Sharp 14GT15, 14GT20 Service Manual

SERVICE MANUAL

(14GT15) (14GT20)

14GT15 14GT20

S30Y114GT15//

COLOUR TELEVISION

Chassis No. UA-1

14GT15

MODELS

In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used.

14GT20

FEATURE

Favorite Channel

Full Auto Channel Preset and Auto Channel Skip

100-CH Program Memory

CATV(Hyper Band) Ready <Used Frequency Synthesizer Tuner>

AVL(Sound Keeper) Function

Black Stretch Circuit

On Timer/Sleep T imer/Reminder Timer

Blue Back Noise Mute

Front AV-In (14GT-20 Only)

Rear AV -In/Out T erminals

Colour Comb Filter (NTSC Only)

High Contrast Picture

Hotel Mode

Front Headphone JACK (14GT-20 Only)

English / Thai OSD

CONTENTS

Page Page

» SPECIFICATIONS ...........................................2

» IMPORTANT SERVICE NOTES ..................... 3

» ADJUSTMENT PRECAUTIONS..................... 4

» TROUBLE SHOOTING TABLE..................... 27

» SOLID STATE DEVICE BASE DIAGRAM .... 31

» CHASSIS LAYOUT ........................................32

» WAVEFORMS................................................34

» DESCRIPTION OF SCHEMA TIC DIAGRAM . 35 » SCHEMATIC DIAGRAM

■ INFRARED REMOTE CONTROL UNIT .. 36

■ TUNER .....................................................37

■ 14GT15, 14GT20 HOTEL MODE

APPLICATION ..........................................38

■ HEAD PHONE Unit and

CRT Socket Unit...................................... 39

■ MAIN Unit .................................................40

» BLOCK DIAGRAM.........................................44

» PRINTED WIRING BOARD ASSEMBLIES .. 49 » REPLACEMENT PARTS LIST

■ ELECTRICAL PARTS .............................. 54

■ MISCELLANEOUS PARTS...................... 58

■ SUPPLIED ACCESSORIES .................... 58

■ P ACKING PARTS .................................... 58

■ CABINET PARTS .................................... 59

WARNING

The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug and power receptacle, when servicing this chassis. To prevent electric shock, do not remove cover. No user – serviceable parts inside. Refer servicing to qualified service personnel.

SHARP CORPORATION

14GT15 14GT20

SPECIFICATIONS

Convergence................................................................. Self Convergence System

Focus ............................................................Electrostatic Focus High Bi-Potential

Sweep Deflection ..................................................................................... Magnetic

Intermediate Frequencies

Picture IF Carrier.................................................................................. 38.9MHz

Sound IF Carrier Frequency

5.5MHz...............................................................................................33.4MHz

Colour Sub-Carrier Frequency ........................................................... 34.47MHz

Power Input..................................................................... 100 ~ 240V AC 50/60 Hz

Power Consumption........................................................................................ 65W

Audio Power Output Rating.............................................................. 3.0W(at Max.)

Speaker

Size...................................................................................5 x 9 cm Elliptic (1pc)

Voice Coil Impedance ...........................................................16 ohms at 400 Hz

Aerial Input Impedance

VHF/UHF .......................................................................... 75 ohms Unbalanced

Receiving Channel PAL B/G

VHF-Channels ...................................... E2(48.25MHz) thru E12(224.25MHz)

UHF-Channels .................................. E21(471.25MHz) thru E69(855.25MHz)

Dimensions ...................................................................................Width: 351.0mm

Height: 361.0mm

Depth: 359.0mm

Weight(approx): 9.2 kg

Cabinet material.................................................................................... All Plastics

Specifications are subject to change without prior notice.

IMPORTANT SERVICE NOTES

Maintenance and repair of this receiver should be done by qualified service personnel only.

SERVICE OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE

When servicing the high voltage system, remove static charge from it by Connecting a 10K ohm Resistor in series with an insulated wire(such as a test probe) between picture tube dag and 2nd anode lead. (AC line cord should be disconnected from AC outlet.)

