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TOSHIBA FILE NO.050-200118
SERVICE MANUAL
COLOR TELEVISION
20AR21
20AR31
MT S ST ER EO
AUT O V OL T AGE
AUT O V OL T AGE
DOCUMENT CREATED IN JAPAN, OCT., 2001
S49F614LK20A/
20A R 21 20A R 31
COLOR TELEVISION
Chassis No. MSA
AUT O V OL T AGE
MT S ST ER EO
AUT O V OL T AGE
20AR21
MODELS 20AR31
In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its
original condition and only parts identical to those specified should be used.
CONTENTS
Page
» ELECTRICAL SPECIFICATIONS ......................................................................................................... 1
» IMPORTANT SERVICE SAFETY PRECAUTION ................................................................................. 2
» LOCATION OF USER'S CONTROL ..................................................................................................... 4
» INSTALLATION AND SERVICE INSTRUCTIONS ................................................................................ 5
» CHASSIS LAYOUT ............................................................................................................................. 13
» BLOCK DIAGRAM .............................................................................................................................. 15
» SCHEMATIC DIAGRAMS ................................................................................................................... 20
» PRINTED WIRING BOARD ASSEMBLIES ........................................................................................ 28
» REPLACEMENT PARTS LIST ............................................................................................................ 32
» PACKING OF THE SET ...................................................................................................................... 39
ELECTRICAL SPECIFICATIONS
POWER INPUT ........................................ 110-220 V AC 50/60 Hz SPEAKER
POWER RATING SIZE ................................................................ 9 × 5 cm (Round)
20AR21 ................................................................................ 72 W VOICE COIL IMPEDANCE
20AR31 ................................................................................ 79 W 20AR21 ....................................................... 32 ohm at 400 Hz
PICTURE SIZE .......................................... 1,192 cm2 (185sq inch) 20AR31 ......................................................... 4 ohm at 400 Hz
CONVERGENCE ............................................................. Magnetic ANTENNA INPUT IMPEDANCE
SWEEP DEFLECTION .................................................... Magnetic VHF/UHF ..................................................... 75 ohm Unbalanced
FOCUS ............................................................... QPF Electrostatic TUNING RANGES
INTERMEDIATE FREQUENCIES VHF-Channels ............................................................... 2 thru 13
Picture IF Carrier Frequency ..................................... 45.75 MHz UHF-Channels ............................................................ 14 thru 69
Sound IF Carrier Frequency ...................................... 41.25 MHz CATV Channels ........................................................... 1 thru 125
Color Sub-Carrier Frequency .................................... 42.17 MHz
(Nominal)
AUDIO POWER
OUTPUT RATING Specifications are subject to change without
20AR21 ................................... 1.5 + 1.5 W (at 10% distortion) prior notice.
20AR31 ................................... 3.0 + 3.0 W (at 10% distortion)
1
1
20AR21
20AR31
IMPORTANT SERVICE SAFETY PRECAUTION
Ë Service work should be performed only by qualified service technicians who are thoroughly
familiar with all safety checks and the servicing guidelines which follow:
WARNING X-RADIATION AND HIGH VOLTAGE LIMITS
1. For continued safety, no modification of any circuit 1. Be sure all service personnel are aware of the
should be attempted. procedures and instructions covering X-radiation. The
2. Disconnect AC power before servicing. only potential source of X-ray in current solid state
3. Semiconductor heat sinks are potential shock TV receivers is the picture tube. However, the picture
hazards when the chassis is operating. tube does not emit measurable X-Ray radiation, if
4. The chassis in this receiver has two ground systems the high voltage is as specified in the "High Voltage
which are separated by insulating material. The non- Check" instructions.
isolated (hot) ground system is for the B+ voltage It is only when high voltage is excessive that X-
regulator circuit and the horizontal output circuit. The radiation is capable of penetrating the shell of the
isolated ground system is for the low B+ DC voltages picture tube including the lead in the glass material.
and the secondary circuit of the high voltage The important precaution is to keep the high voltage
transformer. below the maximum level specified.
