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AV-20N4
SERVICE MANUAL
COLOUR TELEVISION
BASIC CHASSIS
CG
AV-20N4(BK)
- +
- +
CONTENTS
s SPECIFICATIONS ........................................................................................................................... 2
s SAFETY PRECAUTIONS ................................................................................................................ 3
s FEATURES ...................................................................................................................................... 4
5 OPERATING INSTRUCTIONS (APPENDED) .............................................................................. 1-1
s SPECIFIC SERVICE INSTRUCTIONS ............................................................................................ 4
s SERVICE ADJUSTMENTS ............................................................................................................ 10
5 STANDARD CIRCUIT DIAGRAM (APPENDED) ......................................................................... 2-1
s PARTS LIST ................................................................................................................................... 27
No. 56028
COPYRIGHT © 2000 VICTOR COMPANY OF JAPAN, LTD.
No. 56028 1
Jul. 2000
AV-20N4
SPECIFICATIONS
Item Content
Dimensions (W × H × D) 619mm × 458mm × 488mm
Mass 19kg
TV RF System B / G, I, D / K, K1
Colour System TV Mode PAL / SECAM
VIDEO Mode PAL / SECAM / NTSC3.58 / NTSC4.43
Stereo System Bilingual in A2
Receiving Frequency VHF (VL) 46.25MHz ~ 168.25MHz
VHF (VH) 175.25MHz ~ 463.25MHz
UHF 471.25MHz ~ 863.25MHz
CATV q 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 32.0MHz (6.0MHz)
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 75 Unbalanced
Power Input Rating: AC110 ~ 240V, 50/60Hz Operating: AC90 ~ 260V, 50/60Hz
Power Consumption 62W
Picture Tube Visible size : 48cm measured diagonally
High Voltage 26.5kV ± 1.5kV (at zero beam current)
Speaker 5cm × 12cm Oval type × 2
Audio Output 5W (Monaural)
Input Video 1Vp-p, 75
Audio 500mVrms (-4dBs), High impedance
Output Video 1Vp-p, 75
Audio 500mVrms (4dBs), Low impedance
Headphone Jack Stereo mini jack (3.5ø)
Remote Control Unit RM-C368-1H (Battery size : AA/R06/UM-3 × 2)
Design & specifications are subject to change without notice.
2 No. 56028
AV-20N4
SAFETY PRECAUTIONS
1. The design of this product contains special hardware, many 8. When service is required, observe the original lead dress. Ex-
circuits and components specially for safety purposes. For con- tra precaution should be given to assure correct lead dress in
tinued protection, no changes should be made to the original the high voltage circuit area. Where a short circuit has occurred,
design unless authorized in writing by the manufacturer. Re- those components that indicate evidence of overheating should
placement parts must be identical to those used in the original be replaced. Always use the manufacturer's replacement com-
circuits. Service should be performed by qualified personnel ponents.
only.
9. Isolation Check
2. Alterations of the design or circuitry of the products should not (Safety for Electrical Shock Hazard)
be made. Any design alterations or additions will void the After re-assembling the product, always perform an isolation
manufacturer's warranty and will further relieve the manufac- check on the exposed metal parts of the cabinet (antenna ter-
turer of responsibility for personal injury or property damage minals, video/audio input and output terminals, Control knobs,
resulting therefrom. metal cabinet, screw heads, earphone jack, control shafts, etc.)
to be sure the product is safe to operate without danger of elec-
3. Many electrical and mechanical parts in the products have spe- trical shock.
cial safety-related characteristics. These characteristics are of- (1) Dielectric Strength Test
ten not evident from visual inspection nor can the protection The isolation between the AC primary circuit and all metal parts
afforded by them necessarily be obtained by using replace- exposed to the user, particularly any exposed metal part hav-
ment components rated for higher voltage, wattage, etc. Re- ing a return path to the chassis should withstand a voltage of
placement parts which have these special safety characteris- 3000V AC (r.m.s.) for a period of one second.
