3. TUNER ADJUSTMENT 3-1. AGC Adjustment
(3) Using a DC power supply, add DC3.0V ± DC0.2V of voltage to the IC301 Pin10 (TP14). (4) Make adjustments with L203 so that the waveform�s center section (a section in the figure below) of the ALIGNMENT SCOPE becomes 45.75 MHz ± 50 kHz. (1) Receive a NTSC signal of RF INPUT under the following conditions. Input level: 58 dBµ Modulation percentage: 87.5% Received channel : US TV 10ch (fp = 193.25MHz) (2) Adjust SFR201 so the voltage at the TU101 Pin1 (TP15 or JW101) is 6.8V ± 0.2VDC. (Simple Adjustment Method) (1) Using the LEADER LCG-401 (65dBµ), receive the color bar signal on channel 2. (2) With SFR201, make adjustments so that the voltage of TU101 pin1 becomes 3.6VDC. (3) Receive a television broadcast, and verify that the screen is clear.
45.15
46.35
a
47.75MHz
3-2.
VCO Adjustment
(5) Remove the capacitor.
( Rough Adjustment ) (1) Make connections as they appear below.
3-3.
AC POWER SUPPLY TU 101 Pin ! (TP2, IF)
10 TP14
AFT Adjustment
(1) Connect the resistance of 1 k� between the TU101 Pin11 and the GND.
TU 101 11 TP2 1k�
ATT
IC301 44 TP12
LSW � 480 VIF
ALIGNMENT SCOPE
(2)
Connect between Pin52 and GND of IC301 with capacitor.
(2) Input the following signal conditions to the TU101 Pin11. (AM/FM SSG) CARRIER 45.75 MHz LEVEL 100 dBµ MOD OFF (3) Make adjustments with L206 so that the voltage of the IC301 Pin47 (TP16) is DC4.5V ± DC0.2V. (4) Remove resistance (1 k�). ( Simple Adjustment Method )
IC301 52 + CAP, 10/50 + C207 0.47/50
(1) Using the pattern generator LCG-401, receive the signal for channel 2. (2) Adjust L206 so that the voltage at IC301 Pin47 (TP16) becomes 4.5V ± 0.3VDC. (3) Receive each television broadcasts and vertify that the picture is clear.
