Sharp CX51TXZ, Руководство по обслуживанию

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7
7-1 7-2
CX51TXZ
RF-AGC
check cut in
adjustment
(PRE SETTED) 1. Receive “PAL COLOUR BAR” signal.
»
Signal Strength: 54 ± 1 dBµV (75 ohm open)
2. Connect the oscilloscope to TP210 (Tuner’s AGC
Terminal) as shown in
Fig. 1.
3. Drop Input Signal strength to 51 ±1 dBµV (75 ohm
open).
4. Under 1. and 3. conditions, the output voltage
should be no change or below +0.1 V. In addition,
change input signal strength to 57 ±2 dBµV, the
output voltage should be no less than -0.1 V.
5. Change the antenna input signal to 63~67 dBµV,
and make sure there is no noise.
6. Turn up the input signal to 90~95 dBµV to be sure
that there is no cross modulation beat.
Note: For the 50 ohm signal
strength gauge, when not
using 50/75 impedance
adapter, signal strength is
52 ±1 dBµV (50 ohm
open), instead of 54 ±1
dBµV (75 ohm open).
precaution: The loss of
using impedance adapter.
»
Bias box: About 4.5 V
Oscilloscope
0.1V
TV Set
Bias box
TP210 +
+
–
–
Fig. 1
PIF ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
1
PURITY ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
Purity
adjustment 1. Receive the GREEN-ONLY signal. Adjust the
contrast control to have a beam current to
700 µA.
2. Degauss the CRT enough with the degausing coil.
Note: Follow the Job Instruction Sheet to ad-
just the magnetic field.
Vertical Bv
: -0.050 mT (-0.50 gauss)
Horizontal Bh: +0.020 mT (0.20 gauss)
(See page 12.)
3. Maintain the purity magnet at the zero magnetic
field and keep the static convergence roughly
adjusted.
4. Observe the points “a” and “b” as shown in Fig.
2-1 through the microscope. Adjust the landings
to “A” rank requirements.
5. Orient the raster rotation to 0 eastward.
6. Tighten up the deflection coil screws.
»
Tightening torque: 108 ± 20 N (11 ± 2 kgf)
7. Make sure the CRT corners landing meet the “A”
rank requirements. If not, stick the magnet sheet
to correct it.
Note: This adjustment must be done after
warming up the unit for 30 minutes or
longer with a beam current over 700 µA.
Note: Set the service mode by TP1001 and
TP1002 (short) then press factory proc-
ess R/C RGB key to change to RGB
mono colour mode.
* For the following colours press R/C RGB key to
change.
1
* Press R/C RGB key for 1 sec-
ond in NORMAL MODE, the
colour will change to RGB mono
colour mode.
The TEXT Key “R. G. Cy” Key
can be directly use to change
to other colours screen.
Green-only
Blue-only Red-only
redish Absolved
a
b
A
B
A
B
A = B
A = B
Rank "A"
(on the right of the CRT)
Rank "A"
(on the left of the CRT)
Fig. 2-1
Fig. 2-2
Fig. 2-3