monitor, VCR, or other accessory at the end of
the Video cable. RGB Video from either a TTL
(digital) or analog source is terminated by the
TTL/Analog switch. TTL Video is terminated by a
2.2K Ohms load impedance and an analog signal is
terminated into 75 Ohms. The Audio sources are
terminated with a 47K Ohm resistor.
Other signal inputs to the I/O Panel are:
Crosshair Video, Horizontal and Vertical Sync,
and Fast Blanking. Crosshair Video, generated on
the Convergence Panel, is fed to J713-1 and
switched into the Video circuits with the
Test/Normal switch SW1 (on the Control Panel).
Crosshair Video is coupled through IC4-1, -2,
Video Buffer Q27, to the Comb Filter J501. Sync
correction is automatic for either digital or
analog RGB Video signals connected into the "D"
connector. If the signal pulses have the wrong
polarity or if the pulses are distorted, Q18 and
IC6 reshape the pulses and correct the polarity.
If Sync pulses are good and the polarity is
correct, the circuit passes the signal without
correction, through IC3-8, -9, Q28, and output
jack J709 to the Horizontal Oscillator Module
input jack J302.
Figure 24 - Audio Switching Circuit
Audio Switching Circuits
The Audio switching circuits,
Figure
24, select
one of four stereo input signals and feeds it
through input preamps and Audio switches to a
common output. When the set is first turned On,
the Audio switching circuits automatically select
Tuner Audio and the Monaural mode. A High
(about 12Vdc) is fed to the I/O Panel J715 from
the Tuner interface Panel. The 12Vdc applied to
IC3-5 and -13 turns On the Tuner Audio
switches IC3-3 to -4 and IC3-1 to -2. Decoded
TV Audio from the Stereo Decoder Module is fed to
the Input/Output Panel J712-1 and -3. It is
then buffered by Q19 and Q20 and switched to the
I/O output J718-4 and J718-1 by IC3-3 to -4
and IC3-1 to -2. The remaining circuits are
identical; however, the High used to turn On
other Audio switches comes from the associated
switch on the Tuner Interface Panel, A/V1,
A/V2, or the RGB switches.
Video/Sync Switching Circuits
The. Video switching circuits on the Input/Output
Panel,
Figure
25, include the Tuner Video
Input Jack J707, Output Buffer Q2, Video
Amplifier Q3/Q4, Video Switch IC2-3/-4/-5;
IC4-3/-4/-5, Video Buffer Q27, and Sync
Buffer Q28. The A/V1 Video circuit components
are: Input 1 and Loop Through 4, Video Amplifier
Q7/Q8, and Video Switch IC1-1/-2/-13. A/V2
circuit components are: Input 7 and LoopThrough
10, Video Switch IC2-1/-2/-13. The Hori-
zontal and Vertical RGB Sync circuit components
are: the Clamp Amplifier Q18, Sync Corrector
IC6
r
and Sync Switch IC3-8/-9/-6.
When the set is turned On, a High from the Tuner
Interface Panel is developed and fed to the Input/
Output Panel J715-1, which turns On Video
Amplifiers Q3 and Q4. The same High at IC2-5
turns On IC2. IC4 is turned on by the same High
that is fed to IC4-5 from J715-1 through D9,
and the Test/Normal Switch SW1. Tuner Video
from the IF Module is amplified by Q3 and Q4,
and the 1Vpp Composite Video signal is fed
through 1C2-3, -4, IC4-3.-4, and Q27 to J717
output and on to the Comb Filter.
23
Summary of Contents for 6810
Page 3: ...Figure 1 Signal Flow Block Diagram...
Page 15: ...Figure 14 TS10 Tuning System Block Diagram...
Page 20: ...Figure 20 Decoder Module Signal Flow Diagram...
Page 30: ...Figure 31 Comb Filter Module Figure 32 Comb Filter Circuit...
Page 35: ...Figure 37 CRT Drive Circuit 4...
Page 41: ...Figure 47 Keystone Trapezoid Generator o Figure 48 Side Pincushion Generator...