1. Picture tube in this receiver employs integral implosion protection.

2. Replace with tube of the same type number for continued safety.

3. Do not lift picture tube by the neck.

4. Handle the picture tube only when wearing shatterproof goggles and after discharging the high voltage completely.

14GT15 14GT20

X-RAY

This receiver is designed so that any X-Ray radiation is kept to an absolute Minimum. Since certain malfunctions or servicing may produce potentially hazardous radiation with prolonged exposure at close range, the followin precautions should be observed:

1. When repairing the circuit, be sure not to increase the high voltage to more than 25.8kV

(at beam 0 µA) for the set.

2. To keep the set in a normal opeartion , be sure to make it function on 22.8kV ±1.5kV (at

beam 800 µA) in the case of the set. The set has been factory - Adjusted to the abovementioned high voltage.

∴If there is a possibility that the high voltage fluctuates as a result of the repairs,

never forget to check for such high voltage after the work.

3. Do not substitute a picture tube with unauthorizerd types and/or brands which may

cause excess X-ray radiation.

BEFORE RETURNING THE RECEIVER

Before returning the receiver to the user , perform the following safety Checks.

1. Inspect all lead dress to make certain that leads are not pinched or that hardware is not lodged between the chassis and other metal parts in the receiver.

2. Inspect all protective devices such as non-metallic control knobs, insulating fishpapers, cabinet backs, adjustment and compartment covers or shields, isolation resistor- capacity networks, mechanical insulators etc.

14GT15 14GT20

ADJUSTMENT PRECAUTIONS

This model's setting are adjusted in two different ways: through the I2C bus control and in the conventional analog manner. The adjustments via the I2C bus control include preset-only items and variable data.

1. Setting the service mode by the microprocessor.

1. Short JA 122 & JA 124 for 1 second and release to switch to the service mode position, and the microprocessor is in input mode. (Adjustment through the I2C bus control). (Use JWS Key to set as well).

2. Press the CH DOWN / UP key on the remote controller to get ready to select the mode one by one.

3. Press the CH DOWN / UP key on the remote controller to select the modes reversibly one by one.

4. Using the VOLUME UP/ DOWN key on the remote controller, the data can be modified.

5. Short JA 122 & JA 124 for 1 second and release to switch to the normal mode (OFF) position, and the

microprocessor is in out of the service mode.

2. Factory Presetting.

1. Short JA 122 & JA 124 for 1 second and release to switch to the service mode position and turn on the main power switch.Initial values are automatically preset, only when a new EEPROM is used (Judge with the first 4 bytes ).

2. The initial data are preset as listed in page 7, 8, & 9.

3. Make sure the data need modify or not (Initial data).

Note: Once the chassis has been assembly together and ready to be POWER ON for the FIRST TIME,

make sure to short JA122 & JA124 to switch to the service mode position first and then turn on the main power switch (See 2-(1) above).

Precaution: If haven't done this initiation, it may possibly generate excessive Beam current.

3. For reference please check with memory map (UA1 Series type RH-iX3368CE Attachment)

SERVICE MODE

AGC &

GEOMETRIC

MODE

↓

AGC TAKE OVER POINT (AGC)

↓

VERTICAL SLOPE (V-LIN)

↓

VERTICAL AMP (V-AMP)

↓

VERTICAL SHIFT (V-CENT)

↓

HORIZONTAL SHIFT (H-CENT)

↓

S-CORRECTION (S-COR)

WHITE POINT

ADJ.

MODE

↓

W.P. RED STD. W.T. (DRI-RS)

↓

W.P. GREEN STD. W.T.(DRI-GS)

↓

W.P.BLUE STD. W.P. (DRI-BS)

↓

W.P. RED COOL W.P.(DRI-RC)

↓

W.P. GREEN COOL W.P.(DRI-GC)

↓

W.P. BLUE COOL W.P. (DRI-BC)

↓

W.P. RED WARM W.P.(DRI-RW)

↓

W.P. GREEN WARM W.P.(DRI-GW)

↓

W.P. BLUE WARM W.P.(DRI-BW)

SUB ADJ.

