Toshiba 20A3VX User manual

SERVICE MANUAL
COLOUR TELEVISION
Dec., 2003
FILE NO. 040-200117
S1E Chassis
20A3VX

– 2 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
TABLE OF CONTENTS
CHAPTER 1 GENERAL ADJUSTMENTS
SAFETY INSTRUCTIONS ........................................................................................................................................ 3
SET-UP ADJUSTMENT ............................................................................................................................................ 4
SERVICE MODE ...................................................................................................................................................... 6
DESIGN MODE ........................................................................................................................................................ 9
ELECTRICAL ADJUSTMENTS .............................................................................................................................. 10
CIRCUIT CHECK .................................................................................................................................................... 15
CHAPTER 2 SPECIFIC INFORMATIONS
SETTING & ADJUSTING DATA .............................................................................................................................. 16
LOCATION OF CONTROLS ................................................................................................................................... 17
PROGRAMMING CHANNEL MEMORY................................................................................................................. 18
CHASSIS AND CABINET REPLACEMENT PARTS LIST ......................................................................................20
PC BOARDS BOTTOM VIEW................................................................................................................................. 27
TERMINAL VIEW OF TRANSISTORS ................................................................................................................... 30
CIRCUIT BLOCK DIAGRAM .................................................................................................................................. 32
SPECIFICATIONS ............................................................................................................................................... End
APPENDIX:
CIRCUIT DIAGRAM

–3 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
CHAPTER 1 GENERAL ADJUSTMENTS
SAFETY INSTRUCTIONS
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU-
TION”AND “PRODUCT SAFETY NOTICE”INSTRUCTIONS BELOW.
X-RAY RADIATION PRECAUTION
1. Excessive high voltage can produce potentially hazard-
ous X-RAY RADIATION. To avoid such hazards, the high
voltage must not be above the specified limit. The nominal
value of the high voltage of this receiver is (A) kV at zero
beam current (minimum brightness) under a (C) V AC power
source. The high voltage must not, under any circum-
stances, exceed (B) kV.
Refer to table-1 for high voltage (A), (B) & AC voltage (C).
(See SETTING & ADJUSTING DATA on page 16)
Each time a receiver requires servicing, the high voltage
should be checked following the HIGH VOLTAGE CHECK
procedure in this manual. It is recommended that the read-
ing of the high voltage be recorded as a part of the service
record. It is important to use an accurate and reliable high
voltage meter.
2. The only source of X-RAY RADIATION in this TV receiver
is the picture tube. For continued X-RAY RADIATION pro-
tection, the replacement tube must be exactly the same
type tube as specified in the parts list.
3. Some part in this receiver have special safety-related char-
acteristics for X-RAY RADIATION protection. For contin-
ued safety, parts replacement should be undertaken only
after referring to the PRODUCT SAFETY NOTICE below.
SAFETY PRECAUTION
WARNING : Service should not be attempted by anyone unfamiliar with the necessary precautions on this receiver. The following
are the necessary precautions to be observed before servicing this chassis.
1. An isolation transformer should be connected in the power line between the receiver and the AC line before any service is
performed on the receiver.
2. Always discharge the picture tube anode to the CRT conductive coating before handling the picture tube. The picture tube
is highly evacuated and if broken, glass fragments will be violently expelled. Use shatter proof goggles and keep picture tube
away from the unprotected body while handling.
3. When replacing a chassis in the cabinet, always be certain that all the protective devices are put back in place, such as; non-
metallic control knobs, insulating covers, shields, isolation resistor-capacitor network etc.
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These characteristics are
often passed unnoticed by a visual inspection and the protection afforded by them cannot necessarily be obtained by using
replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety char-
acteristics are identified in this manual and its supplements; electrical components having such features are identified by
the international hazard symbols on the schematic diagram and the parts list.
Before replacing any of these components, read the parts list in this manual carefully. The use of substitute replacement
parts which do not have the same safety characteristics as specified in the parts list may create shock, fire, X-ray
radiation or other hazards.

