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CIRCUIT DESCRIPTION
Flex Converter U205
The projection television is capable of two different horizontal frequencies. 31.75Khz for everything except
HD and 33.75Khz for HD. (High Definition). The Flex Converter is responsible for receiving any video
input and converting it to the related output. This output is controlled by the input sync and by the
customers menu. The set up can be 4X3 or 16X9 sometimes called letterbox. The Flex Converter can take
any NTSC, S-In, Component in NTSC, Progressive or Interlaced, and 480I, 720P, 1080I signal. Control
for the Flex Converter is Clock, Data and Enable lines. Clock, Data and Enable lines for the Flex Converter
are output from the Microprocessor at pins (20 Clock, 21 Data and 46 FCENABLE). FCENABLE Clock
and Data lines must be routed through the Level Shift IC I014 to be brought up to 5V. They arrive at I014
at pins (2 Clock, 3 Data and 4 FCENABLE) and are output at pins (18, 17 and 16) respectively. DAC1
I003 This Digital to Analog converter acts as an extension of the Microprocessor sometimes called an
Expansion IC. The purpose of this IC is to reduce the number of pins, (fan out) of the Main Microprocessor
I001. The Main Microprocessor sends Clock and Data via I2C bus to the DAC1 IC. The output from the
Microprocessor is pin (2 SDA1 and 3 SCL1) which arrives at the DAC1 IC at pins (5 and 6) respectively.
The following is a list of the input and output pins on DAC1.
PIN
FUNCTION
1. IR Det.
The IR pulse from the Remote Control is monitored when Auto Link is set. (See
Auto Link in Index).
2. YN Det.
Active Low. This pin monitors for active sync when Auto Link is set. (See Auto
Link in Index).
3. Blk Main
Normal High, Blanking Low. Blanks Y-Cb/Cr into Flex Converter.
4. MTS
Places the Main Tuner pin (21 mode) into MTS Stereo. If Tuner receiving MTS
signal. See pin 10.
5. F Mono
Places the Main Tuner pin (22 mono) into forced Mono Mode.
6. Ant
Switches the antenna block into Antenna A or Antenna B when selected.
7. Blk Sub
Normal High, Blanking Low. Blanks PinP Sub Y-Cb/Cr on Terminal PWB before
going into Flex Converter.
8. Gnd
Ground
9. SAP Det
The Main Tuner outputs an SAP LED signal when SAP is detected. Active Low.
10. ST Det
The Main Tuner outputs an ST LED signal when Stereo is detected. Active Low.
11. SAD0
Ground Not Used
12. SAD1
Ground Not Used
13. SAD2
Ground Not Used
14. SDA
Data I 2 C communications between DAC1 and Microprocessor
15. SCL
Clock I 2 C communications between DAC1 and Microprocessor
16. Vcc
IC B+. (STBY +5V)