIWYG" (what you see on the screen, is what you
get from the video ouput).
Audio Source Selection
The AN5829 (BTSC decoder) device does the external stereo
audio source selection. A maximum of three audio input
sources can be selected. AV1 or FRONT is selected by the
mechanical switch in the front cinch connector.
Tuner + IF
Video Processing
Audio Amplifier
Audio Processing
Deflection
Rear I/O
CL 365320044_034.eps
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