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Video signal (0.7V PP) supplied from "CN901 Pin 2 (BLUE), 4(GREEN), 6(RED)" is supplied
to IC901 Pin 4, 6, 8 through "C902, C903, C905." IC901 performs VIDEO PRE AMP and its
amplitude is “determined by DC BIAS of Pin 1, 2, 3. Pin 9 (Contrast) controls its output
video level.
Video signal passing through the DCBIAS and the Contrast Control is output to Pin 19(RED),
Pin 17 (GREEN), Pin 13(BLUE) and supplied to video output circuit.
For details, see KA2141 Date Book.
6-3 VIDEO OUT PUT AMP SECTION
Signal supplied from video PRE AMP is sent to Q903 base. The amplitude of Q903 is
determined by emitter resistor R938 and collector resistor R937 and R945. Circuit of L903
and C935 are configured for prevention from and compensation of loss of high frequency.
Video output amp is composed of three circuits of R. G and B. The above description is about RED
circuit. For description of GREEN and BLUE circuit, see the entire circuit because LOCATION
Numbers of the parts are differently applied. In A/S or when changing values of the parts, apply them
with full understanding of parts’ characteristics. R938 and R937 are 1% (for temperature
compensation) and R945 is 5% (temperature compensation for TR Q903), and for C935, make sure to
use a capacitor of NPO type.
KT-XX03NA
KORTEK Corporation
