Sharp 20U250 Service-Handbuch - Seite 7

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Sharp 20U250 Service-Handbuch
SHIPPING SETTING & CHECKING
(1) The following default data has been factory-set for the E
(By press factory setting 3 key)
ITEMS
LAST PROGRAM/CHANNEL
FLASHBACK PROGARM/CH
DIGIT
C-SYSTEM
S-SYSTEM
SKIP
AFC
VOLUME
CONTRAST
COLOUR
BRIGHTNESS
TINT
SHARPNESS
WHITE TEMP
REMINDER TIMER
ON TIMER
OFF TIMER
LAST POWER
LANGUAGE
BLUE BACK MUTE
HOTEL MODE
0 CHANNEL SKIP
LAST TV/AV
BASS/TRE/BAL
SURROUND
SURROUND LEVEL
Note: After pressing MODEL setting. 0 channel will be skipped.
2
PROM.
DATA SETTING
1
1
2
AUTO
B/G
OFF
ON
1
60
(MAX)
0 (CENTER)
0 (CENTER)
0 (CENTER)
0 (CENTER)
STANDARD
In-active, "--:--"
In-active, "--:--"
In-active, "--:--"
POWER-ON
ENGLISH
ON
OFF
ON
TV
CENT
OFF
CENT
7-1
PIF ADJUSTMENT
NO. Adjustment part
Adjusting procedure and conditions
1
Tuner IFT
1. Get the tuner ready to receive the E-9 CH
(PRESET)
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 80dBµV.
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
position during this adjustment.
2
RF-AGC
1. Receive "PAL COLOUR BAR" signal.
» Signal Strength: 57 ±1 dBµV (75 ohm open)
TAKE OVER
POINT
ADJUSTMENT
2. Connect the oscilloscope to TP201 (Tuner's
(I
2
C BUS
AGC Terminal) as shown in Fig. 3.
CONTROL)
Oscilloscope
+
0.1V
–
Bias box
+
–
» Bias box: About 4.5 V
Fig. 3
3. Call "AG" mode in service mode. Adjust the
"AG" bus data to obtain the Tuner output pin
drop 0.1 V below maximum voltage.
4. Change the antenna input signal to
63~67dBµV, and make sure there is no noise.
5. Turn up the input signal to 90~95 dBµV to be
sure that there is no cross modulation beat.
Waveform and others
1n60
1000p
10k
Oscilloscope
100k
75ohm
Fig. 1
E-9 CH
P
C
-1.5+/-0.8dB
Fig. 2
Note:
For the 50 ohm signal strength
gauge, when not using 50/75
impedance adapter, signal
strength is 52 ±1 dBµV(75 ohm
open), instead of 57 ±1 dBµV
(75 ohm open).
TP201
For the 50 ohm signal strength
gauge,
Precaution:
TV Set
The loss of using impedance
adapter.
7-2
IF OUT