Purity Adjustment - Sharp 21F-PA330I Service Manual

ADJUSTMENT PRECAUTION:
Make sure TV Set is in "Normal Condition" before witch to service mode for adjustment.
PIF ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions
1 Tuner IFT 1. Get the tuner ready to receive the CH. - 9
(PRESET) signal, but with no signal input.
Adjust the PLL data.
Connect the sweep genertor's output cable to
2.
the tuner antenna. (RF SWEEP)
3. Adjust the sweep genertor's to 80dBµV.
Connect the response lead (use LOW IMPEDANCE
4.
probe with wave detector. (This terminal must
have the probe alone connected).
Set the RF AGC to 0 - 6 V with no saturation with
5
the waveform.
6. Adjust the tuner IF coil to obtain the wavefrom as
show in Fig. 2.
NOTE: Be sure to keep the tuner cover in posi-
tion during this adjustment.
2 1. Receive "PAL COLOUR BAR" signal.
RF-AGC
+ _
TAKE OVER Signal Strength: 56 1 dBµV (75 ohm open)
2.
POINT Connect the oscilloscope to TP201 (Tuner's
AGCTerminal) as show in Fig. 3.
ADJUSTMENT
(I2C BUS
Oscilloscope
CONTROL)
+
0.1V
(AUTO &
—
MANUAL ADJ)
Bias box
+
—
Bias box: About 4.5 V
Fig. 3
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 63~67dBµV,
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.
Wavefrom and others
10k 1n60 1000p
Oscilloscope IF OUT
100k 1000p 75ohm
Fig. 1
E-9 CH
P C
-1.5+/-0.8dB
Fig. 2
for Auto ADJ
Receive "PAL COLOUR BAR"
signal.
+ _
Signal strength : 56 1 dBµV (75
ohm open)
1. Go to service mode.
TP201 2. Go to service data V01, press
R/C to operate auto key (Hex
C1) and confirm the 'OK'
TV Set
display on the screen.
3. If appear NG, increase data
some step and pis repeat
step2.
4. Preceed step 4&5 in manual
mode.
8-1

PURITY ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions
1 PURITY ADJ. 1. Receive the GREEN-ONLY signal. Adjust the
beam current to ~700 µA.
2. Degauss the CRT enough with the degauss coil.
Note: Follow the Job Instruction Sheet to adjust
the magnetic field.
Vertical Bv: +0.030 mT (0.30 gauss)
Horizontal Bh: +0.20 mT (0.20 gauss)
3. Maintain the purity magnet at the zero magnetic
field and keep the static convergence roughly
adjusted.
4. Observe the points a, b, as show in Fig. 1-1
through the microscope. Adjust the landings to A
rank requirement.
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 µ µ µ µ µ A.
Note: Set to service mode by remote con-
troller then press factory process R/C
RGB key to change to RGB mono col-
our mode.
* For the following colour press R/C RGB(Hex 7E)
key to change.
GREEN BLUE
ONLY ONLY
Signal-colour
screen cleared
Wavefrom and others
a b
30mm 30mm
Fig. 1-1
+ _
A
B
A = B
Fig. 1-2
Rank "A"
(on the right of the CRT)
A
RED B
ONLY
A = B
Fig. 1-3
Rank "A"
(on the left of the CRT)
* Press R/C RGB key for 1 sec-
ond in NORMAL MODE, the
colour will change to RGB
mono colour mode.
8-2