JVC AV-21F8 Schematic

SERVICE MANUAL

COLOUR TELEVISION

AV-21F8(VT)

AV-21F8

BASIC CHASSIS

CL-M

++−

−

CONTENTS

■ SPECIFICATIONS ........................................................................................................................... 2

■ SAFETY PRECAUTIONS ................................................................................................................ 3

■ FEATURES ...................................................................................................................................... 4

★ OPERATING INSTRUCTIONS (APPENDED).............................................................................. 1-1

■ SPECIFIC SERVICE INSTRUCTIONS ............................................................................................ 4

■ SERVICE ADJUSTMENTS........................................................................................................... .10

★ STANDARD CIRCUIT DIAGRAM (APPENDED) ......................................................................... 2-1

■ PARTS LIST................................................................................................................................... 27

No. 56036 1

No. 56036

Jun. 2000

AV-21F8

SPECIFICATIONS

Item Content

Dimensions (W × H × D) 619mm × 458mm × 486.5mm Mass 22kg TV RF System B / G, D / K, K1, M Colour System TV Mode PAL / SECAM / NTSC3.58 / NTSC4.43

VIDEO Mode PAL / SECAM / NTSC3.58 / NTSC4.43

Receiving Frequency VHF (VL) 46.25MHz ~ 168.25MHz

VHF (VH) 175.25MHz ~ 463.25MHz UHF 471.25MHz ~ 863.25MHz CATV ● Cable TVs of Mid (X-Z, S1-S10)

Super (S11-S20) & Hyper (S21-S41) bands receivable

Intermediate VIF Carrier 38.0MHz Frequency 31.5MHz (6.5MHz)

SIF Carrier 32.5MHz (5.5MHz)

33.5MHz (4.5MHz)

Colour Sub Carrier Frequency PAL (4.43MHz), SECAM (4.40625MHz / 4.25MHz)

NTSC (3.58MHz / 4.43MHz)

Aerial Input Terminal 75Ω Unbalanced Power Input Rating: AC110 ~ 240V, 50/60Hz Operating: AC90 ~ 260V, 50/60Hz Power Consumption 110W (Max.) / 78W (Avg.) Picture Tube Visible size : 51cm measured diagonally High Voltage 28kV ± 1kV (at zero beam current) Speaker 6cm × 12 cm Oval type × 2 Audio Output 5W + 5W Input Video 1Vp-p, 75Ω

Audio (L/R) 500mVrms (−4dBs), High impedance

Output Video 1Vp-p, 75Ω

Audio (L/R) 500mVrms (–4dBs), Low impedance

Remote Control Unit RM-C218-1C (Battery size : AA/R06/UM-3 × 2)

Design & specifications are subject to change without notice.

No. 560362

SAFETY PRECAUTIONS

AC VOLTMETER (HAVING 1000Ω/V, OR MORE SENSITIVITY)

PLACE THIS PROBE ON EACH EXPOSED METAL PART

1500Ω 10W

0.15µF AC-TYPE

GOOD EARTH GROUND

AV-21F8

1. The design of this product contains special hardware, many circuits and components specially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel only.

2. Alterations of the design or circuitry of the products should not be made. Any design alterations or additions will void the manufacturer's warranty and will further relieve the manufacturer of responsibility for personal injury or property damage resulting therefrom.

3. Many electrical and mechanical parts in the products have special safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in the parts list of Service manual. Electrical

components having such features are identified by shading on the schematics and by (!) on the parts list in Service manual. The use of a substitute replacement which does

not have the same safety characteristics as the recommended replacement part shown in the parts list of Service manual may cause shock, fire, or other hazards.

4. Don't short between the LIVE side ground and ISOLATED

(NEUTRAL) side ground or EARTH side ground when repairing.

Some model's power circuit is partly different in the GND. The difference of the GND is shown by the LIVE : (#) side GND, the ISOLATED (NEUTRAL) : (") side GND and EARTH : ($) side GND. Don't short between the LIVE side GND and ISOLATED (NEUTRAL) side GND or EARTH side GND and never measure with a measuring apparatus (oscilloscope etc.) the LIVE side GND and ISOLATED (NEUTRAL) side GND or EARTH side GND at the same time. If above note will not be kept, a fuse or any parts will be broken.