–4 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU-
TION”AND “PRODUCT SAFETY NOTICE”ON PAGE 3 OF THIS MANUAL.
SET-UP ADJUSTMENT
■The following adjustments should be made when a complete realignment is required or a new picture tube is installed.
Perform the adjustments in order as follows :
1. Colour Purity
2. Convergence
3. White Balance
Note: The PURITY/CONVERGENCE MAGNET assembly and rubber wedges need mechanical positioning.
Refer to figure 1.
Mounting position of the purity magnet assembly should fit to same position as old one because slightly difference to
the position depend on a kind of tube.
*There are no adjustment of purity and convergence in some picture tube (Unified with purity magnet)
GLASS CLOTH
TAPES
DEFLECTION
YOKE
TEMPORARY
MOUNTING
RUBBER WEDGE
ADHESIVE
DEFLECTION
YOKE
PURITY/
CONVERGENCE
MAGNET ASS'Y
29.1mm(28", 29")
25mm(25")
19mm(19", 20", 21")
14mm(13", 14")
Figure 1.
COLOUR PURITY ADJUSTMENT
NOTE : Before attempting any purity adjustments, the receiver
should be operated for at least fifteen minutes.
1. Demagnetize the picture tube and cabinet using a degauss-
ing coil.
2. Set the brightness and contrast to maximum.
3. Use a green raster from among the built-in test signals.
4. Loosen the clamp screw holding the yoke and slide the
yoke backward or forward to provide vertical green belt
(zone) in the picture screen.
5. Remove the Rubber Wedges.
6. Rotate and spread the tabs of the purity magnet (See fig-
ure 2.) around the neck of the picture tube until the green
belt is in the center of the screen. At the same time, enter
the raster vertically.
7. Slowly move the yoke forward or backward until a uniform
green screen is obtained. Tighten the clamp screw of the
yoke temporarily.
8. Check the purity of the red and blue raster.

–5 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
CONVERGENCE ADJUSTMENTS
NOTE: Before attempting any convergence adjustments, the
receiver should be operated for at least fifteen min-
utes.
■CENTER CONVERGENCE ADJUSTMENT
1. Use the cross-dot pattern from among the built-in test sig-
nals.
2. Set the brightness and contrast for well defined pattern.
3. Adjust two tabs of the 4-Pole Magnets to change the an-
gle between them (See figure 2.) and superimpose red
and blue vertical lines in the center area of the picture
screen.
4. Turn the both tabs at the same time keeping the angle
constant to superimpose red and blue horizontal lines at
the center of the screen.
5. Adjust two tabs of 6-Pole Magnets to superimpose red/
blue line and green one. Adjusting the angle affects the
vertical lines and rotating both magnets affects the hori-
zontal lines.
6. Repeat adjustments 3, 4, 5 keeping in mind red, green
and blue movement, because 4-Pole Magnets and 6-Pole
Magnets have mutual interaction and make dot movement
complex.
■CIRCUMFERENCE CONVERGENCE ADJUSTMENT
1. Loosen the clamping screw of deflection yoke slightly to
allow the yoke to tilt.
2. Temporarily put a wedge as shown in figure 1. (Do not
remove cover paper on adhesive part of the wedge.)
3. Tilt front of the deflection yoke up or down to obtain better
convergence in circumference. (See figure 3.) Push the
mounted wedge into the space between picture tube and
the yoke to fix the yoke temporarily.
4. Put other wedge into bottom space and remove the cover
paper to stick.
5. Tilt front of the yoke right or left to obtain better conver-
gence in circumference. (See figure 3.)
6. Keep the yoke position and put another wedge in either
upper space. Remove cover paper and stick the wedge
on picture tube to fix the yoke.
7. Detach the temporarily mounted wedge and put it in an-
other upper space. Stick it on picture tube to fix the yoke.
8. After fixing three wedges, recheck overall convergence.
Tighten the screw firmly to fix the yoke and check the yoke
is firm.
9. Stick three adhesive tapes on wedges as shown in figure
1.
Figure 2.
BLU RED
BLU
RED
RED/BLU GRN
RED/BLU
GRN
B
G
R
R
G
B
BGR
RGB
BGR
RGB
R
G
B
B
G
R
4-POLE MAGNETS MOVEMENT
INCLINE THE YOKE UP (OR DOWN)
6-POLE MAGNETS MOVEMENT
Center Convergence by Convergence Magnets
Circumference Convergence by DEF Yoke
INCLINE THE YOKE RIGHT (OR LEFT)
Figure 3. Dot Movement Pattern
4-POLE
MAGNETS
PURITY
MAGNETS
6-POLE
MAGNETS
ADJUST THE ANGLE
(VERTICAL LINES) FIXED
ROTATE TWO TABS
AT THE SAME TIME
(HORIZONTAL LINES)
CONVERGENCE MAGNET ASSEMBLY ADJUSTMENT OF MAGNETS

