JVC AV-20N8(BK) User manual

AV-20N8
No. 56030 1
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
BASIC CHASSIS
CL-M
AV-20N8
COPYRIGHT  2000 VICTOR COMPANY OF JAPAN, LTD. No. 56030
Jul. 2000
+
+
−
−
SERVICE MANUAL
COLOUR TELEVISION
AV-20N8(BK)

AV-20N8
No. 560302
Item Content
Dimensions (W ×H ×D) 619mm ×458mm ×488mm
Mass 19kg
TV RF System B / G, I, D / K, K1, M
Colour System TV Mode PAL / SECAM / NTSC3.58 / NTSC4.43
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 ●Cable TVs of Mid (X-Z, S1-S10)
Super (S11-S20) & Hyper (S21-S41) bands receivable
Intermediate VIF Carrier 38.0MHz
Frequency SIF Carrier 31.5MHz (6.5MHz)
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 75ΩUnbalanced
Power Input Rating: AC110 ~ 240V, 50/60Hz Operating: AC90 ~ 260V, 50/60Hz
Power Consumption 110W (Max.) / 78W (Avg.)
Picture Tube Visible size : 48cm measured diagonally
High Voltage 26.5kV ±1kV (at zero beam current)
Speaker 5cm ×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-C219-1C (Battery size : AA/R06/UM-3 ×2)
Design & specifications are subject to change without notice.
SPECIFICATIONS

AV-20N8
No. 56030 3
SAFETY PRECAUTIONS
8. When service is required, observe the original lead dress. Ex-
tra 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 com-
ponents.
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 ter-
minals, 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 elec-
trical shock.
(1) Dielectric Strength Test
The isolation between theAC primary circuit and all metal parts
exposed to the user, particularly any exposed metal part hav-
ing 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 ex-
posed 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
0.5mAAC (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 volt-
meter having 1000 ohms per volt or more sensitivity in the fol-
lowing manner. Connect a 1500Ω10W resistor paralleled by a
0.15µF AC-type capacitor between an exposed metal part and
a known good earth ground (water pipe, etc.). Measure theAC
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 volt-
age measured must not exceed 0.75V AC (r.m.s.). This corre-
sponds to 0.5mAAC (r.m.s.).
However,in tropical area,this must not exceed 0.3VAC(r.m.s.).
This corresponds to 0.2mAAC (r.m.s.).
1. The design of this product contains special hardware, many
circuits and components specially for safety purposes. For con-
tinued protection, no changes should be made to the original
design unless authorized in writing by the manufacturer. Re-
placement 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 manufac-
turer of responsibility for personal injury or property damage
resulting therefrom.
3. Many electrical and mechanical parts in the products have spe-
cial safety-related characteristics. These characteristics are of-
ten not evident from visual inspection nor can the protection
afforded by them necessarily be obtained by using replace-
ment components rated for higher voltage, wattage, etc. Re-
placement parts which have these special safety characteris-
tics are identified in the parts list of Service manual. Electrical
components having such features are identified by shad-
ing on the schematics and by (!) on the parts list in Ser-
vice 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 re-
pairing.
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 ISO-
LATED (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 bro-
ken.
5. If any repair has been made to the chassis, it is recommended
that the B1 setting should be checked or adjusted (See AD-
JUSTMENT 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 com-
ponent damage, therefore operation under excessive high volt-
age conditions should be kept to a minimum, or should be pre-
vented. If severe arcing occurs, remove theAC power immedi-
ately and determine the cause by visual inspection (incorrect
installation, cracked or melted high voltage harness, poor sol-
dering, etc.). To maintain the proper minimum level of soft X-
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-
age meter or a high voltage probe with a VTVM. Discharge the
picture tube before attempting meter connection, by connect-
ing a clip lead to the ground frame and connecting the other
end of the lead through a 10kΩ2W resistor to the anode but-
ton.
AC VOLTMETER
(HAVING 1000Ω/V,
OR MORE SENSITIVITY)
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART
1500Ω10W
0.15µF AC-TYPE
GOOD EARTH GROUND

AV-20N8
No. 560304
SPECIFIC SERVICE INSTRUCTIONS
DISASSEMBLY PROCEDURE
REMOVING THE REAR COVER
1. Unplug the AC power cord.
2. Remove the 6screws marked "A" and 2screws 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 2screws 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:
●When erecting the Main PW Board, be careful so that there will
be no contacting with other PW Board.
●Beforeturning onpower,make sure thatall connectorsare 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.
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.
●I2C bus control utilizes single chip ICs for IF, V/C (Video/Chroma) and VSM (Video Status Memory).
●By means ofAUTO PROGRAM, the TV stations can be selected automatically and theTV 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 +.

