Sony GV-D200E, Service Manual

Page: 121 / 166

5-31
3-7. AUDIO SYSTEM ADJUSTMENTS
[Connecting the measuring instruments for the audio]
Connect the audio system measuring instruments in addition to the
video system measuring instruments as shown in Fig. 5-3-18.
[Adjustment Procedure]
1)
Hi8/Standard8 AFM BPF fo adjustment
2) Hi8/Standard8 AFM 1.5MHz deviation adjustment
3) Hi8/Standard8 AFM 1.7MHz deviation adjustment
4) Digital8 playback level check
5) Overall level characteristics check
6) Overall distortion check
7) Overall noise level check
8) Overall separation check
1. Hi8/Standard8 AFM BPF fo Adjustment
(VC-250 board)
Sets the BPF passing frequency of IC760 so that the AFM signal
can separate from the playback RF signal properly. If deviated. the
mono/stereo mode will be differentiated incorrectly, and noises and
distortions will increase during high volume playback.
Mode Playback
Signal Hi8/Standard8 alignment tape:
For BPF adjustment
(WR5-11NS (NTSC))
(WR5-11CS (PAL))
Measurement Point AUDIO OUT jack LEFT or RIGHT
Measuring Instrument Distortion meter
Adjustment Page F
Adjustment Address 7D
Specified Value The Main and Sub channel distortion
rate should be almost the same
(within ± 1%) and minimum.
Adjusting method:
1)
Select page: 0, address: 01, and set data: 01.
2) Set the Hi-Fi SOUND switch (menu display) to “2”.
3) Select page: F, address: 7D, change the data and minimize the
distortion rate.
4) Press the PAUSE button.
5) Set the Hi-Fi SOUND switch (menu display) to “1”.
6) Select page: F, address: 7D, change the data and minimize the
distortion rate.
7) Press the PAUSE button.
8) Repeat steps 2) to 7) and set the data of address: 7D so that the
distortions rates when the Hi-Fi SOUND switch is set to “2”
and set to “1” respectively are almost the same and minimum.
9) Press the PAUSE button.
10) Select page: 0, address: 01, and set data: 00.
11) Set the Hi-Fi SOUND switch to “STEREO”.
Fig. 5-3-18.
VIDEO OUT
(75
Ω
)
Pattern generator
AUDIO/VIDEO
INPUT
Main Unit
Audio generator
Attenuator
600
Ω
600
Ω
: 270
Ω
(1-249-410-11) + 330
Ω
(1-249-411-11)
AUDIO
LEFT
(White)
AUDIO
RIGHT
(RED)
VIDEO
(Yellow)
Recording
L
R
AUDIO OUT
VIDEO OUT
Main unit
Monitor TV
47k
Ω
47k
Ω
47k
Ω
(1-249-437-11)
Audio level meter
or distortion meter
Playback