Sharp CX48K4, Service Manual

9

9-1

9-2

CX48K4

HORIZONTAL AND VERTICAL DEFLECTION LOOP ADJUSTMENT

NO. Adjustment part

Adjusting procedure and conditions

Waveform and others

1

2

3

4

5

6

V-LINEARITY
(I

2

C BUS

CONTROL)

V-CENTER
(I

2

C BUS

CONTROL)

V - AMP
(I

2

C BUS

CONTROL)

S-CORREC-
TION

(I

2

C

BUS CON-
TROL)

H - CENTER

SUB-
SHARPNESS

1. Receive Monoscope Pattern Signal.
2. Call the "V-LIN" mode.
3. Increase or decrease "V-LIN" by Volume key till

the horizontal line in the center of monoscope is
just at the position where the blanking starts.

1. Call the "V-CENT" mode.
2. Increase or decrease "V-CENT" by Volume key

till the picture is centered.

1. Call the "V-AMP" mode.
2. Increase or decrease "V- AMP" by Volume key

to set overscan of 9.5% typical.
Adjustment Spec 9.5%  range +1%   -0%.

FIXED DATA, NO NEED TO ADJUST.

1. Call the "H-CENT" mode.
2. Increase or decrease "H-CENT" by Volume key

to center the picture horizontal.

1. Call the "SUB-SHP" mode.
2. Set "SUB-SHP" to 20 by pressing Volume down

key.

PAL CHROMA ADJUSTMENT

NO. Adjustment part

Adjusting procedure and conditions

Waveform and others

1

SUB COLOUR
(I

2

C BUS

CONTROL)

1. Receive the "PAL Colour Bar" signal.
2. Press R/C to set Picture Normal condition.
3. Connect the oscilloscope to Red cathode

(C881 and R885).

»

 Range

: 20 V/div. (AC) (Use 10:1 probe)

»

 Sweep time : 10 µsec/div.

4. Using the R/C call "SUB COL" in SERVICE

mode. Adjust SUB COLOUR bus data, so that
the 75% White & Red portions of PAL Colour
Bar be at the same level shown as Fig. 8.

5. Clear the SERVICE mode.

7

Focus
adjustment

1. Receive the "Monoscope Pattern" signal.
2. Press R/C to set Picture NORMAL condition.
3. Adjust the focus control to get the best focus.

Cy G

B

W Y 100%W

75%

Mg R

Fig. 8

NTSC CHROMA ADJUSTMENT

NO. Adjustment part

Adjusting procedure and conditions

Waveform and others

1

SUB-TINT
(I

2

C BUS

CONTROL)

1. Receive the "NTSC3.58 Colour Bar" signal

through AV in.

2. Connect the oscilloscope to TP853 (Pin (5) of

P882) BLUE-OUT.

»

 Range

: 100mV/div. (AC)(Use Probe 10:1)

»

 Sweep time : 10 µsec/div.

3. Call the "SUB-TINT" mode in service mode.

Adjust the "SUB-TINT" bus data to obtain the
waveform shown as Fig. 9.

4. Clear the SERVICE mode.

PROTECTOR OPERATION CHECKING

NO. Adjustment part

Adjusting procedure and conditions

Waveform and others

1

BEAM
PROTECTOR

1. Receive "Monoscope Pattern" signal.
2. Set CONTRAST MAX.
3. Set BRIGHT MAX.
4. During the Collector & Emitter of Q883/5/7

short, make sure the protector ON and switch
to standby mode.

* Select one of Q883/5/7 to do

each short test.

2

H, V
PROTECTOR

1. Receive "Monoscope Pattern" signal.
2. Connect output of Bias Box to D607 cathode

(R606 side).

3. Set voltage of Bias Box to 18V and make sure

the protector is not work.

4. Set voltage of Bias Box to 27V, and make sure

the protector is work.

A/V INPUT AND OUTPUT CHECKING

NO. Adjustment part

Adjusting procedure and conditions

Waveform and others

1

VIDEO AND
AUDIO OUT-
PUT CHECK

1. Receive the "PAL Colour Bar" signal (100%

White Color Bar, Sound 400 Hz 100% Mod.)

2. Terminate the Video output with a 75 ohm im-

pedance. Make sure the output is as specified
(1.0 Vp-p ±3 dB).

3. Terminate the Audio output with a 10k ohm im-

pedance. Make sure the output is as specified
(1.76 Vp-p ±3 dB).

2

VIDEO AND
AUDIO INPUT
CHECK

1. Using the TV/AV key on the remote controller,

make sure that the modes change in order of
TV, AV1, AV2 & TV again and the video & audio
output are according to the input terminal for
each mode.

3

Other
protectors

1. Once finish rectified Electrolytic Capacitor short

testing in +B line, check all possible damaged
components on +B line.
(Use random selected set for inspection)

Fig. 9

W

SAME LEVEL

Y Cy G Mg R B