5. If any repair has been made to the chassis, it is recommended that the B1 setting should be checked or adjusted (See ADJUSTMENT OF B1 POWER SUPPLY).

6. The high voltage applied to the picture tube must conform with that specified in Service manual. Excessive high voltage can cause an increase in X-Ray emission, arcing and possible component damage, therefore operation under excessive high voltage conditions should be kept to a minimum, or should be prevented. If severe arcing occurs, remove the AC power immediately and determine the cause by visual inspection (incorrect installation, cracked or melted high voltage harness, poor soldering, etc.). To maintain the proper minimum level of soft XRay emission, components in the high voltage circuitry including the picture tube must be the exact replacements or alternatives approved by the manufacturer of the complete product.

8. When service is required, observe the original lead dress. Extra precaution should be given to assure correct lead dress in the high voltage circuit area. Where a short circuit has occurred, those components that indicate evidence of overheating should be replaced. Always use the manufacturer's replacement components.

9. Isolation Check

(Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an isolation check on the exposed metal parts of the cabinet (antenna terminals, video/audio input and output terminals, Control knobs, metal cabinet, screw heads, earphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.

(1) Dielectric Strength Test

The isolation between the AC primary circuit and all metal parts exposed to the user, particularly any exposed metal part having a return path to the chassis should withstand a voltage of 3000V AC (r.m.s.) for a period of one second.

(. . . . Withstand a voltage of 1100V AC (r.m.s.) to an appliance

rated up to 120V, and 3000V AC (r.m.s.) to an appliance rated 200V or more, for a period of one second.) This method of test requires a test equipment not generally found in the service trade.

(2) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use a line isolation transformer during this check.). Using a "Leakage Current Tester", measure the leakage current from each exposed metal part of the cabinet, particularly any exposed metal part having a return path to the chassis, to a known good earth ground (water pipe, etc.). Any leakage current must not exceed

0.5mA AC (r.m.s.). However, in tropical area, this must not exceed 0.2mA AC (r.m.s.).

● Alternate Check Method Plug the AC line cord directly into the AC outlet (do not use a line isolation transformer during this check.). Use an AC voltmeter having 1000 ohms per volt or more sensitivity in the following manner. Connect a 1500Ω 10W resistor paralleled by a

0.15µF AC-type capacitor between an exposed metal part and a known good earth ground (water pipe, etc.). Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly any exposed metal part having a return path to the chassis, and measure the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Any voltage measured must not exceed 0.75V AC (r.m.s.). This corresponds to 0.5mA AC (r.m.s.). However, in tropical area, this must not exceed 0.3V AC (r .m.s.). This corresponds to 0.2mA AC (r.m.s.).

7. Do not check high voltage by drawing an arc. Use a high voltage meter or a high voltage probe with a VTVM. Discharge the picture tube before attempting meter connection, by connecting a clip lead to the ground frame and connecting the other end of the lead through a 10kΩ 2W resistor to the anode button.

No. 56036 3

AV-21F8

FEATURES

● New chassis design enables use of an interactive on-screen control.

● Wide range voltage for AC power input.

● With AUDIO / VIDEO INPUT & OUTPUT terminals.

● MUTING button can reduce the audio level to zero instantly.

● Functional remote control to operate TV set (for channel select, volume control, power ON/OFF, etc.) from a distance.

C bus control utilizes single chip ICs for IF, V/C (Video/Chroma) and VSM (Video Status Memory).

● I

● By means of AUTO PROGRAM, the TV stations can be selected automatically and the TV channels can also be rearranged

automatically.

● Built-in ECO MODE (ECONOMY, ECOLOGY) In accordance with the brightness in a room, the brightness and/or contrast of the picture can be adjusted automatically to make the optimum picture which is easy on the eye.

● Built-in ON TIMER & RETURN +.

SPECIFIC SERVICE INSTRUCTIONS

DISASSEMBLY PROCEDURE

REMOVING THE REAR COVER

1. Unplug the AC power cord.

2. Remove the 6 screws marked "A" and 2 screws marked "B".

3. Withdraw the rear cover backward.

REMOVING THE MAIN PW BOARD

● After removing the rear cover.