AV-20N8
No. 56030 5
(×6)
(×2)
(×2)
(×2)
A
B
C
C
CRT SOCKET PWB
(Within MAIN PWB)
MAIN PWB
SPEAKER
SPEAKER
REAR COVER
A2 PWB
FRONT CABINET

AV-20N8
No. 560306
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, re-
fer 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 SYS-
TEM CONSTANT SET screen will be displayed. (See
Fig. 2.)
3) Check whether thesettingvalues of theSYSTEM CON-
STANT SET are the same as those indicated in Table
1. If the value is different, select the setting item with
the MENU akey, 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, per-
form adjustment referring to "SERVICEADJUSTMENTS".
Fig. 1
SERVICE MENU
1. IF
3. VSM PRESET 2.V/C
SERVICE MENU
1-3 : SELECT DISP : EXIT
✽✽✽✽✽✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
SYSTEM CONSTANT - I
SYSTEM CONSTANT SET 1/3
SYSTEM CONSTANT - II
SYSTEM CONSTANT SET 2/3
−/+: OPERATE DISP : EXIT
− / + : OPERATE DISP : EXIT
1. LANGUAGE : E/T
12. TUNER : MA
13. AMP TUNER : YES
14. VNR : NO
SYSTEM CONSTANT - III
SYSTEM CONSTANT SET 3/3
− / + : OPERATE DISP : EXIT
Fig. 2
a: SELECT
a: SELECT
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

AV-20N8
No. 56030 7
DISPLAY POWER
MENU
+
+
−
−
LIVE
SPATIAL
CHANNEL VOLUME
SYSTEM
COLOUR SOUND MUTING
PICTURE MODE
RETURN+
ECO SENSOR OFF TIMER
123
456
78
0
9
-/--
RM-C234 REMOTE CONTROL UNIT
MENU
MENU
MENU
+
PICTURE
MODE
DISPLAY
MENU
−
TV/VIDEO
CHANNEL SCAN
I/II
PICTURE
BOOSTER
NAME OF REMOTE CONTROL KEYS
Setting item Setting value Setting item Setting value
SUB POWER ON TREBLE CENTER
CHANNEL POSITION 1 POSITION BASS CENTER
CHANNEL PRESET Refer to OPERATING INSTRUCTION. BALANCE CENTER
VOLUME Appropriate sound volume OFF TIMER OFF
TV/VIDEO TV AUTO SHUTOFF OFF
ON SCREEN DISPLAY POSITION NUMBER DISPLAY ECO SENSOR OFF
COLOUR SYSTEM PAL LANGUAGE THAI
SOUND SYSTEM B / G BLUE BACK OFF
BILINGUAL MODE ION TIMER PR1 0:00
PICTURE MODE (VSM) BRIGHT CHILD LOCK OFF
LIVE SPATIAL OFF PICTURE BOOSTER OFF
USER SETTING VALUES
Table 2
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/T
12. TUNER MA
13. AMP TUNER YES
14. VNR NO
SETTING OF SYSTEM CONSTANT SET Table 1
29 25 21 14
MULTI. TRIPLE PAL
13
YES NO
YES NO
YES NO
YES NO
YES NO
YES NO
YES NO
E E/T
MU MA
YES NO
YES NO

AV-20N8
No. 560308
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
SERVICE MENU SETTING ITEMS
Table 3
Service menu Setting item
3. VSM PRESET TINT
(BRIGHT/STD/SOFT) COLOUR
BRIGHT
CONT.
SHARP
Do not adjust.
Do not adjust.

