15
Video signal (0.7V PP) supplied from
“CN905 PIN1(RED), 3(GREEN), 5(BLUE)” is supplied
to IC501 PIN4, 6, and amplified through 9C501, C502, C503. PIN 5, C511,
PIN 8 C512, PIN 3 C513 and PIN 10 C514 are a capacitor for filter.
IC501 performs VIDEO PRE AMP and its amplitude is determined by DC BIAS of PIN 11
CHIP. PIN12 (CONTRAST) controls its output video level.
Video signal passing through the DCBIAS and the Contrast control is output to PIN 25 (RED)
PIN 20 (GREEN) and PIN 16 (BLUE), and supplied to Video output circuit.
PIN17, 21, 26 are resistor for Video Drive Control.
PIN 13, 23 and 28 are the Vcc input drives used to provide the power to LM1203IC.
They supply the power of 1.4 V down-converted through R510 and R511 distribution
resistance to PIN 15, 19 and 24 (B, G, R-CLAMP+). PIN 18, 22 and 27 are B, G and R-Drive.
PIN 22 is fixed (G-Drive is fixed as a reference), and PIN 18 and 27 control gains.
Refer to LM1203 Date Book for details.
6-3 VIDEO OUT PUT AMP & BIAS SECTION
Signal supplied from video PRE AMP is sent to Q501 base. The amplitude of Q501 is determined
by EMITTER RESISTOR R518 and COLLECTOR RESISTOR R522. Circuit of C517 is configured
for prevention from and compensation of loss of high frequency.
VIDEO OUT PUT AMP is composed of three circuits of R, G and B. The above description is about
RED circuit. For the description of Green and Blue circuit, see the entire circuit because Location
no. of the parts are differently applied. To provide enough BIAS voltage to the cathode, adjust
V/R503 and R523 to supply 115~125 V to FBT PIN 10, and transmit the amplified video to the
cathode to display.
Understand the characteristics of the parts before you provide after sales service or change the
part value
.
KTN-2001/1401
KORTEK Corporation
