VT-341
8X
W-5118X
VIDEOICHROMA
ADJUSTMENT (Continued)
3.
White Balance and Back Ground Adjustment
Adjusting Point
El
R857:
Green Drive control
Cl
R863:
Blue Drive control
Cl
R421:
Sub-Contrast control
Vote:
srior
to this adjustment, warm up the unit with the
5eam
current of more than
6004
(VT-3418X) I
7004
(VT-51
18X)
for more than 30 minutes.
I. Receive “MONOSCOPE PATTERN” signal with
pattern generator.
!.
Set the Contrast and Brightness controls at MAX
position.
5.
Connect beam ammeter to
TP601
and
TP602.
(Full scale: 3 mA)
4.
Sub-Tint Adjustment
1
j.
Bell Filter Adjustment
Adjusting Point
0
R1882:
Sub-Tint control
1.
Feed
“NTSC
COLOUR BAR” signal to video in jack
with
colour
bar generator at the
AV
mode.
2.
Connect oscilloscope to
TP853
(B
-
Y).
3.
Set the Tint control at the CENTER
(0)
position.
4.
Set Service switch
51401
at the Video Cut position
to cut off the Y-signal.
Adjusting Point
0
T1802:
Bell Filter
1.
Receive
“SECAM
COLOUR BAR” signal with colour
bar generator.
2.
Connect oscilloscope to TP1801 with the
following settings.
l
Range:
0.05V
/
div. AC
l
Sweep Time:
20psec
/
div.
l
Probe:
l/l 0
(3OpF,
1
OMQ
or more)
1.
Adjust the Sub-Contrast control so that the beam
current becomes
0.8
mA
(VT-3418X)
/
1
.l
mA
(VT-
5118X) (rough adjustment).
2.
Adjust the Green Drive control and Blue Drive
control so that the colour temperature is at
10900K.
l
High beam:
0.8
mA
(VT-341
8X)
1.1
mA(VT-5118X)
3.
Adjust the Contrast control and Brightness
control so that the beam current is
approx.
200,&,
and check that the
colour
temperature is
at
9300°K.
If the temperature is not at
9300”K,
go back to “CRT CUT-OFF ADJUSTMENT” and
repeat the adjustment.
(X = 0.285,
Y = 0.292)
1.
Adjust
Colour
control key to obtain the output of
approx.
3Vp-p.
2.
Adjust Sub-Tint control
(R1882)
so that the output
waveform is as shown in figure below.
3.
Return
51401
to CENTER (normal position).
Same
B-Y
//-
level
y
_.z_‘-
-
/@(
/’
/-
.)
.
-
-
W Y
Cy
GMg
R B
-
1.
Adjust the Bell Filter
(T1802)
so that the red
(R)
output and blue
(B)
output will have the same
amplitude.
CY
G
Mg
R
B
‘c_
Same amplitude
r-
9
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