tics are identified in the parts list of Service manual. Electrical (. . . . Withstand a voltage of 1100V AC (r.m.s.) to an appliance
components having such features are identified by shad- rated up to 120V, and 3000V AC (r.m.s.) to an appliance rated
ing on the schematics and by (!) on the parts list in Ser- 200V or more, for a period of one second.)
vice manual. The use of a substitute replacement which does This method of test requires a test equipment not generally
not have the same safety characteristics as the recommended found in the service trade.
replacement part shown in the parts list of Service manual may (2) Leakage Current Check
cause shock, fire, or other hazards. Plug the AC line cord directly into the AC outlet (do not use a
line isolation transformer during this check.). Using a "Leakage
4. Don't short between the LIVE side ground and ISOLATED Current Tester", measure the leakage current from each ex-
(NEUTRAL) side ground or EARTH side ground when re- posed metal part of the cabinet, particularly any exposed metal
pairing. part having a return path to the chassis, to a known good earth
Some model's power circuit is partly different in the GND. The ground (water pipe, etc.). Any leakage current must not exceed
difference of the GND is shown by the LIVE : (#) side GND, 0.5mA AC (r.m.s.).
the ISOLATED (NEUTRAL) : (") side GND and EARTH : ($) However, in tropical area, this must not exceed 0.2mA AC
side GND. Don't short between the LIVE side GND and ISO- (r.m.s.).
LATED (NEUTRAL) side GND or EARTH side GND and never q Alternate Check Method
measure with a measuring apparatus (oscilloscope etc.) the Plug the AC line cord directly into the AC outlet (do not use a
LIVE side GND and ISOLATED (NEUTRAL) side GND or line isolation transformer during this check.). Use an AC volt-
EARTH side GND at the same time. meter having 1000 ohms per volt or more sensitivity in the fol-
If above note will not be kept, a fuse or any parts will be bro- lowing manner. Connect a 1500 10W resistor paralleled by a
ken. 0.15µF AC-type capacitor between an exposed metal part and
a known good earth ground (water pipe, etc.). Measure the AC
5. If any repair has been made to the chassis, it is recommended voltage across the resistor with the AC voltmeter. Move the
that the B1 setting should be checked or adjusted (See AD- resistor connection to each exposed metal part, particularly any
JUSTMENT OF B1 POWER SUPPLY). exposed metal part having a return path to the chassis, and
measure the AC voltage across the resistor. Now, reverse the
6. The high voltage applied to the picture tube must conform with plug in the AC outlet and repeat each measurement. Any volt-
that specified in Service manual. Excessive high voltage can age measured must not exceed 0.75V AC (r.m.s.). This corre-
cause an increase in X-Ray emission, arcing and possible com- sponds to 0.5mA AC (r.m.s.).
ponent damage, therefore operation under excessive high volt- However, in tropical area, this must not exceed 0.3V AC (r.m.s.).
age conditions should be kept to a minimum, or should be pre- This corresponds to 0.2mA AC (r.m.s.).
vented. If severe arcing occurs, remove the AC power immedi-
ately and determine the cause by visual inspection (incorrect AC VOLTMETER
installation, cracked or melted high voltage harness, poor sol- (HAVING 1000/V,
dering, etc.). To maintain the proper minimum level of soft X- OR MORE SENSITIVITY)
Ray emission, components in the high voltage circuitry includ-
ing the picture tube must be the exact replacements or alterna-
tives approved by the manufacturer of the complete product.
7. Do not check high voltage by drawing an arc. Use a high volt- 0.15µF AC-TYPE
age meter or a high voltage probe with a VTVM. Discharge the
picture tube before attempting meter connection, by connect- PLACE THIS PROBE
ing a clip lead to the ground frame and connecting the other ON EACH EXPOSED
1500 10W METAL PART
end of the lead through a 10k 2W resistor to the anode but-
ton. GOOD EARTH GROUND
No. 56028 3
AV-20N4
FEATURES
q New chassis design enables use of an interactive on-screen control.
q Wide range voltage for AC power input.
q With AUDIO / VIDEO INPUT & OUTPUT terminals.
q MUTING button can reduce the audio level to zero instantly.
q Functional remote control to operate TV set (for channel select, volume control, power ON/OFF, etc.) from a distance.
q I2C bus control utilizes single chip ICs for IF, V/C (Video/Chroma) and VSM (Video Status Memory).
q By means of AUTO PROGRAM, the TV stations can be selected automatically and the TV channels can also be rearranged
automatically.
q 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.
q Built-in ON TIMER & RETURN +.