MODE

↓

MAX VOLUME (SUB-VOL)

↓

SUB CONTRAST (SUB-CON)

↓

SUB COLOUR (SUB-COL)

↓

SUB BRIGHTNESS (SUB-BRI)

↓

SUB TINT (SUB-TINT)

↓

SUB SHARPNESS (SUB-SHP)

↓

MAX HOTEL VOLUME (HTL-VOL)

↓

HOTEL PROGRAM NO(HTL-PRG)

↓

OSD GRB REFERENCE (RGB)

↓

BLACK LEVEL OFFSET R(CUT-R)

↓

BLACK LEVEL OFFSET G(CUT-G)

↓

CATHODE DRIVE LEVEL(CDL)

FORWARD : CH DOWN KEY REVERSE : CH UP KEY * ( ) means OSD display.

FORWARD : CH DOWN KEY REVERSE : CH UP KEY

AGC &

GEOMETRIC

MODE

WHITE POINT

ADJ.

MODE

SUB ADJ.

MODE

Y-DELAY

ADJ.

MODE

MISC.

OPTION

MODE

OPTION

MODE

OFFSET

ADJ.

MODE

(1) In the Service Mode, Key is used to select the mode in the following order.

14GT15 14GT20

Y-DELAY

ADJ.

MODE

↓

Y-D TIME FOR PAL (TV) (DL-PT)

↓

Y-D TIME FOR SECAM (TV) (DL-ST)

↓

Y-D TIME FOR N358 (TV) (DL-3T)

↓

Y-D TIME FOR N443 (TV) (DL-4T)

↓

Y-D TIME FOR B/W (TV) (DL-TV)

↓

Y-D TIME FOR PAL (AV) (DL-PA)

SHARPNESS OFFSET (SECAM) (SHP-OS)

↓

Y-D TIME FOR SECAM (AV) (DL-SA)

SHARPNESS OFFSET (NTSC358) (SHP-O3)

↓

Y-D TIME FOR N358 (AV) (DL-3A)

SHARPNESS OFFSET (NTSC443) (SHP-O4)

↓

Y-D TIME FOR N443(AV) (DL-4A)

↓

Y-D TIME FOR B/W (AV) (DL-AV)

*(Y-D : Y-DELAY)

MISC.

OPTION

MODE

OFFSET

ADJ.

MODE

↓

COLOUR OFFSET (PAL) (COL-OP)

↓

COLOUR OFFSET (SECAM) (COL-OS)

↓

COLOUR OFFSET (NTSC358) (COL-O3)

↓

COLOUR OFFSET (NTSC443) (COL-O4)

↓

SHARPNESS OFFSET (PAL) (SHP-OP)

↓ ↓ ↓

OPTION

MODE

↓

VERTICAL SCAN DISABLE(VSD)

↓

BLACK STRETCH (BKS)

↓

AUTO VOLUME LEVELING(AVL)

↓

FAST FILTER IF-PLL(FFI)

↓

ENABLE VERTICAL GUARD (EVG)

↓

EHT TRACKING MODE (EHT)

↓

OVERSCAN SWITCH OFF(OSO)

↓

AUTO COLOUR LIMIT(ACL)

↓

FORCED COLOUR LIMIT(FCO)

↓

SOUND SYSTEM M (S-M)

↓

SOUND SYSTEM DK (S-DK)

↓

SOUND SYSTEM I (S-I)

↓

SOUND SYSTEM BG (S-BG)

↓

PLAYBACK SECAM (P-SECAM)

↓

FE (RF) NTSC 3.58 (F-N358)

↓

FE (RF) NTSC 4.43 (F-N443)

↓

FE (RF) SECAM (F-SECAM)

↓

VIDEO MUTE AT IDENT LOSS (VMI)

↓

VIDEO MUTE AT PROGRAM

/SOURCE CHANGE (VMC)

↓

HOTEL MODE (HTL)

↓

REDUCED FM DEMODULATION

GAIN FOR BTSC SIGNAL (BTSC)

↓

NUMBER OF EXT AV SOURCE (AV)

↓

FM WINDOW SEVECTION (FMWS)

↓

SOUND MUTE BIT 0 (SM0)

↓

SOUND MUTE BIT 1 (SM1)

↓

THAI LANGUAGE (THA)

