SHARP CX51K4
Manual de Servicio

PIF ADJUSTMENT
NO. Adjustment part 1 Tuner IFT (PRESET) Adjusting procedure and conditions 1. Get the tuner ready to receive the E-9 CH 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 80dBuV. 4. Connect the response lead (use LOW IMPEDANCE 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. Fig. 2
Oscilloscope

PURITY ADJUSTMENT
Waveform and others NO. Adjustment part 1
10k 1n60 1000p IF OUT 100k 75ohm

Adjusting procedure and conditions 1. Receive the GREEN-ONLY signal. Adjust the beam current to about 700 µA. 2. Degauss the CRT enough with the degausing coil. Note: Follow the Job Instruction Sheet to adjust the magnetic field. Vertical Bv : -0.050 mT (-0.50 gauss) Horizontal Bh : +0.020 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 shown in Fig. 4-1 through the microscope. Adjust the landing to the rank A 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 JA122 & JA124 (short) then press factory process R/C RGB key to change to RGB mono colour mode. * For the following colours press R/C RGB key to change.

Waveform and others

PURITY ADJ.

a

b

Fig. 1
E-9 CH

Fig. 4-1

P

C
-1.5+/-0.8dB

A

B A=B

2

RF-AGC TAKE OVER POINT ADJUSTMENT (I2C BUS

1. Receive "PAL COLOUR BAR" signal. » Signal Strength: 57 ±1 dBµV (75 ohm open) 2. Connect the oscilloscope to TP201 (Tuner�s AGC Terminal) as shown in Fig. 3.
Oscilloscope 0.1V + � Bias box + � » Bias box: About 4.5 V TV Set TP201

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). Precaution: The loss of using impedance adapter

Fig. 4-2 Rank "A" (on the right of the CRT)

7

CONTROL)

A

B A=B

Green-only

Blue-only

Red-only

Fig. 4-3
Rank "A" (on the left of the CRT)

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.
Signal-colour screen cleared

* Press R/C RGB key for 1 second 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.

CX51K3 CX51K4

7-1

7-2