SPECIFIC SERVICE INSTRUCTIONS
DISASSEMBLY PROCEDURE
REMOVING THE REAR COVER WIRE CLAMPING AND CABLE TYING
1. Unplug the AC power cord. 1. Be sure to clamp the wire.
2. Remove the 6 screws marked "A" and 1 screw marked "B". 2. Never remove the cable tie used for tying the wires together.
3. Withdraw the rear cover backward. Should it be inadvertently removed, be sure to tie the wires with
a new cable tie.
REMOVING THE MAIN PW BOARD
q 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
q 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
To 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:
q When erecting the Main PW Board, be careful so that there will
be no contacting with other PW Board.
q Before turning on power, make sure that all connectors are prop-
erly connected.
4 No. 56028
AV-20N4
FRONT CABINET
SPEAKER
C (×2)
CRT SOCKET PWB
(Within MAIN PWB)
MAIN PWB
SPEAKER C
(×2)
REAR COVER
B
A (×6)
No. 56028 5
AV-20N4
REPLACEMENT OF MEMORY IC
1. MEMORY IC (6) User setting
This TV uses the following memory IC. Check the user setting values in Table 2, and if setting
Memory IC: IC1702 on MAIN PW Board value is different, set the correct value.
The memory IC memorizes data for correctly operating the For setting, refer to the OPERATING INSTRUCTIONS.
video and deflection circuits. When replacing the memory IC,
be sure to use the same type IC written with the initial values (7) Setting of SERVICE MENU
of data. In other words, use the specific IC listed in "PRINTED Verify the setting for each setting item in the SERVICE
WIRING BOARD PARTS LIST". For its mounting location, re- MENU. (See Table 3.) If readjustment is necessary, per-
fer to "ADJUSTMENT LOCATIONS". form adjustment referring to "SERVICE ADJUSTMENTS".
2. PROCEDURE FOR REPLACING MEMORY IC
SERVICE MENU
(1) Power off
Switch the power off and unplug the power cord from the SERVICE MENU
wall outlet. 1. IF 2. V/C
3. DEF 4. VSM PRESET
(2) Replacing the memory IC 5. PRESET
Replace the memory IC with new one. Be sure to use the 6. TURBO TIMER OFF
memory IC written with the initial data values.
1-6 : SELECT DISP : EXIT
(3) Power on VVVVVVVV VVVVV VV.VVVV
Plug the power cord into the wall outlet and switch the VVV VVVVV VV.VVVV
power on.
Fig. 1
(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 SYSTEM CONSTANT - I
Fig. 1.)
2) In the SERVICE MENU, press the DISPLAY key and SYSTEM CONSTANT SET 1/3
PICTURE MODE key simultaneously. Then, the SYS-
COLOUR : TRIPLE
TEM CONSTANT SET screen will be displayed. (See
BILINGUAL : YES
Fig. 2.) TUNER : MU
3) Check whether the setting values of the SYSTEM CON- ECO SENSOR : YES
STANT SET are the same as those indicated in Table LANGUAGE :E/T
1. If the value is different, select the setting item with
the MENU a key, and set the correct value with a: SELECT
the MENU - / + key. - / + : OPERATE DISP : EXIT
4) Press the DISPLAY key twice to return to the normal
screen.
SYSTEM CONSTANT - II
(5) Receive channel setting
Refer to the OPERATING INSTRUCTIONS and set the SYSTEM CONSTANT SET 2/3
receive channels (channels preset).
