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4. Connect an oscilloscope to the TP304 (IC301 Pin 36) blue
output.
CONTRAST
ADJUSTMENT
Procedure:
1. Short between IC301 pin-46 and pin-33, and between
pin-45 and GND. (Short them at the same time.) Picture
will show the white- compressed picture.
2. Input the 5- to 16-step black and white wave (stair-
step) of the pattern generator (75 Sz and 1 Vp-p) to the
A/V IN jack (J301).
3. Connect an oscilloscope (DC range 1 V/ DIV) to the
TP305 (IC301 pin 34) green output.
4. Adjust RV307 (BRIGHT control) so that the black level
obtains - 3.8V (line K).
Negative polarity Positive polarity
5. Adjust RV301 (contrast) so that the white line obtains
the GND potential (line M) (A = 3.8 t O.lVp-p).
6. Disconnect pin 46 from pin 33 of IC301, and pin 45 from
GND.
WHITE
BALANCE
ADJUSTMENT
When performing this adjustment, set the direct
Note:
current drift .adjustment
on each channel of the oscilloscope is stabilized, and
use the oscilloscope in this condition.
Procedure:
1. Short between IC301 pin-46 and pin-33, and between
pin-45 and GND. (Short them at the same time.) Picture
will show the white - compressed picture.
2. Input the 5- to 16-step black and white step wave (stair
-step) of the pattern generator (75 Sz and 1 Vp-p) to
the A/V IN jack (J301).
3. Connect an oscilloscope (CHl) to the TP305 (IC301 pin
34) green output and (CHZ) to the TP504 (IC301 pin
32) red output.
4. Turn RV308 (SUB CONT R) to adjust the red gain so
that the positive polarity red signal step wave coincides
with the positive polarity green signal step wave on the
oscilloscope.
A : 3.8 !I O.lVp-p
so that the direct currents
5. Connect an oscilloscope (CHl) to the TP305 (IC301 pin
34) green output and (CH2) to the TP (IC301 pin 36)
blue output.
6. Turn RV309 (SUB CONT B) to adjust the blue gain so
that the positive polarity red signal step wave coincides
with the positive polarity green signal step wave on the
oscilloscope.
7. Disconnect pin 46 from pin 33 of IC301, and pin 45 from
GND.
The positive polarity signal and the negative polarity
signal may not simultaneously coincide due to the
variation.(Figures a and b)
In this case, adjust these signals to an average value.
(Figure c)
Figure b
VIF
ADJUSTMENT
Note:
These adjustments are not performed usually. Never
touch CT201 of adjusting device. While, only when
CT201 have been replaced, make the following simple
adjustment.
Procedure:
Input the monochromatic gradation .wave from EXT
ANT IN jack (JlOl).
Connect an oscilloscope to Q314 emitter.
Adjust CT201 so that the synchro signal is maximum
(VIF adjustment).
Receive the broadcasts of 2 to 13ch, and check if the
screen is colored after the synchronism is stopped with
each channel.
To make maximum
adjustment)
Figure c
synchro
c h i p
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