Hitachi 46W500 Training page 73

DP-3X DIGITAL CONVERGENCE INTERFACE CIRCUIT EXPLANATION
EXPLANATION OF THE DIGITAL CONVERGENCE INTERCONNECT DIAGRAM:
INFRARED RECEIVER:
During normal operations, the IR receiver directs it signal to the Main Microprocessor where it interprets the in-
coming signal and performs a predefined set of operations. However, when the Service Only Switch is pressed,
the Main Microprocessor ignores remote control commands. Now the DCU receives theses commands and inter-
prets them accordingly. The Microprocessor is notified at pin 42 when the DCU begins its operation by the
BUSY line. As long as the BUSY line is active, the Main Microprocessor ignores the IR signal.
ON SCREEN DISPLAY PATH:
MICROPROCESSOR SOURCE FOR OSD:
The On Screen Display signal path is shown with the normal OSD information such as Channel Numbers, Vol-
ume Graphic Bar, Main Menu, Service Menu, etc... sent from the Main Microprocessor pins 34, 33 and 32 to the
Rainforest I501 pins 21, 19 and 18. These are positive going pulses, about 5 V p/p and about 3uS in length de-
pendant upon there actual horizontal time for display.
DCU (Digital Convergence Unit P/N CS00731) SOURCE FOR OSD:
The DCU has to produce graphics as well. When the Service Only switch is pressed, the Main Microprocessor
knows the DCU is Busy as described before. Now the On Screen Display path is from the DCU pins 22, 21 and
20 to the Rainforest I501 pins 24, 25 and 26.
The output for the DCU OSD characters is output through the PDG connector pins (20 Dig Red, 21 Dig Green
and 22 Dig Blue). These are routed through their buffers (QK06 Dig Red, QK07 Dig Green and QK08 Dig
Blue) to the PPD1, PPS1 connector pins (1 Dig Red, 4 Dig Green and 8 Dig Blue). Then through their buffers,
(Q519 Dig Red, Q520 Dig Green and Q521 Dig Blue). Then it arrives at the Rainforest I501 at pins (26 Dig
Red, 25 Dig Green and 24 Dig Blue). When a character pulse arrives at any of these pins, the internal color amp
is saturated and the output is generated to the CRTs. Any combination for these inputs generates either the pri-
mary color Red, Green or Blue or the complementary color Red and Green which creates Yellow, Red and Blue
which creates Magenta or Green and Blue which creates Cyan.
OUTPUT STKs IK05 and IK04:
These are output amplifiers that take the correction waveforms generated by the DCU and amplify them to be
used by the Convergence Yoke assemblies for each color.
RV is Red Vertical Convergence correction. Adjust the location either up or down for Red.
RH is Red Horizontal Convergence correction. Adjust the location either left or right for Red.
GV is Green Vertical Convergence correction. Adjust the location either up or down for Red.
GH is Green Horizontal Convergence correction. Adjust the location either left or right for Red.
BV is Blue Vertical Convergence correction. Adjust the location either up or down for Red.
BH is Blue Horizontal Convergence correction. Adjust the location either left or right for Red.
CONVERGENCE YOKES:
Each CRT has a Deflection Yoke and a Convergence Yoke assembly. The Deflection manipulates the beam in
accordance to the waveforms produced within the Horizontal and Vertical Deflection circuits. The Convergence
Yoke assembly manipulates the Beam in accordance with the correction waveforms produced by the DCU.
MAGIC FOCUS SENSORS AND INTERFACE: (8 Sensor Array).
Each of the eight photo cells, called solar batteries in the service manual, have their own amps which develop the
DC potential produced by the photo cells. Each amp is routed through the PDS1 connector and arrives at the PDS
connector on the DCU where the DCU converts this DC voltage to Digital signals. These digital signals are used
only when the Magic Focus Button is pressed and Magic Focus runs or during Initialization of the sensors.
(Continued on page 4)
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