SHARP 21BS5
Manual de Servicio

14B-S5 21B-S5

PIF CHECKING PURITY ADJUSTMENT

NO. Adjustment part Adjusting procedure conditions Waveform and others

TUNER IFT Get tuner ready to receive E-9 CH sig1 PURITY 1. Receive GREEN-ONLY signal. Adjust the

(PRESET) nal, but with no signal input. ADJUSTMENT beam current to ~700 (21")/~500 µA (14").

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

a b
10k 1n60 1000p 2. Connect the sweep generator's output cable coil.

tuner antenna. (RF SWEEP) Oscilloscope IF OUT Note: Follow the Job Instruction Sheet to ad-

3. Adjust sweep generator's to 80dBµV. 100k 75ohm just the magnetic field. 4. Connect the response lead (use LOW IMPEDVertical Bv : -0.010 mT Fig. 4-1 must have the probe alone connected). (0.40 gauss)
P C

ANCE probe with wave detector; see Fig.1) to (-0.10 gauss) the tuner's IF output terminal. (This terminal Fig. 1 Horizontal Bh : +0.040 mT

E-9 CH

5. Set the RF AGC to 0 6 V with no saturation (Reference: page 8/21) 6. Adjust tuner IF coil to obtain waveform netic field and keep the static convergence 4. Observe the points a, b as shown in Fig. 4-1

with waveform. 3. Maintain purity magnet at the zero mag-

as shown in Fig. 2. roughly adjusted. -1.5+/-0.8dB A

Note: Be sure to keep tuner cover in posithrough microscope. Adjust the landings Fig. 2 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 CRT corners landing meet the

tion during this adjustment. to A rank requirements. B

A = B

Note: This adjustment must be done after

TAKE OVER » Signal Strength: 57 ±1 dBµV (75 open) For the 50 ohm signal strength warming up the unit for 30 minutes POINT gauge, when not using 50/75 or longer with a beam current over ADJUSTMENT 2. Connect the oscilloscope to TP201 (Tuner�s impedance adapter, signal 700 (21") µA. (I C BUS AGC Terminal) as shown in Fig. 3. strength is 52 dBµV(75 ohm (For 14", the beam current should be ±12 CONTROL) open), instead of 57 dBµV A over 500 ±1 µA). Note: Set the service mode by JA122 & 0.1V The loss of using impedance B � ess R/C key change to RGB adapter. mono colour mode. * For the following colours press R/C RGB key to change.
Oscilloscope

A rank requirements. If not, stick the magnet sheet to correct it. Rank "A" (on right of the CRT)

Fig. 4-2 2 RF-AGC 1. Receive "PAL COLOUR BAR" signal. Note:

8
Fig. 3 (on left of the CRT)

(75 ohm open). + TP201 Precaution: JA124 (short) then press factory proc-

Bias box TV Set A = B

+

� Fig. 4-3

» Bias box: About 4.5 V
Red Green Blue only

Rank "A"

3. Call "AG" mode in service mode. Adjust the

* Press R/C RGB key for 1 second "AG" bus data to obtain the Tuner output pin will change to RGB mono colour mode.

Signal colour

screen cleared

in NORMAL MODE, the colour 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 90~95 dBµV to be

sure that there is no cross modulation beat.

8-1 8-2