AV-20N8
No. 56030 9
■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.
(2) Shift the chip part with tweezers and remove it.
●Transistors, diodes, variable resistors, etc.
(1) Apply extra solder to each lead.
(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.
Note : After removing the part, remove remaining solder from
the pattern.
REPLACEMENT OF CHIP COMPONENT
2. How to install Chip parts
●Resistors, capacitors, 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.
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 Aas indicated in the figure.
(4) Then solder leads Band C.
SOLDER SOLDER
A
B
C
A
B
C

AV-20N8
No. 5603010
SERVICE ADJUSTMENTS
BEFORE STARTING SERVICE ADJUSTMENT
MEASURING INSTRUMENT
AND FIXTURES
1. DC voltmeter (or Digital voltmeter)
2. Oscilloscope
3. Signal generator (Pattern generator)
[PAL / SECAM / NTSC]
4. Remote control unit
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 con-
dition can be different from the initial setting values.
3. Make sure thatconnectionis correctly madetoAC power source.
4. Turnonthe power oftheTV and measuringinstrument for warm-
ing up for at least 30 minutes before starting adjustment.
5. If the receive or input signal is not specified, use the most ap-
propriate 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.
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-
cuits.
●3. VSM PRESET ......... For setting the values of STANDARD, SOFT and BRIGHT
(VSM: video status memory)
ADJUSTMENT/CHECK ITEMS
Adjustment/Check item Page
B1 POWER SUPPLY Check 14
FOCUS Adjustment 14
IF CIRCUITAdjustment 14
V/C (VIDEO/CHROMA) CIRCUITAdjustment 15
DEFLECTION CIRCUIT Adjustment 21
VSM PRESET Adjustment 23
A2 SIF/DETAdjustment 23
PURITY, CONVERGENCE Adjustment 24
Function
PICTURE MODE (VSM)
COLOUR/BRIGHT/CONT./SHARP
OFF TIMER
ECO SENSOR
BLUE BACK
PICTURE BOOSTER
Setting value
BRIGHT
See "VSM Preset"
on page 23.
OFF
OFF
OFF
OFF

AV-20N8
No. 56030 11
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
Fig. 1
SERVICE MENU
1. IF
3. VSM PRESET 2.V/C
SERVICE MENU
1-3 : SELECT DISP : EXIT
✽✽✽✽✽✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
SUB MENU SCREEN
Fig. 2
SERVICE MENU
BRIGHT
✽✽
✽✽
✽✽
✽✽
✽✽
SUB MENU 3.VSM PRESET
a: SELECT
− / + : OPERATE DISP : EXIT
BRIGHT / STD / SOFT
Setting item
TINT
COLOUR
BRIGHT
CONT.
SHARP
1.VCO
2. DELAY POINT
1-2 : SELECT DISP : EXIT
IF
SUB MENU 1. IF
VCO (CW) ✽✽✽.✽✽ MHz
TOO HIGH
ABOVE REFERENCE
BELOW REFERENCE
TOO LOW
DISP : EXIT
DELAY POINT
AGCTAKE-OVER
✽✽
−/+: OPERATE DISP : EXIT
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.
10. H. CENTER
11. V. HEIGHT
12. V. LIN
13. V.S-CR
14. V. CENTER
15. AMP T. SHARP
Setting item
PAL
1. CUTOFF (R)
✽ ✽✽
(G) ✽ ✽✽
− / + : OPERATE DISP : EXIT
(B)
✽ ✽✽
a: SELECT
V/C
SUB MENU 2.V/C
1. IF
3. VSM PRESET 2.V/C
SERVICE MENU
1-3 : SELECT DISP : EXIT
✽✽✽✽✽✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
✽✽✽ ✽✽✽✽✽ ✽✽.✽✽✽✽
50Hz
TINT
COLOUR
BRIGHT
CONT.
SHARP

AV-20N8
No. 5603012
(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.
(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 and 3. VSM PRESET
(a) 2 and 3 Keys ............................. Select 2. V/C and 3. VSM PRESET.
(b) MENU akey........................ Select setting items.
(c) MENU −/ +Key......................... Adjust the setting values of the setting items.
●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.
(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.