B/B SOUND : OFF
LOCK : 180
NAME OF REMOTE CONTROL KEYS COLOUR AUTO : NO
QSS : MINT
ALC : NO
TEXT RATE : 20
ECO PICTURE
SENSOR BOOSTER POWER a: SELECT
- / + : OPERATE DISP : EXIT
SYSTEM PICTURE
COLOUR SOUND MODE
PICTURE
MODE
TV/VIDEO 1 2 3
SYSTEM CONSTANT - III
I / II 4 5 6
SYSTEM CONSTANT SET 3/3
OFF
TIMER 7 8 9
AMP TUNER : YES
CHANNEL
SCAN
RETURN+
0 -/- - VNR : NO
DISPLAY MUTING MENU
DISPLAY
MENU +
- MENU + a: SELECT
MENU - / + : OPERATE DISP : EXIT
MENU
CHANNEL - VOLUME +
Fig. 2
6 No. 56028
AV-20N4
SETTING OF SYSTEM CONSTANT SET
Table 1
Setting item Setting contents Setting value
COLOUR MULTI. TRIPLE PAL TRIPLE
BILINGUAL YES NO YES
TUNER MU MA MU
ECO SENSOR YES NO YES
LANGUAGE E/T E E/T
B/B SOUND ON OFF OFF
YES 10 20 ... 230
LOCK 180
250 240
COLOUR AUTO YES NO NO
QSS MINT MQSS MINT
ALC YES NO NO
TEXT RATE 10 20 40 80 20
AMP TUNER YES NO YES
VNR YES NO NO
USER SETTING VALUES
Table 2
Setting item Setting value Setting item Setting value
SUB POWER ON PICTURE MODE (VSM) BRIGHT
CHANNEL POSITION 1 POSITION OFF TIMER OFF
Refer to OPERATING LANGUAGE THAI
CHANNEL PRESET
INSTRUCTION AUTO SHUTOFF OFF
VOLUME Appropriate sound volume ECO SENSOR OFF
TV/VIDEO TV BLUE BACK OFF
ON SCREEN DISPLAY POSITION NUMBER DISPLAY ON TIMER PR1 0:00
COLOUR SYSTEM AUTO PAL CHILD LOCK OFF
SOUND SYSTEM B/G PICTURE BOOSTER OFF
BILINGUAL MODE I
No. 56028 7
AV-20N4
SERVICE MENU SETTING ITEMS
Table 3
Service menu Setting item Service menu Setting item
1. IF 1. VCO 5. PRESET 1. C-TRAP FIX
2. DELAY POINT 2. SHARP PEAK
3. ABL
4. GAMMA
2. V / C 1. CUTOFF(R/G/B) 5. Y.DELAY TIME
2. DRIVE(R/B) 6. BLACK EXP START
3. BRIGHT 7. C-BPF
4. CONT. 8. CW/SCP
5. COLOUR (P / S/ N3 / N4) 9. V.IF DET. LEVEL
6. TINT (N3 / N4) 10. S.IF DET. LEVEL
7. SECAM BL ADJ 11. IF AGC MIN.
8. SHARP (TV / VIDEO) 12. V.IF AGC
Do not adjust.
9. AMP T. SHARP 13. V.IF PMOD
Do not adjust. 14. S.IF BPF BW ADJUST
15. S.IF TRAP FO ADJUST
16. S.IF TRAP FO ADJUST 2
3. DEF 1. VER. POSITION 17. S.IF-TRAP
2. HOR. POSITION 18. S.IF-BPF
3. VER. HEIGHT 19. VNR
4. VER. LINEARITY 20. RGB LIM.
5. VER. SCURVE 21. RGB LIMIT LEVEL
6. HOR. VCO ADJUST 22. S.IF SW
23. TEXT H. POSITION
Do not adjust.
24. READ DATA
4. VSM PRESET TINT 6. TURBO TIMER ON/OFF
(BRIGHT/STD/SOFT) COLOUR Should be set to OFF.
BRIGHT Do not adjust. (When you turn the TV power off, the
CONT. Turbo Timer is automatically set to
SHARP OFF.)