1. Slightly raise both sides of the Main PW Board by hand and

withdraw it backward. (If necessary, take off the wire clamp, connectors etc.)

REMOVING THE SPEAKER

● After removing the rear cover.

1. Remove the 2 screws marked "C".

2. Follow the same step for removing the other hand speaker.

CHECKING THE MAIN PW BOARD

T o check the back side of the Main PW Board, follow the next steps.

1. Pull out the Main PW Board. (Refer to "REMOVING THE MAIN

PW BOARD".)

2. Erect the Main PW Board vertically so that you can easily check

its back side.

CAUTION:

● When erecting the Main PW Board, be careful so that there will

be no contacting with other PW Board.

● Before turning on power, make sure that all connectors are prop-

erly connected.

WIRE CLAMPING AND CABLE TYING

1. Be sure to clamp the wire.

2. Never remove the cable tie used for tying the wires together.

Should it be inadvertently removed, be sure to tie the wires with a new cable tie.

No. 560364

FRONT CABINET

SPEAKER

CRT SOCKET PWB

AV-21F8

(×2)

MAIN PWB

SPEAKER

(×2)

REAR COVER

(×2)

(×6)

No. 56036 5

AV-21F8

SYSTEM CONSTANT - I

SYSTEM CONSTANT SET 1/3

SYSTEM CONSTANT - II

SYSTEM CONSTANT SET 2/3

− / + : OPERATE

DISP : EXIT

− / + : OPERATE

DISP : EXIT

11. LANGUAGE : E/V

12. TUNER : MU

13. AMP TUNER : YES

14. VNR : NO

SYSTEM CONSTANT - III

SYSTEM CONSTANT SET 3/3

− / + : OPERATE

DISP : EXIT

Fig. 2

a: SELECT

6. SPATIALIZER : YES

7. VOL. LIMITER : YES

8. B/B SOUND : NO

9. TEXT : NO

10. COLOUR AUTO : NO

1. INCH : 21

2. COLOUR : MULTI

3. VIDEO INPUT : 1

4. ECO SENSOR : YES

5. SUPER BASS : NO

REPLACEMENT OF MEMORY IC

1. MEMORY IC

This TV uses the following memory IC.

Memory IC: IC1702 on MAIN PW Board

The memory IC memorizes data for correctly operating the video and deflection circuits. When replacing the memory IC, be sure to use the same type IC written with the initial values of data. In other words, use the specific IC listed in "PRINTED WIRING BOARD PARTS LIST". For its mounting location, refer to "ADJUSTMENT LOCATIONS".

2. PROCEDURE FOR REPLACING MEMORY IC

(1) Power off

Switch the power off and unplug the power cord from the wall outlet.

(2) Replacing the memory IC

Replace the memory IC with new one. Be sure to use the memory IC written with the initial data values.

(3) Power on

Plug the power cord into the wall outlet and switch the power on.

(4) Check and setting of SYSTEM CONSTANT SET:

1) Press the DISPLAY key and the PICTURE MODE key on the remote control unit simultaneously. The SERVICE MENU screen will be displayed. (See Fig. 1.)

2) In the SERVICE MENU, press the DISPLAY key and PICTURE MODE key simultaneously. Then, the SYSTEM CONSTANT SET screen will be displayed. (See Fig. 2.)

3) Check whether the setting values of the SYSTEM CONSTANT SET are the same as those indicated in Table

1. If the value is different, select the setting item with the MENU a key, and set the correct value with the MENU − / + key.

4) Press the DISPLAY key twice to return to the normal screen.

(5) Receive channel setting

Refer to the OPERATING INSTRUCTIONS and set the receive channels (channels preset).

(6) User setting

Check the user setting values in Table 2, and if setting value is different, set the correct value. For setting, refer to the OPERATING INSTRUCTIONS.

(7) Setting of SERVICE MENU

Verify the setting for each setting item in the SERVICE MENU. (See Table 3.) If readjustment is necessary, perform adjustment referring to "SERVICE ADJUSTMENTS".

