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[CRT Circuit]
7. CRT Cut Off, White
Symptom when
Adjustment purpose
To set the cut off point of the three CRTs.
Monochrome with color tint, or incorrect brightness.
incorrectly adjusted
Measuring
instrument
Oscilloscope,
DC Ampere Meter
Test point
TP6R, TP6G, TP6B
EXT trigger
| —
Measurement | DIV 5V
range
TIM 10us
Input signal
input terminal
P|
Name
PCB-CRT(R)
(COMPONENT SIDE)
+)
-
R6RO @ TPER
PCB-CRT(G
(COMPONENT SIDE)
(+)
(-)
R6GO ? TPEG
|
PCB-CRT(B)
(COMPONENT SIDE)
(+)
)
R6BO ? TP6B
[Om tt o |
ae
as
Focus Pack
(SCREEN conirol)
FRONT VIEW
1. Select the EXT-1 input with no signal supplied.
2. Press the "MENU" button on a remote hand unit.
3. Press the buttons "2", "3", "5" and "7" in that order.
(The screen will change to the circuit adjustment mode.)
4. Set the function to "VCH". ("'AUDIO" button)
§. Set the items shown in the Table to the given data values.
6. Observe the waveform at TP6R.
7. Adjust the SCREEN control (R) so that the voltage is 210V.
8. Observe the waveform at TP6G
9. Adjust the SCREEN control (G) so that the voltage is 210V.
10. Observe the waveform at TP6B.
11. Adjust the SCREEN control (B) so that the voltage is 210V.
1,
4
12. Supply a VIDEO signal (white raster).
13. Set the data of "7 DRG" and "8 DRB" so that the white level is optimum at the
center of the screen.
14. Observe the waveform at TP6G.
15. Set the data of "6 CTG" so that the voltage is 210V.
16. Observe the waveform at TP6B.
17. Set the data of "6 CTB" so that the voltage is 210V.
18. Measure the DC current as indicated in Table 1.
Note: The internal resistance of the ampere meter must be 30Q or less, and the
length of a lead wire should be 30cm or less.
Connect a resistor, with a value equal to the internal resistance of the
ampere meter, to each of the two CRTs not being measured. This is so that
the load on each CRT will be equal.
Make sure that the current in GREEN and BLUE CRTs does not exceed the
values shown in Table 2.
If excessive, repeat steps 1 through 18 readjusting the current settings to
under the values given in Table 2.
19. Write the data into memory. (Press "ENTER")
20. Terminate the circuit adjustment mode. (Press "MENU" twice)
Note: Adjustment 10 (Sub Cont) must be performed immediately after this
adjustment.
(_Pesitive
| Negative __|
Table 1
:
580pA
530pA
Table 2
—-24—
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