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CIRCUIT DESCRIPTION
First, it tells the Microprocessor to ignore Inferred Remote commands. It does this by outputting the BUSY
signal from pin (10) of the PDG connector and then through the PSD1 connector pin (1). Then to I004 the
Analog to Digital converter. The Analog to Digital converter outputs this information in digital form through
the I2C bus to the microprocessor. The I2C data is output from pin 14 SDA1 and 15 SCL1 and arrives at
the Microprocessor I001 pins (2 and 3). When the Microprocessor receives this BUSY signal, it ignores all
Inferred Remote commands. Second, tt blanks video so that the DCU graphics can be see easily. This is
accomplished by the same BUSY signal being routed from pin (10) of the PDG connector and then through
the PSD1 connector pin (1). It is then routed through the PSZ1 connector pin (7) to the Rainforest IC IX01
pin (32) as YS2 signal which mutes video.
GRAPHICS PRODUCED BY THE DCU
Cross hatch grid, 3X3, 5X7 or 13X9.
Colored Cursor which blinks indicating the adjustment point
Different text such as, Read from ROM? Write to ROM?
Light pattern for Sensor Initialization
Light pattern for Magic Focus.
The DCU can also turn off individual colors during adjustment. Everything except Green. This is accom-
plished by not producing the particular colors characters from the DCU.
V MUTE 1 EXPLANATION
There are certain times when the Microprocessor or other circuits must Mute the video or audio. The
Microprocessor is responsible for Muting the Audio/Video during Channel Change, Power On/Off, Child
Lock, and AVX Selected with no input, etc . This is accomplished via pin (45) of the Microprocessor.
When V Mute is activated, a high is routed through D028 to the base of Q022 turning it ON. The collector
goes low and pulls the base of Q023 low turning it ON. The emitter of Q023 is connected to STBY +11V,
so when it turns ON, its collector output goes HIGH. This high is now called V Mute 1. V Mute 1 is routed
to two circuits, for Video Mute and for Audio Mute.
FOR VIDEO MUTE
There are three different signals used to mute video on the Rainforest IC, (IX01 pin 25 FBP In). First, V
Mute 1 high is routed through the PSZ2 connector pin (6) to DX08. DX08 sends this high to the base of
QX18 turning it OFF. The emitter of QX18 is connected to the SW +9V line and when it turns OFF the
emitter pulls up HIGH. This pulls up pin (25) of IX01 the rainforest IC and Mutes the Video. Oddly
enough, this high is sent into the same pin as the Flyback Pulse used for horizontal blanking. So it can be
thought of as an extremely long blank pulse. Second, H Blk FC, which is generated by the Flex Converter
U205 at, pin (12 H.BLK). This positive going blanking signal generated in time with Horizontal Sync from
the main picture is routed through the PSZ2 connector pin (12) to DX09 to the base of QX18 turning it
OFF with each positive going pulse. The emitter of QX18 is connected to the SW +9V line and when it
turns OFF the emitter pulls up HIGH. This inputs positive horizontal blanking signals into pin (25) of IX01
the rainforest IC and Mutes the Video. This signals is used for horizontal blanking. Third, V Blk FC, which
is generated by the Flex Converter U205 at, pin (11 V.BLK). This positive going blanking signal generated
in time with Vertical Sync from the main picture is routed through the PSZ2 connector pin (13) to DX10 to
the base of QX18 turning it OFF with each positive going pulse. The emitter of QX18 is connected to the
SW +9V line and when it turns OFF the emitter pulls up HIGH. This inputs positive vertical blanking signals
into pin (25) of IX01 the rainforest IC and Mutes the Video. This signals is used for vertical blanking.