SERVICE MENU

1. IF

3. VSM PRESET

1-3 : SELECT DISP : EXIT

✽✽✽✽✽✽✽✽ ✽✽✽✽✽

2. V/C

✽✽.✽✽✽✽

✽✽✽ ✽✽✽✽✽

Fig. 1

✽✽.✽✽✽✽

No. 560366

NAME OF REMOTE CONTROL KEYS

DISPLAY

PICTURE MODE

AV-21F8

DISPLAY

−

LIVE

SPATIAL

CHANNEL

SYSTEM

COLOUR

SOUND

TV/VIDEO

PICTURE MODE

RETURN+

CHANNEL SCAN

ECO SENSOR OFF TIMER

POWER

−

VOLUME

PICTURE

MUTING

BOOSTER

123

456

7809

-/--

SETTING OF SYSTEM CONSTANT SET

Table 1

Setting item Setting contents Setting value

1. INCH 21

2. COLOUR MULTI

3. VIDEO INPUT 1

4. ECO SENSOR YES

5. SUPER BASS NO

6. SPATIALIZER YES

7. VOL. LIMITER YES

8. B/B SOUND NO

9. TEXT NO

10. COLOUR AUTO NO

11. LANGUAGE E/V

12. TUNER MU

13. AMP TUNER YES

14. VNR NO

29 25 21 14 MULTI. TRIPLE PAL 13 YES NO YES NO YES NO YES NO YES NO YES NO YES NO E E/V MU MA YES NO YES NO

RM-C234 REMOTE CONTROL UNIT

USER SETTING VALUES

Table 2

Setting item Setting value Setting item Setting value

SUB POWER ON BASS CENTER CHANNEL POSITION 1 POSITION BALANCE CENTER CHANNEL PRESET Refer to OPERATING INSTRUCTION. OFF TIMER OFF VOLUME Appropriate sound volume AUTO SHUTOFF OFF TV/VIDEO TV ECO SENSOR OFF ON SCREEN DISPLAY POSITION NUMBER DISPLAY LANGUAGE VIETNAMESE COLOUR SYSTEM PAL BLUE BACK OFF SOUND SYSTEM B / G ON TIMER PR1 0:00 PICTURE MODE (VSM) BRIGHT CHILD LOCK OFF LIVE SPATIAL OFF PICTURE BOOSTER OFF TREBLE CENTER

No. 56036 7

AV-21F8

SERVICE MENU SETTING ITEMS

Table 3

Service menu Setting item

1. IF 1. VCO

2. DELAY POINT

2. V / C 1. CUTOFF(R/G/B)

2. DRIVE(R/B)

3. BRIGHT

4. CONT.

5. COLOUR

6. TINT (TV/VIDEO)

7. BLACK OFFSET(R-Y/B-Y)

8. SHARP

9. TEXT(RGB)CONT.

10. H. CENTER

11. V. HEIGHT

12. V. LIN

13. V.S-CR

14. V. CENTER

15. AMP T . SHARP

Do not adjust.

Service menu Setting item

3. VSM PRESET TINT (BRIGHT/STD/SOFT) COLOUR

BRIGHT CONT. SHARP

Do not adjust.

No. 560368

REPLACEMENT OF CHIP COMPONENT

■ CAUTIONS

1. Avoid heating for more than 3 seconds.

2. Do not rub the electrodes and the resist parts of the pattern.

3. When removing a chip part, melt the solder adequately.

4. Do not reuse a chip part after removing it.

■ SOLDERING IRON

1. Use a high insulation soldering iron with a thin pointed end of it.

2. A 30W soldering iron is recommended for easily removing parts.

■ REPLACEMENT STEPS

1. How to remove Chip parts

● Resistors, capacitors, etc.

(1) As shown in the figure, while pushing the chip part with twee-

zers, alternately melt the solder at its each end.

AV-21F8

2. How to install Chip parts

● Resistors, capacitors, etc.

(1) Apply solder to the pattern as indicated in the figure.

(2) Shift the chip part with tweezers and remove it.

● Transistors, diodes, variable resistors, etc.

