Sony BVH-2000, Руководство по эксплуатации и обслуживанию

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Picture Quality in DT Mode and Y ADD ON/OFF
Switch
Applicable to BVT-2000 #10001 to #52899
The vertical movement of the chrominance signal in DT
play mode is reduced by this modification.
The Y ADD ON/OFF switch determines the Y signal
addition in the DT or Bidirex mode.
In the normal play mode, the Y ADD ON/OFF switch does
not affect the operation of the TBC.
Since the picture
characteristics of the TBC output are
different between Y ADD ON and OFF in the DT or Bidirex
mode as follows, select the appropriate
position according
to the tape speed and/or the contents of the picture.
When the VTR is in the DT or Bidirex mode, the following
two status appears alternately in the short period if the tape
speed is +/-1.5
times and above or +/-0.5 times and below
or in the long period if the tape speed is near to +/-1 times.
Status A: The field of the VTR playback signal
coincides with that of the TBC reference signal.
In this case, Y ADD function does not work regardless
of the Y ADD switch position.
Status B: The field of the VTR playback signal does
not coincide with that of the TBC reference signal.
In this case, if the Y ADD switch is set to ON, the
VTR playback
signal is processed by the Y ADD
function and the vertical resolution of the TBC output
signal is reduced by half. It results in an indistinct
picture.
Y ADD
ON
When the tape speed is approximately +/-1.5 times
and above or +/-0.5 times and below, the vertical
movement of the lines is smoothed and the TBC
output picture feels natural.
When the tape speed is near to +/-1 times, distinct
and indistinct pictures may appear alternately in
the long period even though the original picture is
distinct.
Y
ADD
OFF
When the tape speed is approximately +/-1. 5 times
and above or +/-0.5 times and below, the picture
on the monitor screen moves vertically by one line
in the short period and it may seem flicker.
When the tape speed is near to +/-1
times, the
picture moves vertically by one line in the long period
but the picture does not become indistinct.
Modification Procedure
The parts necessary for the modification are prepared
as "BVT-KIT 5".
1pc A-6259-201-A Complete PCB, DP-28
1pc A-6259-202-A Complete PCB, DP-29
1pc 8-759-755-80 IC, MB7052-S3NB, PROM
(Note 1) The PWA No. of the SG-28 board is changed
from A-6259-070-A to A-6259-07Q-B by replacing
IC-F5 with MB7052-S3NB.
(Note 2) BVT-KIT5 does not include the jumpers for
modification.
DO-12/DP-28 board:
Replace 00-12 board with DP-28 board.
BD-5/DP-29 board:
Replace BD-5 board with DP-29 board.
SG-28 board:
Replace IC-F5 with MB7052-S3NB.
Mother board:
Add the 9 jumpers as follows.
(Note) The mother board in the BVT-2000 with serial
number 52701 and up has been modified at the factory.
CN5 (DO-12/DP-28)
CN4 (BD-5/DP-29)
B DATA 2
6
C DATA 2°
B DATA 2
5
YWINH
B DATA 2
4
CWINH
B DATA 2
3
YC SEP
PB BLK
After modification, check and adjust the BVT-2000 referring
to section 2-3 of BVT-2000 Manual.
2-18
BVH-2000(U/C)
BVH-2180(U/C)
BVH-2500(U/C)