AV-20N8
No. 56030 13
ADJUSTMENT LOCATIONS
S
VCO S1
HV
U
MEMORY
IC
IC702
IC701
-MENU +
F901
PW
TU001
POWER SW
S901
DEG
T101
HVT
UPPER : FOCUS
LOWER : SCREEN
REMOCON
RECEIVER
POWER
ON
TIMER ECO
SENSOR VOL -+CH
T
FRONT
MAIN PWB
1 Pin TP-91(B1)
2 Pin NC
3 Pin X-ray1
4 Pin X-ray2
5 Pin TP-E
(")
15
TOP
CRT SOCKET PWB
(SOLDER SIDE)
TP-E
E1
TP-47G
T
U
CRT EARTH
(BRAIDED ASS'Y)
A2 PWB
CN001
IC201
CN001
T601
TOP
1
56
29
28
SIF/DET
IC601
IC602

AV-20N8
No. 5603014
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.
Measuring
Item Test point Adjustment part
instrument
Adjustment Remote VCO (CW)
of VCO (CW) control unit TRANSF.
[MAIN PWB]
Description
●Under normal conditions, no adjustment is required.
1. Select 1. IF from the SERVICE MENU.
2. Press the 1key to select 1. VCO.
3. Select a receivable broadcast channel with the CHANNELkey.
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. counterclock-
wiseuntil thecharacters "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.
ADJUSTMENTS
B1 POWER SUPPLY
Measuring
Item Test point Adjustment part
instrument
Check of Signal TP-91 (B1)
B1 POWER Generator TP-E (""
""
")
SUPPLY [S1
DC Voltmeter connector]
Measuring
Item Test point Adjustment part
instrument
Adjustment Signal FOCUS VR
of FOCUS generator [In HVT]
FOCUS ADJUSTMENT
IF CIRCUIT ADJUSTMENT
Step
Screen display 123
TOO HIGH Yellow Blue Blue
ABOVE REFERENCE Blue Yellow Blue
BELOW REFERENCE Blue Blue Yellow
TOO LOW Blue Blue
TOO HIGH
ABOVE REFERENCE
BELOW REFERENCE
TOO LOW
VCO (CW) ✽✽✽.✽✽ MHz
DISP : EXIT
fv
YELLOW

AV-20N8
No. 56030 15
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 +5 / +3b b b
9. TEXT (RGB) CONT. −128 ~ +127 +15 b b b
15. AMP T. SHARP −128 ~ +127 −15 b b b
Measuring
Item Test point Adjustment part
instrument
Adjustment Remote DELAY POINT
of DELAY control unit (AGC TAKE-OVER)
POINT
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 2key 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 irregu-
larities.
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 T. SHARP)]
Setting Variable Initial setting
(Adjustment) range value
item
DELAY POINT 0 ~63 20
(AGC TAKE-OVER)
: Do not adjust.

AV-20N8
No. 5603016
Measuring
Item Test point Adjustment part
instrument
Adjustment ●Signal 1. CUTOFF (R)
of WHITE generator CUTOFF (G)
BALANCE CUTOFF (B)
(Low light) ●Remote
control SCREEN VR
unit (In HVT)
Adjustment ●Signal 2. DRIVE (R)
of WHITE generator DRIVE (B)
BALANCE
(High light) ●Remote
control
unit
Description
1. Receive a black and white signal (colour off).
2. Select 2. V/C from the SERVICE MENU.
3. Select 1. CUTOFF (R), (G) and (B) with MENU akey, and
set each value to initial setting value with 4~9keys on the
remote control unit.
4. Press the 1key on the remote control unit to produce a single
horizontal line.
5. Turn the SCREEN VR fully counterclockwise, then slowly turn
it clockwise to where a red, blue, or green colour is faintly vis-
ible.
6. Use keys 4~9on the remote control unit and adjust the other
2 colours to where the single horizontal line appears white.
7. Turn the SCREEN VR to where the single horizontal line glows
faintly.
8. Press the 2key to return to 1. CUTOFF screen.
9. Press the DISPLAY key twice to return to the normal screen.
1. Receive a black and white signal (colour off).
2. Select 2. V/C from the SERVICE MENU.
3. Select 2. DRIVE (R) / (B) with MENU akey, and set each
value to initial setting value with 4and 7keys, or 6and 9keys
on the remote control unit.
4. Use the keys 4and 7or 6and 9to produce a white screen.
5. Press the DISPLAY key twice to return to the normal screen.
Setting (Adjustment) Variable Initial setting
item range value
R−128 ~+127 0
2. DRIVE B−128 ~+127 0
Setting (Adjustment) Variable Initial setting
item range value
R−128 ~+127 0
1. CUT OFF G −128 ~+127 0
B−128 ~+127 0
PAL
2. DRIVE (R)
✽ ✽✽
(B) ✽ ✽✽
− / + : OPERATE DISP : EXIT
a: SELECT
V/C
50Hz
PAL
1. CUTOFF (R)
✽ ✽✽
(G) ✽ ✽✽
− / + : OPERATE DISP : EXIT
(B)
✽ ✽✽
a: SELECT
V/C
50Hz
R. CUTOFF ( )
G. CUTOFF ( )
H.LINE OFF
H.LINE ON
12 3
4
789
56
R. CUTOFF ( )
R. DRIVE ( )
R. DRIVE ( )
G. CUTOFF ( )
B. CUTOFF ( )
B. DRIVE ( )
B. CUTOFF ( )
B. DRIVE ( )
REMOTE CONTROL UNIT