(1) Apply extra solder to each lead.

SOLDER

(2) As shown in the figure, while pushing the chip part with twee-

zers, alternately melt the solder at its each lead. Then, shift and remove the chip part.

SOLDER

(2) Grasp the chip part with tweezers and place it on the solder.

Then heat and melt the solder at both ends of the chip part.

● Transistors, diodes, variable resistors, etc.

(1) Apply solder to the pattern as indicated in the figure. (2) Grasp the chip part with tweezers and place it on the solder. (3) First solder lead A as indicated in the figure.

(4) Then solder leads B and C.

Note : After removing the part, remove remaining solder from

the pattern.

No. 56036 9

AV-21F8

SERVICE ADJUSTMENTS

BEFORE STARTING SERVICE ADJUSTMENT

1. There are 2 ways for adjusting this TV: One is with the REMOTE CONTROL UNIT and the other is the conventional method using adjustment parts and components.

2. The setting (adjustment) using the REMOTE CONTROL UNIT is made on the basis of the initial setting values. The setting values which adjust the screen to the optimum condition can be different from the initial setting values.

3. Make sure that connection is correctly made to AC power source.

4. Turn on the power of the TV and measuring instrument for warming up for at least 30 minutes before starting adjustment.

5. If the receive or input signal is not specified, use the most appropriate signal for adjustment.

6. Never touch parts (such as variable resistors, transformers and capacitors) not shown in the adjustment items of this service adjustment.

7. Preparation for adjustment (presetting): Unless otherwise specified in the adjustment items, preset the following functions with the remote control unit.

PICTURE MODE (VSM) COLOUR/BRIGHT/CONT./SHARP

OFF TIMER ECO SENSOR BLUE BACK PICTURE BOOSTER

Function

Setting value

BRIGHT See "VSM Preset" on page 23.

OFF OFF OFF OFF

MEASURING INSTRUMENT

ADJUSTMENT/CHECK ITEMS

AND FIXTURES

Adjustment/Check item Page

1. DC voltmeter (or Digital voltmeter)

2. Oscilloscope

3. Signal generator (Pattern generator) [PAL / SECAM / NTSC]

4. Remote control unit

B1 POWER SUPPLY Check 14 FOCUS Adjustment 14 IF CIRCUIT Adjustment 14 V/C (VIDEO/CHROMA) CIRCUIT Adjustment 15 DEFLECTION CIRCUIT Adjustment 21 VSM PRESET Adjustment 23 PURITY, CONVERGENCE Adjustment 24

BASIC OPERATION IN SERVICE MENU

1. TOOL OF SERVICE MENU OPERATION

Operate the SERVICE MENU with the remote control unit.

2. SERVICE MENU ITEMS

With the SERVICE MENU, various settings (adjustments) can be made, and they are broadly classified in the following items of settings:

● 1. IF ............................. For entering/adjusting the setting values (adjustment values) of the IF circuit.

● 2. V/C........................... For entering/adjusting the setting values (adjustment values) of the VIDEO/CHROMA and DEFLECTION cir-

● 3. VSM PRESET ......... For setting the values of STANDARD, SOFT and BRIGHT

cuits.

(VSM: video status memory)

No. 5603610

AV-21F8

3. BASIC OPERATION IN SERVICE MENU (1) How to enter SERVICE MENU

Press the DISPLAY key and the PICTURE MODE key on the remote control unit simultaneously. The SERVICE MENU screen will be displayed. (See Fig. 1.)

(2) Selection of SUB MENU SCREEN

Press one of the keys 1 ~ 3 on the remote control unit, and select the SUB MENU SCREEN from the SERVICE MENU. (See Fig. 2.)