↓

ARABIC LANGUAGE (ARA)

↓

MALAY LANGUAGE (MAL)

↓

CHINESE LANGUAGE (CHI)

↓

FRENCH LANGUAGE (FRE)

↓

RUSSIAN LANGUAGE (RUS)

↓

FORCED V-SYNC SLICING LEVEL(FSL)

↓

SYNC OF OSD (HP2)

↓

TUNER CPT (CPT)

↓

BILINGUAL(BIL)

↓

IF AGC SPEED BIT 0 (AGC0)

↓

IF AGC SPEED BIT 1 (AGC1)

↓

FOA Time Constant-RF (FOA-FE)

↓

FOB Time Constant-RF (FOB-FE)

↓

FOA Time Constant-AV (FOA-AV)

↓

FOB Time Constant-AV (FOB-AV)

USER DATA IN SERVICE MODE

The flow of Mode lists as following,

* Direct Key-in Step1 Mode

RC COMMAND SERVICE-ITEM

FUNCTION AGC

CONTRAST DOWN V-LIN

COLOUR DOWN V-AMP

BRIGHTNESS DOWN V-CENT

TINT DOWN H-CENT

SHARPNESS DOWN EW / /

SYSTEM HB

BLUEBACK S-COR

TIMER SUB-VOL

CONTRAST UP SUB-CON

COLOUR UP SUB-COL

BRIGHTNESS UP SUB-BRI

TINT UP TINT SUB TINT

SHARPNESS UP SUB-SHP

CHANNEL 1 DRI-GS CHANNEL 4 DRI-BS CHANNEL 7 CUT-R

CHANNEL FLASH BACK CUT-G

14GT15 14GT20

AFTER SHORT JA 122 & JA 124 ,AND TURN ON THE MAIN POWER SWITCH,READ DATA FROM EEPROM ADDRESS 00H ~ 03H,AND COMPARE TO THE LIST BELOW, IF DIFFERENT, INITIALIZE THE EEPROM.

Address : Data Address : Data

00H : 55H 02H : 43H 01H : 4FH 03H : A1H

EEPROM ITEMS OSD DATA LENGTH

AGC TAKE OVER POINT AGC 0~63 14 ADJ VERTICAL SLOPE V-LIN 0~63 32 ADJ VERTICAL AMPLITUDE V-AMP 0~63 32 ADJ VERTICAL SHIFT V-CENT 0~63 32 ADJ HORIZONTAL SHIFT H-CENT 0~63 32 ADJ S-CORRECTION S-COR 0~63 0 FIX WHITE POINT RED STD WHITE TEMP DRI-RS 0~63 32 FIX WHITE POINT GREEN STD WHITE TEMP DRI-GS 0~63 32 ADJ WHITE POINT BLUE STD WHITE TEMP DRI-BS 0~63 32 ADJ WHITE POINT RED WARM WHITE TEMP DRI-RW 0~63 32 FIX WHITE POINT GREEN WARM WHITE TEMP DRI-GW 0~63 32 FIX (DRI-GS)-7 DATA WHITE POINT BLUE WARM WHITE TEMP DRI-BW 0~63 32 FIX (DRI-BS)-7 DATA WHITE POINT RED COOL WHITE TEMP DRI-RC 0~63 25 FIX WHITE POINT GREEN COOL WHITE TEMP DRI-GC 0~63 32 FIX (DRI-GS)-7 DATA WHITE POINT BLUE COOL WHITE TEMP DRI-BC 0~63 32 FIX MAX VOLUME SUB-VOL 0~63 63 FIX SUB CONTRAST SUB-CON 0~63 63 FIX SUB COLOUR SUB-COL 0~63 32 ADJ SUB BRIGHTNESS SUB-BRI 0~63 32 ADJ SUB TINT SUB-TINT 0~63 32 ADJ SUB SHARPNESS SUB-SHP 0~63 32 ADJ MAX HOTEL VOLUME HTL-VOL 0~63 32 ADJ HOTEL PROGRAM NUMBER HTL-PRG OSD GRB REFERENCE RGB 0~15 15 FIX BLACK LEVEL OFF-SET R CUT-R 0~15 8 FIX BLACK LEVEL OFF-SET G CUT-G 0~15 8 FIX CATHODE DRIVE LEVEL CDL 0~15 0 FIX Y-DELAY TIME FOR PAL(TV) [YD] DL-PT 0~15 12 FIX Y-DELAY TIME FOR SECAM(TV) [YD] DL-ST 0~15 15 FIX Y-DELAY TIME FOR N358 (TV) [YD] DL-3T 0~15 12 FIX Y-DELAY TIME FOR N443 (TV) [YD] DL-4T 0~15 12 FIX Y-DELAY TIME FOR B/W (TV) [YD] DL-TV 0~15 12 FIX Y-DELAY TIME FOR PAL (AV) [YD] DL-PA 0~15 12 FIX Y-DELAY TIME FOR SECAM (AV) [YD] DL-SA 0~15 15 FIX Y-DELAY TIME FOR N358 (AV) [YD] DL-3A 0~15 12 FIX Y-DELAY TIME FOR N443 (AV) [YD] DL-4A 0~15 12 FIX Y-DELAY TIME FOR B/W (AV) [YD] DL-AV 0~15 12 FIX COLOUR OFFSET (PAL) COL-OP 0~15 8 FIX COLOUR OFFSET (SECAM) COL-OS 0~15 8 FIX COLOUR OFFSET (NTSC358) COL-03 0~15 4 FIX COLOUR OFFSET (NTSC443) COL-O4 0~15 4 FIX SHARPNESS OFFSET (PAL) SHP-OP 0~15 8 FIX SHARPNESS OFFSET (SECAM) SHP-OS 0~15 4 FIX SHARPNESS OFFSET (NTSC358) SHP-O3 0~15 12 FIX SHARPNESS OFFSET (NTSC443) SHP-O4 0~15 8 FIX

