SHARP 21D2X
Manual de Servicio

21D2-X

ADJUSTMENT PRECAUTIONS: Make sure TV set is in "Normal Condition" before switch to Service Mode for adjustment.

PIF PURITY ADJUSTMENT
beam current to about 700 µA. ( PRESET ) signal,but with no signal input.

No. point Adjusting procedure/conditions Waveform or others

Tuner IFT Get tuner ready to receive CH. E 9 1 PURITY ADJ. 1. Receive GREEN-ONLY signal. Adjust the

Adjust PLL data. 2. Degauss CRT enough with the degausing coil.

2. Connect sweep generator�s output cable 10k 1n60 1000p Note: Follow the Job Instruction Sheet to
Oscilloscope IF OUT

a b
100k 75ohm

tuner antenna. ( RF SWEEP ) adjust the magnetic field.

3. Adjust the sweep generator�s to 80dBuV. Vertoca Bv: +0.030mT (0.30 gauss) 4. Connect the response lead ( use LOW IMPEDHorizontal Bh: +0.020mT (0.20 gauss)

ANCE probe with wave detector ; see Fig.1 ) to (Reference: page6-2) tuner�s IF output terminal. ( This terminal Fig.1 3. Maintain purity magnet at the zero magnetic must have probe alone connected ). field and keep the static convergence roughly E-9 CH

Fig. 4-1

5. Set the RF AGC to 0 6 V no saturation with adjusted.
P C

waveform. 4. Observe the points a, b as shown in Fig. 4-1

6. tuner IF coil obtain waveform as through microscope. Adjust landing to the

shown in Fig. 2. -1.5+/-0.8dB rank requirements. A

5. Orient the raster rotation to 0 eastward.
Fig.2 Note:Be sure to keep tuner cover in position 6. Tighten up the deflection coil screws.

during this adjustment. » Tightening torque: 108 20 N (11 ± 2 kgf) B

7. Make sure CRT corners landing meet the rank requirements. If not, stick the magnet sheet A = B
2 RF-AGC 1. Receive "PAL COLOUR BAR" signal. Note: For the 50 ohm signal

to correct it.

TAKE OVER » Signal Strength: 57 ± 1 dBµV (75 ohm open) strength gauge, when not Note: This adjustment must be done after POINT AD2. Connect the oscilloscope to TP201 (Tuner AGC u s g 0 / 7 5 i m p d a n c e warming up the unit for 30 minutes or Fig. 4-2 JUSTMENT Terminal) as shown in Fig. 3. adapter, signal strength is longer with a beam current over 700 µA. (I C BUS 52±1dBµV(75 ohm open), in(on right of the CRT)2 CONTROL) Oscilloscope stead of 57±1dBµV (75 ohm
Rank "A"

0.1V 138(short) then press factory process Precaution: The loss of using

+ TP201

Note: Set the service mode by JA137 & JA open). colour mode. A * For the following colours press R/C RGB key to
�

8
8-1 8-2

� R/C key change to RGB mono impedance adapter

Bias box TV Set

+

B change. A = B

» Bias box: About 4.5 V Fig. 4-3

Fig. 3

3. Call "AGC" mode in service mode. Adjust the Blue-only Red-only Green-only

4. Change the antenna input signal to 63~67dBµV, (on left of the CRT)

"AGC" bus data to obtain the Tuner output pin drop 0.1V below maximum voltage. Rank "A" and make sure there is no noise. Signal-colour screen cleared

5. Turn up the input signal 90~95 dBµV to be sure * Press R/C RGB key for 1 sec-

that there is no cross modulation beat. ond in NORMAL MODE, the

colour will change to RGB mono colour mode.