Ntsc 3.58 Mhz Color Demodulation (B-Y) Adjustment; Ntsc 3.58 Mhz Color Demodulation (R-Y) Adjustment (Rv104, Rv107); Ntsc 4.43 Mhz Color Demodulation Adjustment (Rv108, Rv112) - Sony TRINITRON PVM-8042Q Service Manual

5-2-7. NTSC 3.58 MHz Color Demodulation (B-Y)
Adjustment (RV114, RV111)
Input signal: 3.58 MHz NTSC 75 % Color bars signal
(Set Y and B-Y of test signal generator to off.)
Switches: SYNC INT/EXT
LINE/RGB
1. Connect an oscilloscope to emitter of Q128.
2. Adjust RV114 (3.58 NTSC HUE) so that the level other
than the burst portion is flat (Voltage difference = 10 mV
or less).
3. Set Y and B-Y of test signal generator to on.
4. Connect an oscilloscope to pin 30 of IC124.
5. Adjust RV111 (3.58 NTSC COL) so that the level
difference of B signal is minimum (20 mVp-p or less).
Adjust so that the 1st and the 4th peaks should have the
same level.
IC124
PIN-30
5-2-8. NTSC 3.58 MHz Color Demodulation (R-Y)
Adjustment (RV104, RV107)
Input signal: 3.58 MHz NTSC 75 % Color bars signal
(Set Y and R-Y of test signal generator to off.)
Switches: SYNC INT/EXT
LINE/RGB
1. Connect an oscilloscope to emitter of Q127.
2. Adjust RV104 (3.58 NTSC SHIFT) so that the R level
is flat (Voltage difference = ± 15 mV or less).
3. Set Y and R-Y of test signal generator to on.
4. Connect an oscilloscope to pin 41 of IC124.
5. Adjust RV107 (3.58 NTSC COL) so that the level
difference of R signal is minimum.
Specification:
Level difference of B and D = Minimum (20 mV or less)
Level difference of B and C = Minimum (60 mV or less)
A
IC124
B
PIN-41
6. After adjustment, perform section "5-2-7. NTSC 3.58
MHz Color Demodulation (B-Y) Adjustment" again.
5-6
8 INT
8 LINE
20 mVp-p
or less
8 INT
8 LINE
60 mV or less
20 mV or less
C
D
5-2-9. NTSC 4.43 MHz Color Demodulation
Adjustment (RV108, RV112)
Input signal: 4.43 MHz NTSC 75 % Color bars signal
(Set Y and B-Y of test signal generator to off.)
Switches: SYNC INT/EXT
LINE/RGB
1. Connect an oscilloscope to pin 30 of IC124.
2. Adjust RV108 (4.43 NTSC COL) so that the level is flat
(Voltage difference = 25 mV or less).
IC124
PIN-30
3. If cyan and magenta levels are different, adjust RV112
(4.43 NTSC HUE) and RV108 (4.43 NTSC COL)
alternately.
IC124
PIN-30
Cyan Magenta
4. Connect an oscilloscope to emitter of Q127.
5. Adjust RV103 (4.43 NTSC SHIFT) so that the R level
is flat (Voltage difference = ± 15 mV or less).
6. Connect an oscilloscope to pin 41 of IC124.
7. Adjust RV106 (4.43 NTSC COL) so that the level
difference of R signal is minimum.
Specification:
Level difference of B and D = Minimum (20 mV or less)
Level difference of B and C = Minimum (60 mV or less)
A
B
IC124
PIN-41
8. After adjustment, readjust from steps 1 to 7.
8 INT
8 LINE
25 mV or less
60 mV or less
20 mV or less
C
D
MIC
S Chassis