–6 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
SERVICE MODE
1. ENTERING TO SERVICE MODE
S
(Service mode display)
Item
Data
3) While pressing the obutton,
press MENU button on TV set.
2) Press obutton again to
keep pressing.
2. DISPLAYING THE ADJUSTMENT MENU
1) Press MENU button on TV.
3. KEY FUNCTION IN THE SERVICE MODE
The following key entry during display of adjustment menu provides special functions.
A single horizontal line ON/OFF: - / - - button (on Remote) or abutton (on TV)
Test signal selection : abutton (on Remote)
Selection of the adjustment items : Channel s/t(on TV or Remote)
Change of the data value : Volume ;+/–(on TV or Remote)
Adjustment menu mode ON/OFF : MENU button (on TV)
Initialization of the memory (QA02) : CALL + Channel button on TV (s)
Reset the count of operating protect
circuit to “00”: CALL + Channel button on TV (t)
“RCUT”selection : 1 button
“GCUT”selection : 2 button
“BCUT”selection : 3 button
“CNTX”(or “SCNT”) selection : 4 button
“COLC”selection : 5 button
“TNTC”selection : 6 button
Test audio signal ON/OFF (1kHz) : 8 button
Self diagnostic display ON/OFF : 9 button
1) Press obutton once on
Remote Control.
Adjustment mode
Press
Press
Service mode
Item
Data
S
Color thickness correction
note: Displayed differently as shown below, de-
pending on the setting of the receiving color
system.
COLP (PAL)
COLC (NTSC)
COLS (SECAM)
CAUTION : Never try to perform initialization unless you have changed the memory IC.

–7 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
4. SELECTING THE ADJUSTING ITEMS
1) Every pressing of CHANNEL sbutton in the service mode changes the adjustment items in the order of table-2.
(tbutton for reverse order)
Refer to table-2 for preset data of adjustment mode.
(See SETTING & ADJUSTING DATA on page 16)
5. ADJUSTING THE DATA
1) Pressing of VOLUME ;+/–button will change the value of data in the range from 00H to FFH. The variable
range depends on the adjusting item.
6. EXIT FROM SERVICE MODE
1) Pressing POWER button to turn off the TV once.
■INITIALIZATION OF MEMORY DATA OF QA02
After replacing QA02, the following initialization is required.
1. Enter the service mode, then select any register item.
2. Press and hold the CALL button on the Remote, then press the CHANNEL sbutton on the TV. The initialization of QA02 has
been complated.
3. Check the picture carefully. If necessary, adjust any adjustment item above.
Perform “Auto search Memory”on the owner’s manual.
CAUTION: Never attempt to initialize the data unless QA02 has been replaced.
7. TEST SIGNAL SELECTION
1) Every pressing of abutton on the Remote Control changes the built-in test patterns on screen as described below
in SERVICE MODE.
Signals Picture
•Red raster
•Green raster
•Blue raster
•All Black
•All White
•Black & White
•Black cross-hatch
•White cross-hatch
•Black cross-dot
•White cross-dot
•Black cross-bar
•White cross-bar
•Black cross-bar
on green raster
•H signal (white)
•H signal (black)
* The signals marked with are not usable to display in the Test signal for some model.
Signal off NTSC signals (14 patterns)
PAL signals (14 patterns)

–8 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
8. SELF DIAGNOSTIC FUNCTION
1) Press “9”button on Remote Control during display of adjustment menu in the service mode.
The diagnosis will begin to check if interface among IC’s are executed properly.
2) During diagnosis, the following displays are shown.
23******
POWER : 00
BUS LINE : OK
BUS CONT : OK
BLOCK : UV V1 V2
QV01
<SELF CHECK>
Part number of microcomputer (QA01)
Operation number of protecting circuit ----“00”is nor-
mal.
When indication is other than “00”, overcurrent apts to
flow, and circuit parts may possibly be damaged.
BUS LINE CHECK ----“OK”is normal.
“SDA1-GND”------------- SDA-GND short circuit.
“SCL1-GND”-------------- SCL-GND short circuit.
“SCL1-SDA1”------------- SCL-SDA short circuit.
BUS CONT ----“OK”is normal.
When indication shows “Q uuu NG”, the device with
the number may possibly be damaged.
BLOCK
UV : TV reception mode
V1 : VIDEO 1 input mode (a1)
V2 : VIDEO 2 input mode (a2)
Indicated colour of mode now selected : Green and Red
Indicated colour of other modes : White
Green : Normal
Red : The microcomputer operates to provide judgement
of no video signal. The red colour is still indicated
though the signal is input, failure may exist in input
signal line including QV01.
QV01 : In case of indication green ---Normal
In case of indication red with input signal----
Failure may exist in output line including QV01.
NOTE: Component which controls character display on
screen is QT01 (TELETEXT IC.). If this display
function fails to operate due to damage in QT01,
self diagnosis procedure is as follows.
(1) In case that power indicator is blinking with
interval of 0.5 seconds; it means protecting cir-
cuit (Current limiter) is operating, and circuit
components may possibly be damaged. Check
related components.
(2) In case that power indicator is blinking with
interval of 1 second; Protecting circuit does
not operate, but a part of Bus line does not
operate normally. Check Bus line.





* The items marked with are not usable to display in the SELF DIAGNOSTIC FUNCTION for some model.