8 No. 56028
AV-20N4
REPLACEMENT OF CHIP COMPONENT
s 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.
s 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.
s REPLACEMENT STEPS
1. How to remove Chip parts 2. How to install Chip parts
q Resistors, capacitors, etc. q Resistors, capacitors, etc.
(1) As shown in the figure, while pushing the chip part with twee- (1) Apply solder to the pattern as indicated in the figure.
zers, alternately melt the solder at its each end.
(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.
(2) Shift the chip part with tweezers and remove it.
q Transistors, diodes, variable resistors, etc. q Transistors, diodes, variable resistors, etc.
(1) Apply extra solder to each lead. (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.
SOLDER SOLDER
A
(2) As shown in the figure, while pushing the chip part with twee- B
zers, alternately melt the solder at its each lead. Then, shift
and remove the chip part.
C
(4) Then solder leads B and C.
A
B
C
Note : After removing the part, remove remaining solder from
the pattern.
No. 56028 9
AV-20N4
SERVICE ADJUSTMENTS
BEFORE STARTING SERVICE ADJUSTMENT
1. There are 2 ways for adjusting this TV: One is with the 7. Preparation for adjustment (presetting):
REMOTE CONTROL UNIT and the other is the conventional Unless otherwise specified in the adjustment items, preset the
method using adjustment parts and components. following functions with the remote control unit.
2. The setting (adjustment) using the REMOTE CONTROL
UNIT is made on the basis of the initial setting values. The
Function Setting value
setting values which adjust the screen to the optimum con-
dition can be different from the initial setting values. PICTURE MODE (VSM) BRIGHT
3. Make sure that connection is correctly made to AC power source. COLOUR/BRIGHT/CONT./SHARP See "VSM Preset"
4. Turn on the power of the TV and measuring instrument for warm- on page 22.
ing up for at least 30 minutes before starting adjustment. OFF TIMER OFF
5. If the receive or input signal is not specified, use the most ap-
ECO SENSOR OFF
propriate signal for adjustment.
BLUE BACK OFF
6. Never touch parts (such as variable resistors, transformers and
capacitors) not shown in the adjustment items of this service
adjustment.
MEASURING INSTRUMENT ADJUSTMENT/CHECK ITEMS
AND FIXTURES Adjustment/Check item Page
1. DC voltmeter (or Digital voltmeter) B1 POWER SUPPLY Check 14
2. Oscilloscope
FOCUS Adjustment 14
3. Signal generator (Pattern generator)
[PAL / SECAM / NTSC] IF CIRCUIT Adjustment 14
4. Remote control unit
V/C (VIDEO/CHROMA) CIRCUIT Adjustment 15
DEFLECTION CIRCUIT Adjustment 20
VSM PRESET Adjustment 22
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:
q 1. IF .............................
For entering/adjusting the setting values (adjustment values) of the IF circuit.
q 2. V/C ...........................
For entering/adjusting the setting values (adjustment values) of the VIDEO/CHROMA circuit.
q 3. DEF .........................
For entering/adjusting the setting values (adjustment values) of the DEFLECTION circuit.
q 4. VSM PRESET ......... For setting the values of STANDARD, SOFT and BRIGHT. (Do not adjust the preset values.)
(VSM: video status memory)
q 5. PRESET .................. For setting the values for VIDEO/CHROMA control. (Do not adjust the preset values.)
q 6. TURBO TIMER ........ For quick setting the values of TIMER COUNT -- adjustable not only by minutes but also by second. If it i s ON,
the time in TIMER mode changes from 1 minute into 1 second temporarily. (Applicable to OFF TIMER, ON
TIMER and AUTO SHUTOFF)
Note: When you turn the TV power off, the Turbo Timer is automatically set to OFF.
10 No. 56028
AV-20N4
3. BASIC OPERATION IN SERVICE MENU SERVICE MENU
(1) How to enter SERVICE MENU
Press the DISPLAY key and the PICTURE MODE key on SERVICE MENU
the remote control unit simultaneously.