To prevent electrical shock use an isolation 2. It is essential that servicemen have available at all
transformer between the line cord and power times an accurate high voltage meter.
receptacle, when servicing this chassis. The calibration of this meter should be checked
periodically.
SERVICING OF HIGH VOLTAGE SYSTEM 3. High voltage should always be kept at the rated value
-no higher. Operation at higher voltages may cause
AND PICTURE TUBE
a failure of the picture tube or high voltage circuitry
When servicing the high voltage system, and;also, under certain conditions, may produce
remove the static charge by connecting a radiation in exceeding of desirable levels.
4. When the high voltage regulator is operating properly
10k ohm resistor in series with an insulated there is no possibility of an X-radiation problem. Every
wire (such as a test probe) between the pic- time a color chassis is serviced, the brightness should
ture tube ground and the anode lead. (AC be tested while monitoring the high voltage with a
line cord should be disconnected from AC meter to be certain that the high voltage does not
outlet.) exceed the specified value and that it is regulating
correctly.
1. Picture tube in this receiver employs integral implosion 5. Do not use a picture tube other than that specified or
protection. make unrecommended circuit modifications to the
2. Replace with tube of the same type number for high voltage circuitry.
continued safety. 6. When trouble shooting and taking test measurements
3. Do not lift picture tube by the neck. on a receiver with excessive high voltage, avoid being
4. Handle the picture tube only when wearing unnecessarily close to the receiver.
shatterproof goggles and after discharging the high Do not operate the receiver longer than is necessary
voltage anode completely. to locate the cause of excessive voltage.
2
20AR21
20AR31
IMPORTANT SERVICE SAFETY PRECAUTION
(Continued)
BEFORE RETURNING THE RECEIVER · Connect the resistor connection to all exposed metal
parts having a return to the chassis (antenna, metal
(Fire & Shock Hazard) cabinet, screw heads, knobs and control shafts,
Before returning the receiver to the user, perform escutcheon and etc.) and measure the AC voltage
the following safety checks. drop across the resistor.
AII checks must be repeated with the AC ine cord
1. Inspect all lead dress to make certain that leads are plug connection reversed. (If necessary, a non-
not pinched or that hardware is not lodged between polarized adapter plug must be used only for the
the chassis and other metal parts in the receiver. purpose of completing these check.)
2. Inspect all protective devices such as non-metallic Any current measured must not exceed 0.5 milliamp.
control knobs, insulating materials, cabinet backs, Any measurements not within the limits outlined
adjustment and compartment covers or shields, above indicate of a potential shock hazard and
isolation resistor-capacity networks, mechanical corrective action must be taken before returning the
insulators and etc. instrument to the customer.
3. To be sure that no shock hazard exists, check for
leakage current in the following manner.
· Plug the AC cord directly into a 110~220 volt AC
outlet, (Do not use an isolation transformer for this
test).
· Using two clip leads, connect a 1.5k ohm, 10 watt
resistor paralleled by a 0.15µF capacitor in series with
all exposed metal cabinet parts and a known earth
ground, such as electrical conduit or electrical ground
connected to earth ground.
· Use an AC voltmeter having with 5000 ohm per volt,
or higher, sensitivity to measure the AC voltage drop
across the resistor. 1.5k ohm
10W
0.15µF
TEST PROBE
TO EXPOSED CONNECT TO
METAL PARTS KNOWN EARTH
GROUND
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
SAFETY NOTICE
Many electrical and mechanical parts in television For continued protection, replacement parts must be
receivers have special safety-related characteristics. identical to those used in the original circuit. The use of
These characteristics are often not evident from visual substitute replacement parts which do not have the same
inspection, nor can protection afforded by them be safety characteristics as the factory recommended
necessarily increased by using replacement components replacement parts shown in this service manual, may
rated for higher voltage, wattage, etc. create shock, fire, X-radiation or other hazards.
Replacement parts which have these special safety
characteristics are identified in this manual; electrical
components having such features are identified by "å"
and shaded areas in the Replacement Parts Lists and
Schematic Diagrams.