–9 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
DESIGN MODE
1. ENTERING TO DESIGN MODE
ITEM
DATA
S D Press
(Design mode) (Adjustment mode)
Press
3) Press MENU button on TV.
2) While pressing o(or CALL) button on
Remote and press MENU button on TV.
1) Select the Service mode.
2. SELECTING THE ADJUSTING ITEMS
Every pressing of CHANNEL tbutton in the design mode changes the adjustment items in the order of table-3.
(sbutton for reverse order)
Refer to table-3 for data of design mode.
(See SETTING & ADJUSTING DATA on page 16)
3. ADJUSTING THE DATA
Pressing of VOLUME sor tbutton will change the value of data.
When QA02 is initialized, items “OPT0”and “OPT1”of DESIGN MODE are set to the data of the representative model of this
chassis family.
Therefore, because ON-SCREEN specification remains in the state of the representative of model. This model is required to
reset the data of items “OPT0”and “OPT1”.

–10 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
ELECTRICAL ADJUSTMENTS
1. Enter the service mode, then select any register item.
2. Press the TV/VIDEO button on the Remote until the black cross-bar pattern ap-
pears on the screen.
3. Adjust the FOCUS control (on T461) for well defined scanning lines on the picture
screen.
FOCUS VR ADJ
SUB-BRIGHTNESS
(BRTC)
Note: Constrict the picture height
until the vertical retrace line
appears adjusting the item
HIT (HEIGHT).
1. Set CONTRAST to minimum, and
BRIGHTNESS to center by adjusting
user controls.
2. Set the TV in service mode to get white
cross-bar of inside pattern.
3. Select BRTC (brightness correction),
and adjust the ;–/+ button to reduce
the value so that white portion of inside
pattern slightly light.
4. Adjust ;–/+ button to increase the
data value of BRTC, and set it just
before the difference between the belt of
vertical retrace and the border of black
portion of inside pattern is visible.
After that, return vertical height and
contrast.
ITEM ADJUSTMENT PROCEDURE
Belt of vertical retrace
HORIZONTAL POSITION
ADJUSTMENT (HPOS)
VERTICAL POSITION
ADJUSTMENT (VPOS)
1. Set the TV in service mode, and get
black or white cross-bar signal with
VIDEO button on remote hand unit.
2. Select either HPOS (Horizontal
picture phase) or VPOS (Vertical
picture phase) with CHANNEL s, t
buttons, and adjust horizontal or
vertical picture position in the center
of screen with VOLUME ;–/+
buttons.
VERTICAL AMPLITUDE
ADJUSTMENT (HIT)
1. Set the TV in service mode, and get
black or white cross-hatch signal
with VIDEO button on remote hand
unit.
2. Select HIT (Vertical amplitude) with
CHANNEL s, tbuttons, and adjust
vertical amplitude with VOLUME
;–/+ buttons so that vertical am-
plitude lacks a little.
3. Adjust vertical amplitude with VOL-
UME ;–/+ buttons so that the first
bar on cross-hatch signal touches
edge of screen.
The first

–11 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
ITEM ADJUSTMENT PROCEDURE
WHITE BALANCE
ADJUSTMENT
•CUTOFF ADJUSTMENT
(RCUT)
(GCUT)
(BCUT)
•DRIVE ADJUSTMENT
(GDRV)
(BDRV)
1. Set Contrast to 40, and brightness to +20 by picture control.
2. Set the TV in service mode, and get the inside W/B adjusting signal with VIDEO
button.
3. Select RCUT, GCUT and BCUT with CHANNEL s, tbuttons, to set individual
values to Initial reference data, and to set GDRV and BDRV to Initial reference
data with VOLUME ;–/+ buttons (See page 16).
4. Press -/- - button on the remote control and rotate Screen VR to get one slight
horizontal line on screen.
Note: Every pressing of -/- - button provides Horizontal line picture and Normal
picture alternately.
5. Press -/- - button to release horizontal line picture, and select the two other
colours which did not light in the above step with CHANNEL s, tbuttons. Then
tap VOLUME ;–/+ buttons so that three colours slightly light in the same level.
XTo correct white balance in light area,
select GDRV and BDRV with CHANNEL
s, tbuttons to adjust.
XTo correct white balance in dark area,
perform fine adjustment of RCUT, GCUT
and BCUT.
Light area check
(to show white)
Dark area check
(to show black)
NOTE: It is released built-in test pattern by changing the adjustment item for some model.
In this case, select the adjustment item with channel stbuttons first and then select the built-in test pattern with
-/- - button.

