Board Adjustment; Return Video Demodulation Adjustment - Sony CA-550 Maintenance Manual

3-5. DM-98 Board Adjustment
3-5. DM-98 Board Adjustment
This adjustment requires a completely-aligned MSU-700.
Refer to Section 3-1-3 and 3-1-4 for connection and initial
settings.
3-5-1. RETURN VIDEO Demodulation
Adjustment
Notes:
• This adjustment is necessary only when replacing the
DM-98 board, or replacing LV1 or LV2 on the board.
• Use a plastic core driver to adjust 1LV.
• Use a TRIAX cable whose length is 300 to1000 m for
this adjustment.
Equipment : Waveform Monitor Vectorscope
Video Signal Generator
(provides a 10-step signal with
CHROMA signal)
Preparations :
• Set S1-1 to S1-4 /DM-98 (D-2) to all OFF.
• Feed the10-step signal from the video signal generator to
the RET 1 IN connector on the CCU rear panel.
Test Point : RET OUT connector/
CA-550/550P
Adjustment Points : 1LV1 (RET FREQ)/DM-98 (B-1)
1LV2 (RET TUNE)/DM-98 (C-6)
F E
S1
DM-98 BOARD (COMPONENT SIDE)
3-16 (E)
D C B A
1
LV1
2
3
4
5
LV2
6
Adjustment Procedures
1. Temporarily adjust 1LV2 (C-6) so that the waveform
appears observing the waveform monitor.
2. Adjust 1LV1 (B-1) so that the values of DG and DP
are minimum observing the vectorscope.
3. Slightly turn 1LV2 so that they are further minimum.
4. Adjust 1LV1 and 1LV2 alternately until the specifi-
cations are satisfied.
: DG = ±3%, DP = ±3°
Specifications
R
Y
L
G
(For NTSC)
R
Y
L
G
(For PAL)
Note :
• After the adjustment is complete, set S1-4/DM-98 to
ON.
:
M
G
B
C
Y
M
G
B
C
Y
CA-550
CA-550P