0~99 OR>99FOR NONE

INITIAL DATA

255 FIX

FIX/ADJ REMARK

(DRI-BS)SAME DATA

14GT15 14GT20

EEPROM ITEMS OSD DATA LENGTH

VERTICAL SCAN DISABLE VSD BLACK STRETCH BKS AUTOMATIC VOLUME LEVELING AVL FAST FILTER IF-PLL FFI ENABLE VERTICAL GUARD (RGB BLANKING) EHT TRACKING MODE (HCO) EHT OVERSCAN SWITCH OFF OSO AUTO COLOUR LIMIT ACL FORCED COLOUR LIMIT FCO SOUND SYSTEM M S-M SOUND SYSTEM DK S-DK SOUND SYSTEM I S-I SOUND SYSTEM BG S-BG PLAYBACK SECAM P-SECAM FE (RF) NTSC 3.58 F-N358 FE (RF) NTSC 4.43 F-N443 FE (RF) SECAM F-SECAM VIDEO MUTE AT IDENT LOSS VMI VIDEO MUTE AT PROGRAM/SOURCE CHANGE HOTEL MODE HTL REDUCED FM DEMODULATOR GAIN FOR BTSC SIGNAL NUMBER OF EXTERNAL AV SOURCE AV FM WINDOW SELECTION FMWS SOUND MUTE BIT 0 SM0 SOUND MUTE BIT 1 SM1 THAI LANGUAGE THA ARABIC LANGUAGE ARA MALAY LANGUAGE MAL CHINESE LANGUAGE CHI FRENCH LANGUAGE FRE RUSSIAN LANGUAGE RUS FORCED V-SYNC SLICING LEVEL FSL SYNC OF OSD HP2 TUNER CPT CPT BILINGUAL BIL IF AGC SPEED BIT 0 AGC0 IF AGC SPEED BIT 1 AGC1 PHI-1 TIME CONSTANT (RF) FOA-FE PHI-1 TIME CONSTANT (RF) FOB-FE PHI-1 TIME CONSTANT (OFF AIR) FOA-AV PHI-1 TIME CONSTANT (OFF AIR) FOB-AV

EVG

VMC

BTSC

0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE)

0 FOR1 AV/1 FOR 2AV 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE)

0(BRAZIL)/1(ARGENTINA)

0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE) 0(DISABLE)/1(ENABLE)