–12 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
S1E: Series (Reference factory adjustment)
1 AFT/AGC ADJUSTMENT
(Measuring point) TP-13/TP-14
(Input frequency) CW: 38.00 [MHz] 95dBµV at 75Ω load
(Adjusting method)
1) Open link of IF out.
2) Input 1000pf cap. to link at tuner side to ground.
3) Input frequency after link. CW: 38.00 [MHz] 95dBµµ
µµ
µV at 75Ω Ω
Ω Ω
Ω load
4) Power On
5) Select RFAGC key, on screen display "RAGC OK, Coil OK"
6) If both display OK, adjustment finish; If any one display NG contine as follow
7) Press "0" key display "COIL PRESET"
8) Adjust L161 to 2.5 V±0.5V at TP13
9) Press "0" key display "COIL OK"
10) Press RFAGC key on screen display "REAGC ADJUSTING" for 3 secs only
11) DVM display 2.0±1.0V at TP14
12) On screen display "RFAGC OK, Coil OK"
13) Power Off.
AFT SPEC : 2.5±0.5V (TP13)
AGC SPEC: 2.0±1.0V (TP14)
2 SUB COLOUR CONTRAST (SCNT)
(Measuring point)
(Adjusting signal) NO ADJUSTMENT
(Adjusting method)
3 SUB BRIGHT (BRTC)
(Adjusting signal) Sub Bright (PAL or NTSC) signal.
(Adjusting method)
1) Set user control to the standard 1.
2) Change BRTC data to set black collapse numbers by eye check.
SPEC 4±1.5 bars
*Note: This item to adjust last
4 SUB COLOUR CENTER (COLP)
(Measuring point)
(Adjusting signal) NO ADJUSTMENT
(Adjusting method)
5 SUB TINT CENTER (FOR M-NTSC MODEL) (TNTC)
(Measuring point) Q501 #22 (B-OUT)
(Adjusting signal) Sub Bright (NTSC) signal *Note: For Thailand model use Video input
(Adjusting method) Change TNTC data to adjust the 5th pointion to the 6th level of B-Y signal and the 7th level differ-
ence should regulate to 2:1
SPEC: –5.0°±5°
*Note: This ITEM Adjust before (COLC)
–5°
1
2
#5 #6 #7

–13 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
6 SUB COLOUR NTSC (COLC)
(Measuring point) Q501 #22 (B-OUT)
(Adjusting signal) Sub Bright (NTSC) signal *Note: For Thailand model use Video input
(Adjusting method)
1) Set BUS date of Q501 to the same value as that SUB TINT adjustment.
2) Set user control to the standard 1.
3) Change COLC data to adjust the 6th peak amplitude of rainbow colour bar.
4) Adjust the amplitude of colour bar.
(p-p value of the upper half)
7 WHITE BALANCE ADJUSTMENT
(Adjusting method)
1) Set user control to the standard 1
2) BUS date of Q501
GDRV→Initial value (40H)
BDRV→Initial value (40H)
RCUT→Initial value (20H)
GCUT→Initial value (20H)
BCUT→Initial value (20H)
3) Set the mode to the one horizontal line mode
MUTE
BRIGHT
4) Change SCREEN VR to set it so that one of the line R, G and B will light slightely
5) Change CUT-OFF data to set it so that each one of R, G and B will light slighty (for about white)
6) Release the H.Line mode.
7) Change B/G drive data and R/G/B CUT-OFF data to adjust white balance in bright area and dark area.
* Bright area (High-light area): 30FL
* Dark area (Low light area): 4FL
SPEC Hight-light area: 11500°K+0.0075uv
Low-lignt area: 10500°K+0.0150uv
8 SUB COLOUR CENTER (COLS) (SECAM) (For models M, MJ, R, TR only)
(Measuring point) Q501 #22 (B-OUT)
(Adjusting signal) SECAM COLOUR BAR
(Adjusting method) Adjusting the amplitude of B-Y (Mute the picture in adjustment)
Spec: 1.75±0.2V
Value
Value
1.4±0.2 Vpp

–14 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
9 SECAM BELL FILTER ADJUSTMENT
(Measureing point)
(Adjusting signal) NO ADJUSTMENT
(Adjusting method)
10 SECAM R-Y ADJUSTMENT (For models M, MJ, R, TR only)
(Measuring point) Q501 #20 R-Y OUT
(Adjusting signal) Colour bar (SECAM) signal
(Adjusting method) Adjust (SRY) the level of the monochrome signal part must be a match to the level of horizontal
blanking signal.
Spec: 0±10 mVpp
11 SECAM B-Y ADJUSTMENT (For models M, MJ, R, TR only)
(Measureing point) Q501 #22 R-Y OUT
(Adjusting signal) Colour bar (SECAM) signal
(Adjusting method) Adjust (SBY) the level of the monochrome signal part must be a match to the level of horizontal
blanking signal.
Spec: 0±10 mVpp
12 VERTICAL POSITION
(Input signal) WG Philip Pattern (Do not use French SECAM)
(Measurement place) On Picture
(Setting) Contrast=Max. Bright=Center. Colour=Center
(Adjusting method) Adjust VPOS upper and lower position on Philips pattern may become a center. (Turn the direction of
CPT to the south or the north when adjusting. Adjust the amount offsetting if it is not possible to do)
13 VERTICAL HEIGHT
(Input signal) WG Philip Pattern (Do not use French SECAM)
(Measurement place) On Picture
(Setting) Contrast=Max. Bright=Center Colour=Center
(Adjusting method) Adjust the Sub address HIT on Philips pattern may hide frag of the upper and lower side in exactly.
14 HORIZONTAL POSITION
(Input signal) WG Philip Pattern (Do not use French SECAM)
(Measurement place) On Picture
(Setting) Contrast=Max. Bright=Center Colour=Center
(Adjusting method) Adjust the sub address HPOS on Philips pattern may become the center location (Minimize D-C in
the adjustment magnetic field on CPT.)

