Sony TRINITRON PVM-8041Q Service Manual page 28

PVM-8041Q/8044Q
NTSC 4.43MHZ COLOR DEMODULATION
ADJUSTMENT(RV108,RV112,RV103,RV106)
PAL COLOR DEMODULATION ADJUSTMENT
(RV113,RV2/SEP101, RV110,RV105,RV205)
1. NTSC 4.43MHz - COLOR adjustment (RV108.RV112)
(1) Receive NTSC 4.43 color bar signal (75% color bar).
(2) Connect an oscilloscope to 1024 pin-® (B-OUT).
(3) Adjust R V108 (443NT-COL) so that waveform peaks should have
the same level (most flat).
(B-OUT) (Adjust so that the first and the 4th
peaks should have the same level.) |
less than 20mV p-p
T
(R-OUT)
less than 60mV
1. PAL PHASE Adjustment (RV113,RV2/SEP101)
(1) Receive the special PAL color-bar.
(2) Connect an oscilloscope to emitter of Q127 (R-Y OUT).
(3) Adjust RV113 (PAL-PHASE) so that B-Y (0/180°) anti-PAL
portion (in the R-Y demodulated output) becomes "0" (flat) as
following figure.
(R-Y OUT)
(4) When cyan and magenta have level difference, adjust RV112
(443NT-HUE) and RV108 (443NT-COL) alternatively to remove,
by tracking. (B-OUT)
B-Y (0/180°)
anti-PAL signal
A
.mall 1 ]
When cyan and magenta have
level difference, adjust RV112
and RV108 alternatively to remove.
2. NTSC 4.43MHz - COLOR (R-Y) adjustment (RV103, RV106)
(1) Receive the NTSC 4.43 color bar signal (75%, chroma color bar).
(2) Connect an oscilloscope to the Q127 emitter (R-Y OUT), and
adjust RV103(443NT-SHIFT) so that the output of the burst
section (B-Y axis signal output) becomes 0.
(3) Connect an oscilloscope to IC124 pin-© (R-OUT). Adjust RV106
(443NT-CDL (R-Y)) so that the level difference should beminimum.
* The anti-PAL portion has a small
level difference in every other
horizontal period. So, adjust so
that average becomes "0".
(4) Connect an oscilloscope to emitter of Q128 (B-Y OUT).
(5) Adjust RV2 inside SEP101 so that R-Y (90790°) anti-PAL
portion On B-Y demodulated output) becomes "0" (flat) as following
figure.
R-Y (90790°)
(B-Y OUT) anti-PAL signal
J=L
-O-
The anti-PAL portion has a small
level difference in every other
1 4 horizontal period. So, adjust so
_
4
that average becomes "0 .
4
B
C
D
4 / For the adjustments of (3) and (5), it is also possible to set the color)
less than 20mV level to MAX with the chroma adjusting knob of the unit and erase
1 ythe color of the anti-pal signal section.
J
(Adjust for B=D. [less than 20mV] Also level difference
between B and C should be less than 60mV.)
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