AV-20N8
No. 56030 17
Measuring
Item Test point Adjustment part
instrument
Adjustment Remote 3. BRIGHT
of control unit
SUB
BRIGHT
Adjustment Remote 4. CONT.
of control unit
SUB CONT.
Adjustment Remote 5. COLOR
of control unit
SUB
COLOUR-IPAL COLOUR
SECAM COLOUR
NTSC 3.58 COLOUR
Description
1. Receive any broadcast.
2. Select 2. V/C from the SERVICE MENU.
3. Select 3. BRIGHT with the MENU akey.
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.
1. Receive any broadcast.
2. Select 2. V/C from the SERVICE MENU.
3. Select 4. CONT. with the MENU akey.
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.
[Method of adjustment without measuring instrument]
(PAL COLOUR)
1. Receive a PAL broadcast.
2. Select 2. V/C from the SERVICE MENU.
3. Select 5. COLOUR with the MENU akey.
4. Set the initial setting value for PAL COLOUR with the MENU
−or +key.
5. If the colour is not the best with the initial set value, make fine
adjustment until you get the best colour.
6. Press the DISPLAY key twice to return to the normal screen.
(SECAM COLOUR)
1. Receive a SECAM broadcast.
2. Make fine adjustment of SECAM COLOUR in the same way
as for "PAL COLOUR".
(NTSC 3.58 COLOUR)
1. Receive a NTSC 3.58MHz broadcast.
2. Make similar fine adjustment of NTSC 3.58 COLOUR in the
same way as for "PAL COLOUR".
(NTSC 4.43 COLOUR)
When adjustment is done for NTSC 3.58 COLOUR, appropriate
values are automatically set for NTSC 4.43 COLOUR.

AV-20N8
No. 5603018
Measuring
Item Test point Adjustment part
instrument
Adjustment ●Signal TP-47G 5. COLOUR
of SUB generator TP-E (""
""
")
COLOUR-II [CRT
●Oscillo- SOCKET PAL COLOUR
scope PWB]
●Remote
control
unit
SECAM COLOUR
NTSC 3.58 COLOUR
Description
[Method of adjustment using measuring instrument]
(PAL COLOUR)
1. Receive a PAL full field colour bar signal (75% white).
2. Select 2. V/C from the SERVICE MENU.
3. Select 5. COLOUR with the MENU akey.
4. Set the initial setting value of PAL COLOUR with the MENU
−or +key.
5. Connect the oscilloscope between TP-47G and TP-E.
6. Adjust PAL COLOUR to set the value (A) in the figure to +7V
(W & G).
(SECAM COLOUR)
1. Receive a SECAM full field colour bar signal (75% white).
2. Set the initialsetting value ofSECAMCOLOUR with theMENU
−or +key.
3. Adjust SECAM COLOUR to set the value (A) in the figure to
+7V (W & G).
(NTSC 3.58 COLOUR)
1. Receive a NTSC 3.58 full field colour bar signal (75% white).
2. Set the initial setting value of NTSC 3.58 COLOUR with the
MENU −or +key.
3. Adjust NTSC 3.58 COLOUR to set the value (A) in the figure
to +6V (W & G).
(NTSC 4.43 COLOUR)
When adjustment is done for NTSC 3.58 COLOUR, appropriate
values are automatically set for NTSC 4.43 COLOUR.
Mg B
(−)
0V
(+)
R
Cy
Y
WG
(A)