1. IF 2. V/C
The SERVICE MENU screen will be displayed. (See Fig. 1.) 3. DEF 4. VSM PRESET
5. PRESET
6. TURBO TIMER OFF
1-6 : SELECT DISP : EXIT
VVVVVVVV VVVVV VV.VVVV
VVV VVVVV VV.VVVV
Fig. 1
(2) Selection of SUB MENU SCREEN
Press one of the keys 1 ~ 6 on the remote control unit, and select the SUB MENU SCREEN from the SERVICE MENU. (See Fig. 2 on
the next page.)
SERVICE MENU SUB MENU 1. IF
2. V / C
3. DEF
4. VSM PRESET
5. PRESET
6. TURBO TIMER
(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) . ................................ Adjust VCO(CW) while watching the colour (yellow/blue) of the characters on the screen.
For details, refer to the adjustment table.
(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.
(c) MENU - / + Key ......................... Adjust the setting value.
(d) DISPLAY Key ............................ When this is pressed twice, you will return to the SERVICE MENU.
2) 2. V/C, 3. DEF, 4. VSM PRESET and 5. PRESET
Note: Do not adjust "4. VSM PRESET" and "5. PRESET" unless you had changed its value by mistake.
(a) 2 ~ 5 Keys ................................. Select one from 2. V/C, 3. DEF, 4. VSM PRESET and 5. PRESET.
(b) MENU a key ........................ Select setting items.
(c) MENU - / + Key ......................... Adjust the setting values of the setting items.
q Use the number keys on the remote control unit for setting of WHITE BALANCE and BLACK
OFFSET. For the setting, refer to each item concerned.
(d) DISPLAY Key ............................ When this is pressed, you will return to the SERVICE MENU.
3) 6. TURBO TIMER
(a) 6 Key ......................................... Each time you press the key, ON/OFF state of TURBO TIMER changes.
(Should be set to OFF.)
(4) Release of SERVICE MENU
After completing the setting, return to the SERVICE MENU by pressing the DISPLAY key, then again press the DISPLAY key to return
to the normal screen.
No. 56028 11
AV-20N4
SUB MENU SCREEN
SERVICE MENU SUB MENU 1. IF
SERVICE MENU
IF VCO (CW) VVV.VV MHz
1. IF 2. V/C TOO HIGH
3. DEF 4. VSM PRESET
1. VCO ABOVE REFERENCE
5. PRESET
2. DELAY POINT JUST REFERENCE
6. TURBO TIMER OFF
BELOW REFERENCE
TOO LOW
AFT ADJUST VVV
1-6 : SELECT DISP : EXIT
VCO ADJUST VVV
VVVVVVVV VVVVV VV.VVVV 1-2 : SELECT DISP : EXIT
FINE
VVV VVVVV VV.VVVV DISP : EXIT
DELAY POINT
AGC TAKE-OVER VV
- / + : OPERATE DISP : EXIT
SUB MENU 2. V/C
Setting item
V/C PAL
1. CUTOFF(R/G/B)
2. DRIVE(R/B)
1. CUTOFF (R) V VV 3. BRIGHT
(G) V VV 4. CONT.
(B) V VV 5. COLOUR (P / S/ N3 / N4)
6. TINT (N3 / N4)
50Hz 7. SECAM BL ADJ
8. SHARP (TV / VIDEO) Do not adjust.
a : SELECT
9. AMP. T SHARP
- / + : OPERATE DISP : EXIT
SUB MENU 5. PRESET SUB MENU 3. DEF
50Hz / 60Hz
PRESET PAL DEF. Setting item
1. VER. POSITION
1. C-TRAP FIX VVV 1. VER. POSITION VVV 2. HOR. POSITION
3. VER. HEIGHT
4. VER. LINEARITY
5. VER. SCURVE
50Hz B/G 50Hz 6. HOR. VCO ADJUST Do not adjust.
a : SELECT a : SELECT
- / + : OPERATE DISP : EXIT - / + : OPERATE DISP : EXIT
Do not adjust.
SUB MENU 4. VSM PRESET
BRIGHT / STD / SOFT
BRIGHT
6 . TURBO TIMER
TINT VVV
COLOUR VVV
TURBO TIMER OFF BRIGHT VVV
Do not adjust.