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
3
20AR21
20AR31
LOCATION OF USER'S CONTROL
Front Panel (20AR21)
VIDEO/AUDIO TERMINALS
(VIDEO/AUDIO terminals are also
provided on the rear.)
(20AR31)
MT S S T ER EO
AUT O V OL T AGE
VIDEO/AUDIO TERMINALS
POWER
Press On.
Press again Off. CHANNEL UP/DOWN
( ) Selects next higher channel.
( ) Selects next lower channel.
SENSOR AREA FOR VOLUME UP/DOWN
REMOTE CONTROL ( )Increases sound.
( )Decreases sound.
MENU
Press Accesses MAIN MENU.
Press again Exits MAIN MENU.
Basic Remote Control Functions
Infrared Transmitter Window
POWER INPUT
Press On. Press Switch to external video input
Press again Off. mode.
Press again Switch to TV mode.
REMOTE KEYPAD (20AR31)
Accesses any channel from keypad. Press Switch to external video
RETURN INPUT 1 mode.
Returns to previous channel. Press 2 times Switch to external
video INPUT 2 mode.
Press 3 times Switch back to the
VOLUME UP/DOWN original TV mode.
(+) Increases sound. RETURN
() Decreases sound.
· In menu mode, changes or selects CHANNEL UP/DOWN
the TV adjustments. ( ) Selects next higher channel.
( ) Selects next lower channel.
MUTE
Press Mutes sound. · Moves the " " mark of the MENU
Press again Restores sound. screen.
· CLOSED CAPTION appears when
sound is muted.
MENU
Press Accesses MAIN MENU.
Press again Exits MAIN MENU.
DISPLAY
Press Displays receiving channel for
4 seconds.
CT-818 Press again Removes display.
· Temporarily displays receiving
channel when in Closed Caption
mode.
4
20AR21
20AR31
INSTALLATION AND SERVICE INSTRUCTIONS
Note: (1) When performing any adjustments to resistor controls and transformers use non-metallic
screwdrivers or TV alignment tools.
(2) Before performing adjustments, the TV set must be on at least 15 minutes.
CIRCUIT PROTECTION HIGH VOLTAGE CHECK
The receiver is protected by a 3.15A fuse (F701), High voltage is not adjustable but must be checked
mounted on PWB-A, wired into one side of the AC to verify that the receiver is operating within safe
line input. and efficient design limitations as specified checks
should be as follows:
+B DC REGULATOR CONFIRMATION
The + B DC output voltage adjustment is not included 1. Connect an accurate high voltage meter between
in this circuit.However, should confirmation be ground and anode of picture tube.
reguired proceed as follows. 2. Operate receiver for at least 15 minutes at 110~220V
AC line voltage, with a strong air signal or a properly
1. Actuate receiver with 220V AC input voltage. tuned in test signal.
2. Receive a local channel. 3. Receve a good local channel.
3. Connect positive lead of digital voltmeter to C754 4. The voltage should be approximately, 25.5kV (at
positive side on PWB-A ; negative lead to chassis pictuer MAX Bright center condition).
ground. If a correct reading cannot be obtained, check circuitry
4. Confirm this voltage reading is as below. for malfunctioning components.
CAUTION: The reading should be within +130.0 ± 2.0V
DC to ensure normal function and circuitry
reliability.
X-RADIATION PROTECTOR CIRCUIT TEST
After service has been performed on the horizontal
deflection system, high voltage system, B+ system,
test the X-Radiation protection circuit to ascertain
proper operation as follows:
1. Apply 220V AC using a variac transformer for accurate
input voltage.
2. Allow for warm up and adjust all customer controls
for normal picture and sound.
3. Receive a good local channel.
4. Connect a digital voltmeter to TP653 and make sure
that the voltmeter reads 21.4 ± 1.5 V.
5. Apply external 27.9V DC at TP653 by using an
external DC supply, TV must be shut off.
6. To reset the protector, unplug the AC cord and make
a short circuit between TP651 and TP652. Now make
sure that normal picture appears on the screen.