SERVICE MENU → SUB MENU 1. IF

2. V / C

3. VSM PRESET

SUB MENU SCREEN

SERVICE MENU

1. IF

3. VSM PRESET

1-3 : SELECT DISP : EXIT

✽✽✽✽✽✽✽✽ ✽✽✽✽✽

✽✽✽ ✽✽✽✽✽

2. V/C

✽✽.✽✽✽✽

SUB MENU 1. IF

1. VCO

2. DELAY POINT

1-2 : SELECT DISP : EXIT

SERVICE MENU

1. IF

3. VSM PRESET

1-3 : SELECT DISP : EXIT

✽✽✽✽✽✽✽✽ ✽✽✽✽✽

2. V/C

✽✽.✽✽✽✽

✽✽✽ ✽✽✽✽✽

Fig. 1

VCO (CW)

TOO HIGH ABOVE REFERENCE BELOW REFERENCE TOO LOW

✽✽.✽✽✽✽

✽✽✽.✽✽ MHz

DISP : EXIT

SUB MENU 2. V/C

V/C

1. CUTOFF

50Hz

a : SELECT

− / + : OPERATE

PAL

(R)

✽ ✽✽

(G)

✽ ✽✽ ✽ ✽✽

(B)

DISP : EXIT

SUB MENU 3. VSM PRESET

BRIGHT

TINT COLOUR BRIGHT CONT. SHARP

a : SELECT

− / + : OPERATE

✽✽ ✽✽ ✽✽ ✽✽ ✽✽

DISP : EXIT

DELAY POINT

AGC TAKE-OVER

− / + : OPERATE

Setting item

1. CUTOFF(R/G/B)

2. DRIVE(R/B)

3. BRIGHT

4. CONT.

5. COLOUR

6. TINT (TV/VIDEO)

7. BLACK OFFSET(R-Y/B-Y)

8. SHARP

9. TEXT(RGB)CONT.

BRIGHT / STD / SOFT

Setting item

TINT COLOUR BRIGHT CONT. SHARP

✽✽

DISP : EXIT

Setting item

10. H. CENTER

11. V. HEIGHT

12. V. LIN

13. V.S-CR

14. V. CENTER

15. AMP T. SHARP

Fig. 2

No. 56036 11

AV-21F8

(3) Method of Setting

*Once the setting values are set, they are memorized automatically. *It must not adjust without inputting a signal.

1) 1. IF

[1. VCO]

(a) 1 Key ......................................... Select 1. IF.

(b) 1 Key ......................................... Select 1. VCO. (CW)

(c) VCO(CW) TRANSF. .................. Adjust VCO(CW) while watching the colour (yellow/blue) of the characters on the screen.

(d) DISPLAY Key ............................ When this is pressed twice, you will return to the SERVICE MENU.

[2. DELAY POINT]

(a) 1 Key ......................................... Select 1. IF.

(b) 2 Key ......................................... Select 2. DELAY POINT.

(d) DISPLAY Key ............................ When this is pressed twice, you will return to the SERVICE MENU.

2) 2. V/C and 3. VSM PRESET

(a) 2 and 3 Keys ............................. Select 2. V/C and 3. VSM PRESET.

(b) MENU a key........................ Select setting items.

● Use the number keys on the remote control unit for setting of WHITE BALANCE and BLACK

(d) DISPLAY Key ............................ When this is pressed, you will return to the SERVICE MENU.

OFFSET. For the setting, refer to each item concerned.

(4) Release of SERVICE MENU

After completing the setting, return to the SERVICE MENU by pressing the DISPLA Y key, then again press the DISPLAY key to return to the normal screen.

No. 5603612

ADJUSTMENT LOCATIONS

MAIN PWB

ON TIMER

POWER

ECO SENSOR

VOL-+CH

AV-21F8

FRONT

DEG

S901

POWER SW

REMOCON RECEIVER

F901

TU001

IC701

MEMORY

IC702

IC201

VCO

T101

HVT

CRT SOCKET PWB (SOLDER SIDE)

TP-47G

TP-E

1 Pin TP-91(B1) 2 Pin NC 3 Pin X-ray1 4 Pin X-ray2

5 Pin TP-E

TOP

(")

UPPER : FOCUS LOWER : SCREEN

CRT EARTH (BRAIDED ASS'Y)

No. 56036 13

AV-21F8

ADJUSTMENTS

B1 POWER SUPPLY

Item Test point Adjustment part

Measuring instrument

Check of Signal TP-91 (B1) B1 POWER Generator TP-E (

SUPPLY [S1

DC Voltmeter connector]

