Magnavox MWC20T6, Service Manual

Page: 23 / 80

1-7-3 T1200EA
4. Cut-off Adjustment
Purpose: To adjust the beam current of R, G, B, and
screen voltage.
Symptom of Misadjustment: White color may be
reddish, greenish or bluish.
Notes: Screen Control --- FBT (Sub CBA),
FBT = Fly Back Transformer,
Use the Remote Control Unit.
1. Degauss the CRT and allow the unit to operate for
20 minutes before starting the alignment.
2. Input the Black raster signal from RF input.
3. Enter the Service mode. (See page 1-7-1.)
4. Press the [VOL
p
] button.
(Press [VOL
p
] button then display will change
“C/D”, “7F” and Initial Setting.)
5. Choose CUT OFF/DRIVE mode then press [1]
button. This adjustment mode is CUT OFF (R).
6. Increase the screen control so that the horizontal
line just appears on the CRT.
7. Press the [CH.
o
/
p
] buttons until the horizontal
line becomes white.
8. Choose CUT OFF/DRIVE mode then press [2]
button. This adjustment mode is CUT OFF (G).
Press [CH.
o
/
p
] buttons until the horizontal line
becomes white.
9. Choose CUT OFF/DRIVE mode then press [3]
button. This adjustment mode is CUT OFF (B).
Press [CH.
o
/
p
] buttons until the horizontal line
becomes white.
5. White Balance Adjustment
Purpose: To mix red, green and blue beams correctly
for pure white.
Symptom of Misadjustment: White becomes bluish
or reddish.
Note: Use service remote control unit
1. Operate the unit more than 20 minutes.
2. Face the unit to the east. Degauss the CRT using
a degaussing coil.
3. Input the White Raster (APL 100%).
4. Set the color analyzer to the CHROMA mode and
after zero point calibration, bring the optical
receptor to the center on the tube surface (CRT).
5. Enter the Service mode. Press [VOL
p
] button on
the service remote control unit and select “C/D”
mode. (Display changes “C/D”, “7F” and Initial
Setting cyclically when [VOL
p
] button is pressed.)
6. Press [4] button on the service remote control unit
for Red adjustment. Press [5] button on the service
remote control unit for Blue adjustment.
7. In each color mode, press [CH.
o
/
p
] buttons to
adjust the values of color.
8. Adjust Red and Blue color so that the temperature
becomes 9200K (x: 286 / y: 294) ±3%.
9. At this time, re-check that horizontal line is white. If
not, re-adjust Cut-off Adjustment until the
horizontal line becomes pure white.
10. Turn off and on again to return to normal mode.
Receive APL 100% white signal and confirm that
Chroma temperatures become 9200K (x: 286 / y:
294) ±3%.
Note: Confirm that Cut Off Adj. is correct after this
adjustment, and attempt Cut Off Adj. if needed.
Test Point Adj. Point Mode Input
---
Screen-Control
[CH.
o
/
p
]
buttons
RF
Black
Raster
Tape M. EQ. Spec.
---
Pattern
Generator
See Reference
Notes below.
Figure
Fig. 2
Pattern Generator
RF Input
Test Point Adj. Point Mode Input
Screen
[CH.
o
/
p
]
buttons
RF
White Raster
(APL 100%)
Tape M. EQ. Spec.
---
Pattern
Generator,
Color analyzer
See below
Figure
Fig. 3
Color Analyzer