CONT. VVV
ON SHARP VVV
a : SELECT
- / + : OPERATE DISP : EXIT
Fig. 2
12 No. 56028
AV-20N4
ADJUSTMENT LOCATIONS
CRT SOCKET PWB (Within MAIN PWB)
(SOLDER SIDE)
TOP
U
TP-47R/G
TP-47G/R TP-47B
E1
TP-E
T
MAIN PWB
FRONT
F901
IC701 IC702
MEMORY IC
PW
DEG
S
IC301 S1 HV
TU001
5 1
U
HVT
1 Pin TP-91(B1) UPPER: FOCUS
2 Pin NC LOWER: SCREEN
3 Pin X-ray 1
4 Pin X-ray 2
5 Pin TP-E( )
No. 56028 13
AV-20N4
ADJUSTMENTS
B1 POWER SUPPLY
Measuring Description
Item Test point Adjustment part
instrument
Check of q Signal TP-91 (B1) 1. Receive a whole black signal.
B1 POWER Generator TP-E (")
" 2. Connect a DC voltmeter between TP-91 (B1) and TP-E (")
SUPPLY q DC [S1 (between pins 1 and 5 of the connector S1).
Voltmeter connector] 3. Make sure that the voltage is DC114.5 ± 1.5V.
FOCUS ADJUSTMENT
Measuring Description
Item Test point Adjustment part
instrument
Adjustment Signal FOCUS VR 1. Receive a cross-hatch signal.
of FOCUS generator [In HVT] 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.
IF CIRCUIT ADJUSTMENT
Measuring Description
Item Test point Adjustment part
instrument
Adjustment Remote VCO (CW) q Under normal conditions, no adjustment is required.
of VCO (CW) control unit Note: Do not adjust without inputting signal.
1. Receive a colour bar signal.
2. Select 1. IF from the SERVICE MENU.
3. Press the 1 key to select 1. VCO.
4. Select VCO ADJUST with the MENU a key and make sure
that the setup value shown in the screen is +00.
VCO (CW) VVV.VV MHz fv
5. Press the MENU - or + key until the colour of the characters
TOO HIGH
"TOO HIGH" displayed on the screen changes from blue to
ABOVE REFERENCE
JUST REFERENCE YELLOW yellow.
BELOW REFERENCE 6. Press the MENU - or + key until the colour of the characters
TOO LOW
AFT ADJUST VVV "TOO LOW" displayed on the screen changes from blue to
VCO ADJUST VVV yellow. At this time, check that the value of VCO ADJUST on
FINE Do not adjust.
DISP : EXIT the screen is +00 or about +00.
7. Select AFT ADJUST with the MENU a key.
8. Then, press the MENU - or + key until the colour of the char-
acters "JUST REFERENCE" displayed on the screen changes
from blue to yellow.
9. Press the DISPLAY key three times to return to normal screen.
14 No. 56028
AV-20N4
Measuring Description
Item Test point Adjustment part
instrument
Adjustment Remote DELAY POINT 1. Receive a black and white signal (colour off).
of DELAY control unit (AGC TAKE-OVER) 2. Select 1. IF from the SERVICE MENU.
POINT 3. Select 2. DELAY POINT by pressing the 2 key on the remote
control.
4. Adjust the MENU - or + key until video noise disappears.
Variable Initial setting 5. Press the DISPLAY key three times to return to the normal
Setting (Adjustment) Item
range value
screen.
DELAY POINT 6. Turn to other channels and make sure that there are no irregu-
0 ~ 127 43 larities.
(AGC TAKE-OVER)
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.
q Do not change the initial setting values of the setting (adjustment) items not listed in "ADJUSTMENT".