FOCUS ADJUSTMENT

Item Test point Adjustment part

Adjustment Signal FOCUS VR of FOCUS generator [In HVT]

Measuring instrument

IF CIRCUIT ADJUSTMENT

Description

1. Receive a whole black signal.

2. Connect a DC voltmeter between TP-91 (B1) and TP-E (") (between pins 1 and 5 of the connector S1).

3. Make sure that the voltage is DC114.5 ± 1.5V.

Description

1. Receive a cross-hatch signal.

2. While watching the screen, adjust the FOCUS VR to make the vertical and horizontal lines as fine and sharp as possible.

3. Make sure that, when the screen is darkened, the lines remain in good focus.

Item Test point Adjustment part

Measuring instrument

Adjustment Remote VCO (CW) of VCO (CW) control unit TRANSF.

[MAIN PWB]

YELLOW

Screen display

VCO (CW) ✽✽✽.✽✽ MHz

TOO HIGH ABOVE REFERENCE BELOW REFERENCE TOO LOW

DISP : EXIT

Step

123 TOO HIGH Yellow Blue Blue ABOVE REFERENCE Blue Yellow Blue BELOW REFERENCE Blue Blue Yellow TOO LOW Blue Blue

Description

● Under normal conditions, no adjustment is required.

1. Select 1. IF from the SERVICE MENU.

2. Press the 1 key to select 1. VCO.

3. Select a receivable broadcast channel with the CHANNEL key .

4. Turn the core of VCO(CW) TRANSF. until the colour of the characters "TOO HIGH" displayed on the screen changes from blue to yellow. (Step 1)

5. Then slowly turn the core of VCO(CW) TRANSF . counterclockwise until the characters "ABOVE REFERENCE" changes from blue to yellow. (Step 2)

6. Further slowly turn the core of VCO(CW) TRANSF. until the colour of the characters "BELOW REFERENCE" changes from blue to yellow. (Step 3)

7. Press the DISPLAY key three times to return to normal screen.

8. Perform CHANNEL PRESET again, and make sure that each broadcast is being received properly.

No. 5603614

AV-21F8

Item Test point Adjustment part

Adjustment Remote DELAY POINT of DELAY control unit (AGC TAKE-OVER) POINT

Setting (Adjustment) item

DELAY POINT (AGC TAKE-OVER)

Measuring instrument

Variable Initial setting range value

0 ~ 63 20

Description

1. Receive a black and white signal (colour off).

2. Select 1. IF from the SERVICE MENU.

3. Select 2. DELAY POINT by pressing the 2 key on the remote control.

4. Adjust the MENU − or + key until video noise disappears.

5. Press the DISPLAY key three times to return to the normal screen.

6. Turn to other channels and make sure that there are no irregularities.

V/C (VIDEO/CHROMA) CIRCUIT ADJUSTMENT

The setting (adjustment) using the remote control unit is made on the basis of the initial setting values. The setting values which adjust the screen to the optimum condition can be different from the initial setting values.

● Do not change the initial setting values of the setting (adjustment) items not listed in "ADJUSTMENT".

[SUB MENU 2. V/C (1. CUT OFF (R / G / B) ~ 9. TEXT (RGB) CONT. and 15. AMP SHARP)]

Colour system Variable Initial setting value

Setting item range PAL SECAM NTSC 3.58 NTSC 4.43

1. CUT OFF (R / G / B) −128 ~ +127 0 b b b

2. DRIVE (R / B) −128 ~ +127 0 b b b

3. BRIGHT −64 ~ +63 −11 b b b

4. CONT. −58 ~ +28 −10 b b b

5. COLOUR −60 ~ +67 +7 +11 +12 −2

6. TINT TV / VIDEO −64 ~ +63 +5 / 0 −2 / 0

7. BLACK OFFSET (R-Y / B-Y) −8 ~ +7 0 / 0

8. SHARP TV / VIDEO −32 ~ +31 +10 / +8 b b b

9. TEXT (RGB) CONT. −128 ~ +127 +15 b b b

15. AMP T. SHARP −128 ~ +127 −15 b b b

: Do not adjust.

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