INITIAL DATA

0 FIX 1 FIX 1 FIX 0 FIX 1 FIX ONLY BLK 1 FIX 0 FIX 0 FIX 0 FIX 0 FIX 1 FIX *1 1 FIX *1 1 FIX 1 FIX *1 0 FIX 1 FIX *1 1 FIX *1 1 FIX 1 FIX 0 FIX 0 FIX 1 FIX *2 0 FIX 1 FIX 0 FIX 0 FIX *3 1 FIX *4 1 FIX *4 1 FIX *4 1 FIX *4 1 FIX *4 0 FIX 0 FIX 0 FIX 0 FIX 1 FIX 0 FIX 0 FIX 0 FIX 1 FIX 1 FIX

FIX/ADJ REMARK

NOTE :

FIXED DATA,PLEASE DO NOT CHANGE WITHOUT SPECIFIC INSTRUCTION. *1: MANUALLY CHANGE TO 0. *2: FOR 14GT15, MANUALLY CHANGE TO 0. *3: MANUALLY CHANGE TO 1. *4: MANUALLY CHANGE TO 0.

14GT15 14GT20

SHIPPING SETTING & CHECKING

(1) The following default data has been factory-set for the E2PROM.

ITEMS DATA SETTING

LAST PROGRAM/CHANNEL 1 FLASHBACK PROGARM/CH 1

DIGIT 1 C-SYSTEM AUTO S-SYSTEM B/G

SKIP OFF

AFC ON

VOLUME 1

CONTRAST 60 (MAX)

COLOUR 0 (CENTER)

BRIGHTNESS 0 (CENTER)

TINT 0 (CENTER) SHARPNESS 0 (CENTER) WHITE TEMP ST ANDARD

REMINDER TIMER In-active, "--:--"

ON TIMER In-active, "--:--"

OFF TIMER In-active, "--:--"

LAST POWER POWER-ON

LANGUAGE ENGLISH

BLUE BACK MUTE OFF

HOTEL MODE OFF

0 CHANNEL SKIP ON

AFTER PRESSING MODEL SETTING, 0 CHANNEL WILL BE SKIPPED.

PIF ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

Tuner IFT

1 1. Get the tuner ready to receive the CH. E - 9

( PRESET )

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.

Oscilloscope

1000p

10k

100k

1n60

75ohm

Fig.1

E-9 CH

P C

-1.5+/-0.8dB

14GT15 14GT20

IF OUT

RF-AGC

TAKE OVER POINT ADJUSTMENT (I2C BUS CONTROL)

Note: Be sure to keep the tuner cover in position

during this adjustment.

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

TP201+

–

Bias box

TV Set

–

» Bias box: About 4.5 V

Fig. 3

3. Call "AGC" mode in service mode. Adjust the "AGC" bus data to obtain the Tuner output pin drop 0.1V 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.

Fig.2

Note: For the 50 ohm signal

strength gauge, when not using 50/75 impedance adapter, signal strength is 52±1dBµV(75 ohm open), in- stead of 57±1dBµV (75 ohm open).

Precaution: The loss of using

impedance adapter

14GT15 14GT20

PURITY ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

PURITY ADJ. 1. Receive the GREEN-ONLY signal. Adjust the

beam current to about 500 µA.

2. Maintain the purity magnet at the zero magnetic field and keep the static convergence roughly adjusted.

3. Observe the points a, b as shown in Fig. 4-1 through the microscope. Adjust the landing to the A rank requirements.

4. Orient the raster rotation to 0 eastward.

5. Tighten up the deflection coil screws. » Tightening torque: 108 ± 20 N (11 ± 2 kgf)

6. 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 500 µA.

Fig. 4-1

A = B

Fig. 4-2

Rank "A"

(on the right of the CRT)

A = B

Fig. 4-3

Rank "A"

(on the left of the CRT)

CONVERGENCE ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

14GT15 14GT20

CONVERGENC

ADJ. ( To be done after the purity adjustment.