–15 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
CIRCUIT CHECK
HIGH VOLTAGE CHECK
CAUTION: There is no HIGH VOLTAGE ADJUSTMENT on this chassis. Checking should be done following the steps
below.
1. Connect an accurate high voltage meter to the second anode of the picture tube.
2. Turn on the receiver. Set the BRIGHTNESS and CONTRAST controls to minimum (zero beam current).
3. High voltage must be measured below (B) kV.
Refer to table-1 for high voltage (B).
(See SETTING & ADJUSTING DATA on page 16)
4. Vary the BRIGHTNESS control to both extremes to be sure the high voltage does not exceed the limit under any conditions.

– 16 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
SETTING & ADJUSTING DATA
20"
HIGH VOLTAGE AT ZERO BEAM: (A) 25.7 kV
MAX HIGH VOLTAGE: (B) 27.5 kV
AV VOLTAGE (C) 110~240 V
CHAPTER 2 SPECIFIC INFORMATIONS
SAFETY INSTRUCTIONS
Table-1
SERVICE MODE
ADJUSTING ITEMS AND DATAS IN THE SERVICE MODE:
Table-2
DESIGN MODE
ADJUSTING ITEMS AND DATAS IN THE DESIGN MODE:
Data
Item Name of adjustment Preset Data 20" Remarks
Table-3
* There are no adjusting items in the design mode.
Item Adjustment Reference data
RCUT
GCUT
BCUT
GDRV
BDRV
BRTC
COLC
TNTC
COLP
COLS
SCNT
HPOS
VPOS
HIT
VLIN
SRY
SBY
RAGC
R CUTOFF (B/W)
G CUTOFF (B/W)
B CUTOFF (B/W)
G DRIVE
B DRIVE
SUB BRIGHT CEN
SUB COLOUR CEN NTSC
SUB TINT CEN
SUB COLOUR CEN PAL
SUB COLOUR CEN SECAM
SUB CONTRAST
50Hz H-POSITION
V-POSITION
HEIGHT
V-LINEARITY
SECAM R-Y
SECAM-B-Y
RF AGC
20H
20H
20H
40H
40H
40H
40H
40H
FFH
40H
08H
0EH
03H
20H
08H
09H
05H
1AH
Data
←
←
←
←
←
←
←
←
←
←
06H
0FH
←
1DH
←
←
←
←

–17 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
LOCATION OF CONTROLS
Names of Parts
a
b
c
d
e
f
Main power on/off
Infrared sensor
Power indicator
Menu open
Channel up
Channel down
1
2
3
4
5
6
7
8
9
0
Power on/standby
Direct select
Position down/up
Volume down/up
Level down/up
Digit select
Menu open
Menu select
Sound mute
On-screen on/off
TV/VIDEO select
Picture control
Mono bilingual
select
MENU
0~9
-/+
-/+
-/--
MENU
CALL
I/II
TV Set Remote Controller
L
a
d
f
c
be
VIDEO AUDIO
R
MENU
TOSHIBA
TOSHIBA
!¡
!™
!£
CALL
–/--
1
4
7
2
5
8
0
3
6
9
MENU
0
3
7
5
6
1
2
!¡
4
5
!™
8
9

–18 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
Manual Search
Select Position 12.
Press 3repeatedly until 12 is displayed.
Or, press 6twice to display “--”on the screen then
press the “1”and “2”buttons (2) in this order.
Press 7repeatedly to display the D5 screen. Press
8and select “SEARCH”. Press 5to search. Pressing
“-”searches for channels at lower frequencies while
pressing “+”searches for channels at higher frequen-
cies.
When Channel 12 is found, press 8to select “a”.
Press “+”5to complete the presetting.
Store Position
Select Position 12.
Press 2or 3to find the position preset for Channel
12.
When Channel 12 is selected, press 7repeatedly to
display the D5 screen. Press 8and select “POSI-
TION”. Press 5and set “POSITION”to P12.
Pressing “-”and “+”respectively decreases and in-
creases the Position number.
When Channel 12 is found, press 8to select
“MEMORY”. Press “+”5to complete the presetting.
PROGRAMMING CHANNEL MEMORY
•For easy Channel selection, the chosen Position should have the same number as Channel stored there. For this
operation, you may use the “SEARCH”and “SKIP”functions.
Example : Presetting Channel 12 to Position 12
Channel Preset
Auto search memory (ASM)
All the channels that can be received are preset
automatically.
Select the starting position for ASM. Press 2or 3.
Set the correct broadcast system for your region.
Press 7repeatedly to call up the “SET UP”menu D5.
Set “COLOR”to “AUTO”and set “SOUND”according
to the table on page 6 of Owner's Manual using 8and
5.
Select “ASM”, then press 5(+) to start the search.
When the TV screen returns to the start position, the
procedure is complete.
1
2
3
1
2
3
1
2
3
Manual Search and Changing the assigned
position

