JVC HR-D540EE - Page 38

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@ Before the following adjustments:
1. Connect a cable to ANT IN and terminate TV OUT at 75 Q.
2. Set a TV channel signal generator as follows.
Video : 65 dBu/75 Q, color bar 87.5% modulation
Audio : 55 dBu/75 Q, 1 kHz + 50 kHz deviation
2 |RFAGC iF terminal | R21
of Front end |(RF AGC)
MONITOR R21
CN1-4
(VIDEO
OUT}
(Color
level)
(TUNER CTL
board)
Color Level
waitin
|
2
B: magenta
Fig. 2-7-3
2-8
e TV signal
e Tuner mode
e TV broadcast
e Tuner mode
e@ TV broadcast
e Tuner mode
e TV signal
© Tuner mode
© Color bar
A:B=1:0.48
1. Connect the oscilloscope to IF terminal of UHF
Tuner (Front end). Adjust R21 for maximum
level, then again adjust R21 for —5 dB again.
Alternate method:
Note: Adjust R21 (RF AGC) to correct for excess
noise in the picture or when streaky cross
interference occure bue to strong electrical
fields.
1. Adjust R21 to minimize noise or streaks on the
TV screen.
2. Check for absence of abnormality on all chan-
nels.
. Receive a color broadcast or signal generator on
a VHF-HI channel.
2. Connect oscilloscope to pin 16 of IC1.
3. Set the oscilloscope to DC mode and adjust T3
to set the lower adge of the ripple waveform to
45 V.
1. Receive a color bar signal. Set the Y levelfor
100% reference signal and then adjust R40 for
a magenta level of 48% at pin 4 of CN1.