[SUB MENU 2. V/C]
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 -50 b b b
2. DRIVE (R / B) -64 ~ +63 0 b b b
3. BRIGHT -128 ~ +127 0 b b b
4. CONT. -64 ~ +63 0 b b b
5. COLOUR (P / S / N3 / N4) -64 ~ +63 0 b b b
6. TINT (N3 / N4) TV / VIDEO -64 ~ +63 0/0 0 / -2
7. SECAM BL ADJUST -32 ~ +31 0 b b b
8. SHARP TV / VIDEO -32 ~ +31 -7 / +15 b b b
9. AMP T. SHARP -16 ~ +15 -12 b b b
: Do not adjust.
No. 56028 15
AV-20N4
Measuring
Item Test point Adjustment part Description
instrument
Adjustment q Signal 1. CUTOFF (R) 1. Receive a black and white signal (colour off).
of WHITE generator CUTOFF (G) 2. Select 2. V/C from the SERVICE MENU.
BALANCE CUTOFF (B) 3. Select 1. CUTOFF (R), (G) and (B) with the MENU a key,
(Low light) q Remote and set each value to initial setting value with 4 ~ 9 keys on
control SCREEN VR the remote control unit.
unit (In HVT) 4. Press the 1 key on the remote control unit to produce a single
horizontal line.
5. Turn the SCREEN VR fully counterclockwise, then slowly turn
V/C PAL
it clockwise to where a red, blue, or green colour is faintly vis-
ible.
1. CUTOFF (R) V VV 6. Use keys 4 ~ 9 on the remote control unit and adjust the other
(G) V VV 2 colours to where the single horizontal line appears white.
(B) V VV
7. Turn the SCREEN VR to where the single horizontal line glows
50Hz faintly.
a : SELECT 8. Press the 2 key to return to 1. CUTOFF screen.
- / + : OPERATE DISP : EXIT 9. Press the DISPLAY key twice to return to the normal screen.
Setting (Adjustment) Variable Initial setting
item range value
R -128 ~ +127 -50
REMOTE CONTROL UNIT
H.LINE OFF 1. CUT OFF G -128 ~ +127 -50
1 2 3 B -128 ~ +127 -50
H.LINE ON
G. CUTOFF ( )
4 5 6
R. CUTOFF ( ) B. CUTOFF ( )
R. DRIVE ( ) B. DRIVE ( )
7 8 9
R. CUTOFF ( ) B. CUTOFF ( )
R. DRIVE ( ) B. DRIVE ( )
G. CUTOFF ( )
Adjustment q Signal 2. DRIVE (R) 1. Receive a black and white signal (colour off).
of WHITE generator DRIVE (B) 2. Select 2. V/C from the SERVICE MENU.
BALANCE 3. Select 2. DRIVE (R) / (B) with MENU a key, and set each
(High light) q Remote value to initial setting value with 4 and 7 keys, or 6 and 9 keys
control on the remote control unit.
unit 4. Use the keys 4 and 7 or 6 and 9 to produce a white screen.
5. Press the DISPLAY key twice to return to the normal screen.
Setting (Adjustment) Variable Initial setting
V/C PAL
item range value
2. DRIVE (R) V VV R -64 ~ +63 0
(B) V VV 2. DRIVE
B -64 ~ +63 0
50Hz
a : SELECT
- / + : OPERATE DISP : EXIT
16 No. 56028
AV-20N4
Measuring Description
Item Test point Adjustment part
instrument
Adjustment Remote 3. BRIGHT 1. Receive any broadcast.
of control unit 2. Select 2. V/C from the SERVICE MENU.
SUB 3. Select 3. BRIGHT with the MENU a key.
BRIGHT 4. Set the initial setting value with the MENU - or + key.
5. If the brightness is not the best with the initial set value, make
fine adjustment until you get the best brightness.
6. Press the DISPLAY key twice to return to the normal screen.
Adjustment Remote 4. CONT. 1. Receive any broadcast.
of control unit 2. Select 2. V/C from the SERVICE MENU.
SUB CONT. 3. Select 4. CONT. with the MENU a key.
4. Set the initial setting value with the MENU - or + key.
5. If the contrast is not the best with the initial set value, make
fine adjustment until you get the best contrast.
6. Press the DISPLAY key twice to return to the normal screen.
Adjustment Remote 5. COLOR [Method of adjustment without measuring instrument]
of