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CIRCUIT DESCRIPTION
Receiving Inferred Remote Control Commands:
Whenever the Customer utilizes the Infer-red Remote, the IR receiver will detect these 38Khz inferred pulse
train and amplify them. These pulses are delivered to the Microprocessor at Pin (1). The Microprocessor
decodes this data train and sets off the internal routine related to the command.
There is a time when the Microprocessor ignores the remote commands and that is when the Digital Con-
vergence Unit, (DCU here after) is in operation. The Microprocessor receives a BUSY notification that the
DCU is in operation and simply doesnt respond to remote commands. (See the Digital Convergence
Interconnect Diagram and explanation for complete details.) The BUSY signal is generated from the DCU
at pin (10). Then out pin (1) of the PSD1 connector to pin (10) of I004 DAC2. I004 sends the information
via SCL1 and SDA1 lines from Pin (14 and 15) to the Microprocessor pins (2 and 3).
Receiving Key Input Commands:
The front panel function keys are detected by the Microprocessor via R2 ladder style circuit. In other
words, inside the microprocessor is a group of comparators. The function keys are strung together and each
one has a different resistor value to ground. When the key is pressed, the comparators detect the change is
resistance to ground at pin (20) Clock and convert the related DC value into data the Microprocessor can
understand.
The following shows the resistor value to ground from pin (20) of the Microprocessor, though pin (7) of the
PFS connector to the individual keys.
Channel Up = ground
Channel Down = 1K
Volume Up = 1K + 1.5K or 2.5K
Volume Down = 1K + 1.5K + 2.7K or 5.2K
AVX = 1K + 1.5K + 2.7K + 4.7K or 9.9K
Menu = 1K + 1.5K + 2.7K + 4.7K + 10+ or 19.9K
Controlling the On and Off state of the High Voltage Power Supply.
The Power On/Off function switch has STBY+3.3V applied for the Sub Power Supply, via pin (8) of the
PFS connector through a 1K resistor. The output of the Power On/Off switch is sent through pin (6) of the
PFS to Q014. Q014 is turned on at this time and connected to its Emitter is the Data from the Micropro-
cessor pin (21). The Data is routed from Q014s Collector to Key in pin (10) of the Microprocessor. When
the Microprocessor receives this data at pin (10), it knows to turn on or off the television. This function is
performed by and output from pin (53), which controls Q002. This output from this pin is High when the set
is On and Low when the set is Off.
(For more details related to Power On/Off, see the Power On & Off Circuit Diagram Explanation and
Diagram).
Interaction between the Customers Menu and Chassis controls.
When the Customer accesses the Main Menu, selections can be made by scrolling up and down or left to
right. Each item selected will activate a set of instructions within the Microprocessor and determine the
output state of the related pins.
Outputting On Screen Display information
When its necessary, the Microprocessor generates 1uSec pulses from pins (37 Red, 38 Green and 39
Blue) that are sent to the Rainforest IC (IX01) pins (37 Blue, 38 Green and 39 Red) as OSD signals. When
the OSD signals are high, they turn on the output of the Red or Green or Blue amps inside the Rainforest IC
and output a pulse to the CRTs to generate that particular character in the particular color.