Sharp 21J-FG1RU, Руководство по обслуживанию

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21J-FG1RU
3 – 14
[2] ADJUSTMENT
ADJUSTMENT PRECAUTION: Makesure TV Set is in “Normal Condition” before switch to Service Mode for Adjustment.
1. PIF ADJUSTMENT
No. Adjustment point Adjustment procedure/conditions Waveform and others
Tuner IFT
( PRESET ) 1 1. Get the tuner ready to receive the CH. E - 9
signal,but with no signal input.
Adjust the PLL data.
2. Connect the sweep generator's output cable to
the tuner antenna. ( RF SWEEP )
3. Adjust the sweep generator's to 80dB
µ
V.
4. Connect the response lead ( use LOW IMPED-
ANCE probe with wave detector ; see Fig.1 ) to
the tuner's IF output terminal. ( This terminal must
have the probe alone connected ).
5. Set the RF AGC to 0 - 6 V with no saturation with
the waveform.
6. Adjust the tuner IF coil to obtain the waveform as
shown in Fig. 2.
Note: Be sure to keep the tuner cover in posi-
tion during this adjustment.
RF-AGC
TAKE OVER
POINT AD-
JUSTMENT
(I
2
C BUS
CONTROL)
(AUTO &
MANUAL ADJ)
1. Receive "PAL COLOUR BAR" signal.
Signal Strength: 56
±
1 dB
µ
V (75 ohm open)
2. Connect the oscilloscope to TP201 (Tuner’s AGC
Terminal) as shown in Fig. 3-1.
3. Call " V01 " mode in service mode. Adjust the " V01 "
bus data to obtain the Tuner output pin drop
0.1~1.0V below maximum voltage.
4. Change the antenna input signal to 63~67dB
µ
V,
and make sure there is no noise.
5. Turn up the input signal to 90~95 dB
µ
V to be sure
that there is no cross modulation beat.
* for Auto ADJ
1) Receive “PAL COLOUR BAR”
signal.
signal strength: 56
±
1dB
µ
V(75
ohm open)
1) Go to service mode.
2) Go to service data V01, press
R/C to operate auto key (Hex
C1) and confirm the ‘OK’
display on the screen.
3) If appear NG, increase data
some step and pls repeat step 2.
4) Proceed step 4 & 5 in manual
mode.
2
»
»
Bias box: About 4.5 V
Oscilloscope
0.1V
TV Set
Bias box
TP201 +
+
—
—
Fig. 3-1
E-9 CH
P C
10k
100k
1n60
75ohm
IF OUT
-1.5+/-0.8dB
1000p
1000p
Oscilloscope
Fig.1
Fig.2