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CIRCUIT DESCRIPTION
DAC2 I004
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 DAC2 IC. The output from the Micropro-
cessor is pin (2 SDA1 and 3 SCL1) which arrives at the DAC2 IC at pins (5 and 6) respectively.
The following is a list of the input and output pins on
DAC
2.
PIN
FUNCTION
1. YUV Det1
Detects activity on Component Input number 1.
2. YUV Det2
Detects activity on Component Input number 2.
3. FH Det Out 1
Test Point 1 (TP1).
4. Sel5
Controls IX02 on 2H PWB. Selects either Y Cb/Cr or Y IQ to com
pensate for Chroma Phase angle used in Auto Color.
5. F Mono
Places the Main Tuner pin (22 mono) into forced Mono Mode.
6. FH Det Out 1
Test Point 2 (TP2).
7. 31/33
Notifies the DCU related to Horizontal Frequency. Either 31.75Khz
for everything but HD or 33.75Khz for HD. The DCU uses two sets
of memory. One for everything but HD and one for HD. This relates
to both Digital Convergence adjustment data and for Magic Focus
memory. Also notifies the Dynamic Focus Horizontal Parabolic
generator to compensate for phase distortion. Also, notifies I701
Horizontal Drive generation IC concerning the Horizontal operation
frequency.
8. Gnd
Ground
9. CS Sel
Not Used.
10. Busy
Informs the Microprocessor that the DCU is in the Digital Conver
gence Adjustment Mode. The Micro. Ignores IR pulses.
11. SAD0
Ground Not Used
12. SAD1
Ground Not Used
13. SAD2
IC B+. (STBY +5V).
14. SDA
Data I 2 C communications between DAC2 and Microprocessor
15. SCL
Clock I 2 C communications between DAC2 and Microprocessor
16. Vcc
IC B+. (STBY +5V).
Level Shift
I014
The Microprocessor operates at 3.3Vdc. Most of the Circuits controlled by the Microprocessor operate at
5Vdc. The Level Shift IC steps up the DC voltage to accommodate.
3D Y/C U204
The 3D Y/C module is a Luminance/Chroma separator, as well as a 3D adder. Separation takes place
digitally inside the module. Using advanced separation technology, this module separates and doesnt
produce dot pattern interference or dot crawl. The 3D effect is a process of adding additional signals to the
Luminance and Chroma. These signals relate specifically to transitions. Transitions are the point where the
signal goes from dark to light or vice versa. The 3D adds a little more black before the transition goes to
white and a little more white just before it gets to white. It also adds a little more white just before it goes