1. Receive the "Crosshatch Pattern" signal.

2. Using the remote controller, call NORMAL mode.

STATIC CONVERGENCE

1. Turn the 4-pole magnet to a proper opening angle in order to superpose the blue and red colours.

2. Turn the 6-pole magnet to a proper opening angle in order to superpose the green colour over the blue and red colours.

DYNAMIC CONVERGENCE

1. Adjust the convergence on the fringes of the screen in the following steps. a) Fig. 5-1: Drive the wedge at point "a" and swing

the deflection coil upward.

b) Fig. 5-2: Drive the wedge at points "b" and "c"

and swing the deflection coil downward.

c) Fig. 5-3: Drive the "c" wedge deeper and swing

the deflection coil rightward.

d) Fig. 5-4: Drive the "b" wedge deeper and swing

the deflection coil leftward.

2. Fix all the wedges on the CRT and apply glass tape over them.

3. Apply lacquer to the deflection yoke lock screw, magnet unit (purity, 4-pole, 6-pole magnets) and magnet unit lock screw.

BGR

B G R

Fig. 5-1

RGB

R G B

Fig. 5-2

B G R

Fig. 5-3

R G B

RGB

BGR

Finally received the Red-only and Blue-only signals to make sure there is no other colours on the screen.

About 100°

Lacquer

Wedge "b"

4-pole magnet

Lacquer

Purity magnet

Fig. 5-4

Wedge "a"

About 100°

Wedge "c"

6-pole magnet

CRT neck

40cm

14GT15

1 2 3 4 5

14GT20

CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

CRT CUTOFF

ADJUSTMENT (I2C BUS CONTROL)

1. Switch TV to VIDEO mode,BLUE BACK OFF , with NO VIDEO signal.

2. Press R/C to set Picture Normal condition.

3. Connect the oscilloscope to Red OUT from

3.0Vdc

IC801.(TP851)

Range : 1 V/Div (DC) Sweep : 5 msec/Div

1 V

SUB-BRIGHT-

NESS ADJUSMENT (I2C BUS CONTROL)

4. Adjust SCREEN VR ,so that the tip of signal reach

3.0 Vdc + 0.1 Vdc.

1. Call " SUB-BRI" in service mode. (Receive Crosshatch pattern with 5 black level windows)

2. Adjust the " SUB BRIGHT " bus data in order that the line 1, 2 and 3 have the same darkness whereas line 4 is slightly brighter than line 1, 2

and 3 and finally line 5 will be the brighter than line 4.

WHITE BAL-

3 * 12300°K X: 0.272

ANCE SERVICE MODE ADJ. (I2C BUS CONTROL)

1. Receive the "WHITE" pattern with BURST signal.

2. Press R/C to set Picture NORMAL condition.

3. Connect the DC miliammeter between TP602 (-) and TP603 (+).

4. Check Beam current should be around 800 µA.

5. Set it to service mode and adjust the " WPG" (WhitePoint-G), "WPB" (White Point-B) data to

1, 2, 3 are in same black level.

Y: 0.275

(MINOLTA COLOUR ANALYZER CA-100) *Note: Above Data can be UP/

DOWN by Volume key. have a colour temperature of 12,300°K ( white ). * Note .

6. Receive "WHITE" pattern, with BURST signal, and set Brightness Y by generator, to **10cd/m

Minolta CA-100) by reducing Luminate Y signal.

7. Adjust "CUT-R" & "CUT-G" to get 12,300°K . Then go back normal mode. (High Bright)** to check colour temperature. If out of range, back to 1.

Maximum beam check

Note: This adjustment must be done after

warming up the unit for 30 minutes or longer with a beam current over 500µA).

* Adjust DRI-GC/GW, DRI-BC/BW as following

data, after finishing DRI-GS and DRI-BS: DRIGC=DRI-GW="DRI-GS"-7:DRI-BW="DRI-BS"7:DRI-RC=25:DRI-BC=DRI-BS:DRI-RW=32

** Low=10cd/m2:High=200cd/m

1. Receive the "Monoscope Pattern" signal.

2. Press R/C to set Picture NORMAL condition.

3. Connect the DC miliammeter between TP603 (+) and TP602 (–). (Full Scale: 3 mA Range)

4. Beam current must be within 800 ± 100 µA.

14GT15

Y 100%W

75%

Mg R

14GT20

HORIZONTAL AND VERTICAL DEFLECTION LOOP ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

V-SLOPE (I2C

BUS CONTROL)

V-SHIFT 50

(I2C BUS CONTROL)

V - AMP 50 (I2C BUS CONTROL)

S-CORRECTION (I2C BUS CONTROL)

H - SHIFT (50)

(H-CENTER) (I2C BUS CONTROL)

SUB-SHARP-

NESS

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 button.