–19 –
GENERAL ADJUSTMENTS
SPECIFIC INFORMATIONS
•Under some reception conditions, fine tuning may be necessary to improve the picture quality. In such cases, adjust the
manual fine tuning (MFT).
•If the signal frequency is unstable due to environmental conditions, use auto fine tuning.
Skip Function
If you set “SKIP ON”for unnecessary Position numbers, these
will be skipped when selecting channels using 3.
Example : Skipping Channel 13
Select Position 13 using the same method for select-
ing Position 12 (previous page).
Press 7repeatedly to display the D5 screen. Press
8and select “SKIP”.
Press 5to switch the “SKIP”setting from “OFF”to “ON”.
This completes the setting for skipping Position 13.
Note:
•When “SKIP”is ON, the Position number is prefixed by
“*”.
Example: *13. To confirm this, select Position 13 using
the 6and 2buttons.
•If you want to restore a skipped position number,
select it using the 6and 2buttons then switch the
“SKIP” setting to “OFF” as in step 2 above.
Manual fine tuning (MFT)
Press 7repeatedly to display the D6 screen.
Press 8and select “MFT”. Press 5to start fine tun-
ing. Pressing “-”fine tunes to a lower frequency while
pressing “+”fine tunes to a higher frequency.
1
Auto fine tuning (AFT)
Press 7repeatedly to display the D6 screen.
Press 8and select “AFT”. Press 5to switch it to “ON”.
This completes the setting.
Note:
•When you operate MFT, AFT is switched OFF
automatically. If you switch on AFT after fine tuning with
MFT, MFT may be cancelled.
•AFT may be set independently for each Position.
1
2
2
1
2