AV-20N8
No. 56030 19
Measuring
Item Test point Adjustment part
instrument
Adjustment Remote 6. TINT
of control unit
SUB TINT-INTSC 3.58 TINT
Adjustment ●Signal TP-47G 6. TINT
of generator TP-E (""
""
")
SUB TINT-II [CRT
●Oscillo- SOCKET
scope PWB] NTSC 3.58 TINT
●Remote
control
unit
Description
[Method of adjustment without measuring instrument]
(NTSC 3.58 TINT)
1. Receive a NTSC 3.58 colour bar signal (full field colour bar
75% white).
2. Select 2. V/C from the SERVICE MENU.
3. Select 6. TINT with the MENU akey.
4. Set the initial setting value of NTSC 3.58 with the MENU −or
+key.
5. If you cannot get the best tint with the initial setting value,
make fine adjustment until you get the best tint.
6. Press the DISPLAY key twice to return to the normal screen.
(NTSC 4.43 COLOUR)
When adjustment is done for NTSC 3.58 TINT, appropriate val-
ues are automatically set for NTSC 4.43 TINT.
[Method of adjustment using measuring instrument]
(NTSC 3.58 TINT)
1. Receive a NTSC 3.58 colour bar signal (full field colour bar
75% white).
2. Select 2. V/C from the SERVICE MENU.
3. Select 6. TINT with the MENU akey.
4. Set the initial setting value of NTSC 3.58 with the MENU −or
+key.
5. Connect the oscilloscope between TP-47G and TP-E.
6. Adjust NTSC 3.58 TINT to set the value (B) in the figure to
+6V (W & Cy).
7. Press the DISPLAY key twice to return to the normal screen.
(NTSC 4.43 TINT)
When adjustment is done for NTSC 3.58 TINT, appropriate val-
ues are automatically set for NTSC 4.43 TINT.
Mg B
(−)
0V
(+)
R
Cy
Y
W
(B)
G

AV-20N8
No. 5603020
Measuring
Item Test point Adjustment part
instrument
Adjustment Remote
of BLACK control unit
OFFSET-I
(SECAM) 7.BLACK OFFSET
(R-Y)
(B-Y)
Adjustment ●Signal 35 PIN (R-Y)
of BLACK generator 36 PIN (B-Y)
OFFSET-II IC 201 on
(SECAM) ●Oscillo- MAIN PWB 7.BLACK OFFSET
scope (R-Y)
(B-Y)
●Remote
control
unit
Description
[Method of adjustment without measuring instrument]
1. Receive a SECAM broadcast.
2. Select 2. V/C from the SERVICE MENU.
3. Select 7. BLACK OFFSET with the MENU akey.
4. Set the initial setting value for BLACK OFFSET (R-Y) and (B-
Y) with 4and 7or 6and 9keys on the remote control unit.
5. If the picture is not the best with the initial setting value, make
fine adjustment until you get the best picture.
6. Press the DISPLAY key twice to return to the normal screen.
[Method of adjustment using measuring instrument]
1. Receive a SECAM COLOUR bar signal (full field colour bar
75% white).
2. Select 2. V/C from the SERVICE MENU.
3. Select 7. BLACK OFFSET with the akey.
4. Connect the oscilloscope between pin 35 of IC 201 and TP-E.
5. By using 4and 7keys on the remote control unit, adjust the
BLACK OFFSET (R-Y) so that the waveform changes from
(a) to (b) as shown in the figure.
6. Connect the oscilloscope between pin 36 of IC 201 and TP-E.
7. By using 6and 9keys on the remote control unit, adjust the
BLACK OFFSET (B-Y) so that the waveform changes from
(c) to (d) as shown in the figure.
8. If the picture is not the best with the adjusted picture, make
fine adjustment until you get the best picture.
9. Press the DISPLAY key twice to return to the normal screen.
12 3
4
789
56
R-Y ( )
R-Y ( )
B-Y ( )
B-Y ( )
REMOTE CONTROL UNIT
BLACK &
WHITE ON
BLACK &
WHITE OFF
Flat Flat
(b)(a)
[R-Y]
(c) (d)
[B-Y] Flat Flat