Focus 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.

PAL CHROMA ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

SUB COLOUR

(I2C 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(TP854).

» Range : 20 V/div. (AC) (Using 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 P AL Colour Bar be at the same level shown as Fig. 8.

5. Clear the SERVICE mode.

Fig. 8

14GT15 14GT20

NTSC CHROMA ADJUSTMENT

No. Adjusting point Adjusting procedure/conditions Waveform and others

SUB-TINT (I2C

BUS CONTROL)

1. Receive the "NTSC3.58 Colour Bar" signal through A V 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.

(SAME LEVEL)

WYCy G Mg R

Fig. 9

PROTECTOR OPERATION CHECKING

No. Adjusting point Adjusting procedure/conditions Waveform and others

BEAM PRO-

1 * Select one of Q883/5/7 to do

TECTOR

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.

each short test.

H, V PROTEC-

TOR

Other

protectors

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.

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)

A/V INPUT AND OUTPUT CHECKING

No. Adjusting point Adjusting procedure/conditions Waveform and others

VIDEO AND

AUDIO OUTPUT CHECK

1. Receive the "PAL Color Bar" signal (100% White Color Bar, Sound 400 Hz 100% Mod.)

2. Terminate the V ideo output with a 75 ohm impedance. Make sure the output is as specified (1.0 Vp-p ±3 dB).

3. Terminate the Audio output with a 10k ohm impedance. Make sure the output is as specified (1.76 Vp-p ±3 dB).

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, A V1, AV2 & TV again and the video & audio output are according to the input terminal for each mode.

FUNCTION OPERATION CHECKING (VIDEO AND AUDIO)

No. Adjusting point Adjusting procedure/conditions Waveform and others

14GT15 14GT20

CONTRAST

key

COLOUR key

BRIGHTNESS

key

TINT key 1. Receive the "NTSC Colour Bar" signal thru AV in.

1. Receive "Monoscope Pattern" signal.

2. Set P-Mode to select CONTRAST.

3. Press Volume Up/Down key to check whether the CONTRAST effect is OK or not.

1. Receive "Color Bar" signal.

2. Set P-Mode to select COLOUR.

3. Press Volume Up/Down key to check whether the COLOUR effect is OK or not.

1. Receive "Monoscope Pattern" signal.

2. Set P-Mode to select BRIGHTNESS.

3. Press Volume Up/Down key to check whether the BRIGHTNESS effect is OK or not.

2. Set P-Mode to select TINT.

3. Press Volume Up/Down key to check TINT, UP for GREEN direction and DOWN for PURPLE direction whether is OK or not.

SHARPNESS

Key

CH DISPLAY

COLOUR

NORMAL Key7

WHITE TEMP 1. Receive "Monoscope Pattern" signal.

1. Receive "Monoscope Pattern" signal.

2. Set P-mode to select SHARPNESS.

3. Press Volume Up/Down key to check whether the SHARPNESS effect is OK or not.

1. All Ch (1~99) will have an OSD display of the channel number in green colour under AFT ON condition.

1. Once in PICTURE Mode, and the NORMAL key is pressed, all the settings will be present to normal setting. (Normal setting value for every mode).

» CONTRAST : MAX » COLOUR : CENTER » BRIGHTNESS : CENTER » TINT : CENTER » SHARPNESS : CENTER

2. Set FUNCTION to select WHITE TEMP.

3. Press Volume Up/Down key to check WHITE TEMP Option, STANDARD: NORMAL SETTING, WARM for more REDDISH direction changing, COOL for more BLUISH direction changing.

Notes:If nothing is display

mean contrast, colour, bright, tint, sharpness are all in normal setting.

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