SPECIFIC INFORMATIONS
Location Parts No. Description
No.
Location Parts No. Description
No.
– 20 –
SPECIFIC INFORMATIONS
CAPACITORS
C101 24796479 ELECTROLYTIC, 35V 4.7UF M
C102 24797101 ELECTROLYTIC, 50V 100UF M
C103 24232103 CERAMIC DISC, 50V F 0.01UF Z
C104 24797100 ELECTROLYTIC, 50V 10UF M
C105 24590102 PLASTIC FILM, 50V 1000PF J
C106 24794221 ELECTROIYTIC, 16V 220UF M
C108 24538474 PLASTIC FILM, 50V 0.47UF J
C116 24590104 PLASTIC FILM, 50V 0.1UF J
C118 24474102 CERAMIC, 50V B 1000PF K
C129 24474102 CERAMIC, 50V B 1000PF K
C150 24232103 CERAMIC DISC, 50V F 0.01UF Z
C161 24797478 ELECTROLYTIC, 50V 0.47UF M
C162 24212102 CERAMIC DISC, 50V B 1000PF K
C166 24232103 CERAMIC DISC, 50V F 0.01UF Z
C167 24763101 ELECTROLYTIC, 16V 100UF M
C168 24794100 ELECTROLYTIC, 16V 10UF M
C170 24232103 CERAMIC DISC, 50V F 0.01UF Z
C180 24797229 ELECTROLYTIC, 50V 2.2UF M
C181 24232103 CERAMIC DISC, 50V F 0.01UF Z
C182 24797101 ELECTROLYTIC, 50V 100UF M
C212 24797010 ELECTROLYTIC, 50V 1UF M
C216 24797010 ELECTROLYTIC, 50V 1UF M
C221 24473100 CERAMIC, 50V 10PF J
C222 24473100 CERAMIC, 50V 10PF J
C223 24473100 CERAMIC, 50V 10PF J
C224 24797100 ELECTROLYTIC, 50V 10UF M
C225 24590104 PLASTIC FILM, 50V 0.1UF J
C226 24590104 PLASTIC FILM, 50V 0.1UF J
C233 24073077 ELECTROLYTIC, 50V 0.1UF M 3A
C301 24538154 PLASTIC FILM, 50V 0.15UF J
C302 24590152 PLASTIC FILM, 50V 1500PF J
C303 24538334 PLASTIC FILM, 50V 0.33UF J
C305 24617912 ELECTROLYTIC, 50V 2.2UF K 3A LI
C306 24073043 ELECTROLYTIC, 16V 2200UF M 3A
C307 24693473 PLASTIC FILM, 100V 0.047UF J
C308 24668101 ELECTROLYTIC, 35V 100UF M 3A
C309 24590102 PLASTIC FILM, 50V 1000PF J
C310 24796102 ELECTROLYTIC, 35V 1000UF M
C311 24214681 CERAMIC DISC, 500V B 680PF K
C313 24082057 PLASTIC FILM, 100V 0.22UF J
C314 24590473 PLASTIC FILM, 50V 0.047UF J
C317 24214471 CERAMIC DISC, 500V B 470PF K
C318 24212102 CERAMIC DISC, 50V B 1000PF K
C320 24668101 ELECTROLYTIC, 35V 100UF M 3A
C370 24794101 ELECTROLYTIC, 16V 100UF M
C371 24794220 ELECTROLYTIC, 16V 22UF M
C403 24590822 PLASTIC FILM, 50V 8200PF J
C404 24797478 ELECTROLYTIC, 50V 0.47UF M
C408 24590183 PLASTIC FILM, 50V 0.018UF J
C409 24212221 CERAMIC DISC, 50V B 220PF K
C410 24693472 PLASTIC FILM, 100V 4700PF J
C417 24214102 CERAMIC DISC, 500V B 1000PF K
C420 24666220 ELECTROLYTIC, 16V 22UF M 3A
C421 24666470 ELECTORLYTIC, 16V 47UF M 3A
C430 24232103 CERAMIC DISC, 50V F 0.01UF Z
C431 24794471 ELECTROLYTIC, 16V 470UF M
C432 24232103 CERAMIC DISC, 50V F 0.01UF Z
C433 24666100 ELECTROLYTIC, 10V 10UF M 3A
C435 24797479 ELECTROLYTIC, 50V 4.7UF M
C439 24232103 CERAMIC DISC, 50V F 0.01UF Z
C440 24082428 PLASTIC FILM, 1250VH 9800PF H
C442 24082968 PLASTIC FILM, 250V 0.36UF J
C445 24828563 PLASTIC FILM, 200V 56000PF J
C446 24679220 ELECTROLYTIC, 250V 22UF M 3A
C448 24640908 ELECTROLYTIC, 160V 33UF M 3A LI
C449 24666101 ELECTROLYTIC, 16V 100UF M 3A
C463 24212152 CERAMIC DISC, 50V B 1500PF K
C470 24794220 ELECTROLYTIC, 16V 22UF M
C472 24538474 PLASTIC FILM, 50V 0.47UF J
C504 24590104 PLASTIC FILM, 50V 0.1UF J
C505 24590104 PLASTIC FILM, 50V 0.1UF J
C511 24797010 ELECTROLYTIC, 50V 1UF M
C512 24212222 CERAMIC DISC, 50V B 2200PF K
C516 24232103 CERAMIC DISC, 50V F 0.01UF Z
C517 24763101 ELECTROLYTIC, 16V 100UF M
C521 24590104 PLASTIC FILM, 50V 0.1UF J
C522 24590104 PLASTIC FILM, 50V 0.1UF J
C523 24590104 PLASTIC FILM, 50V 0.1UF J
C524 24797101 ELECTROLYTIC, 50V 100UF M
C525 24232103 CERAMIC DISC, 50V F 0.01UF Z
C526 24590222 PLASTIC FILM, 50V 2200PF J
C527 24353100 CERAMIC DISC, 50V CH 10PF C
C528 24206228 ELECTROLYTIC, 50V 0.22UF M 7L 3A
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY
PRECAUTION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL.
CAUTION: The international hazard symbols “ ” in the schematic diagram and the parts list designate com-
ponents which have special characteristics important for safety and should be replaced only with types identical to
those in the original circuit or specified in the parts list. The mounting position of replacements is to be identical with
originals. Before replacing any of these components, read carefully the PRODUCT SAFETY NOTICE. Do not
degrade the safety of the receiver through improper servicing.
NOTICE:
• The part number must be used when ordering parts, in order to assist in processing, be sure to include the Model
number and Description.
• The PC board assembly with *mark is no longer available after the end of the production.
Model : 20A3VX
Capacitors ............. CD : Ceramic Disk PF : Plastic Film EL : Electrolytic
Resistors ............... CF : Carbon Film CC : Carbon Composition MF : Metal Film
OMF : Oxide Metal Film VR : Variable Resistor FR : Fusible Resistor
(All CD and PF capacitors are ±5%, 50V and all resistors, ±5%, 1/6W unless otherwise noted.)
CHASSIS AND CABINET REPLACEMENT PARTS LIST