7. If the operation of the horizontal oscillator does not
stop in step 5, the circuit must be repaired before the
set is returned to the customer.
5
20AR21
20AR31
For adjustments of this model, the bus data is converted to various analog signals by the D/A converter
circuit.
Note: There are still a few analog adjustments in this series such as focus and master screen voltage.
Follow the steps below whenever the service adjustment is required. See "Table-B" to determine, if serv-
ice adjustments are required.
1. Service mode To enter the service mode and exit serv-
Before putting unit into the service mode, check that ice mode.
customer adjustments are in the normal mode. Use
the reset function in the video adjustment menu to Short JA137&JA138 for 1 Second and release to switch
ensure customer controls are in their proper (reset) to the service mode position, and the microprocessor is
position. in input mode.(Adjustment through the I2C bus control.)
To exit the service mode, turn the television off by
2. Service item selection pressing the power button.
Once in the service mode, press the Ch-up or Ch-
down button on the remote controller or at the set.
The service adjustment item will vary in increments
of one. Select the item you wish to adjust.
3. Data number selection
Press the Vol-up or down button to adjust the data
number.
SERVICE ADJUSTMENT ITEM DATA NUMBER
AGC: 25
Figure A.
6
20AR21
20AR31
SERVICE MODE
(1) In the Service Mode, Key is used to select the mode in the following oreder.
AGC & WHITE POINT SUB
GEOMETRIC ADJ. ADJ.
MODE MODE MODE
OFFSET
ADJ.
MODE
FEATURE IC MTS
OPTION OPTION ADJ.
MODE MODE MODE
AGC & WHITE POINT SUB
GEOMETRIC ADJ. ADJ.
MODE MODE MODE
AGC TAKE OVER POINT (AGC) W.P. RED OFFSET HIGH / MAX VOLUME (SUB-VOL)
OFFSET BLUE TONE (DRI-R-HI)
VERTICAL SLOPE (V-LIN) SUB CONTRAST (SUB-CON)
W.P. GREEN OFFSET HIGH /
VERTICAL AMP (V-AMP) OFFSET BLUE TONE (DRI-G-HI) SUB TINT (SUB-TINT)
VERTICAL SHIFT (V-CENT) W.P.BLUE OFFSET HIGH / SUB COLOUR (SUB-COL)
OFFSET BLUE TONE (DRI-B-HI)
VERTICAL ZOOM (V-ZOOM) SUB BRIGHTNESS (SUB-BRI)
W.P. RED MH / STD (DRI-R-MH)
HORIZONTAL SHIFT (H-CENT) SUB SHARPNESS (SUB-SHP)
W.P. GREEN MH / STD (DRI-G-MH)
EAST-WEST WIDTH (H-SIZE) MAX HOTEL VOLUME (HTL-VOL)
W.P. BLUE MH / STD (DRI-B-MH)
HORIZONTAL PARALLELOGRAM (EW//) HOTEL PROGRAM NO(HTL-PRG)
W.P. RED OFFSET ML /
EAST-WEST PARABOLA / WIDTH (PARA) OFFSET RED TONE (DRI-R-ML) BLUE BACK CONTRAST (BB-CON)
EAST-WEST UPPER CORNER W.P. GREEN OFFSET ML / OSD GRB REFERENCE (RGB)
PARABOLA (COR(U)) OFFSET RED TONE (DRI-G-ML)
BLACK LEVEL OFFSET R(CUT-R)
EAST-WEST LOWER CORNER W.P. BLUE OFFSET ML /
PARABOLA (COR(L)) OFFSET RED TONE (DRI-B-ML) BLACK LEVEL OFFSET G(CUT-G)
EAST-WEST TRAPEZIUM (TRAPE) W.P. RED OFFSET LOW (DRI-R-LO) CATHODE DRIVE LEVEL(CDL)
HORIZONTAL BOW (HB) W.P. GREEN OFFSET LOW (DRI-G-LO)
S-CORRECTION (S-COR) W.P. BLUE OFFSET LOW (DRI-B-LO)
7
20AR21
20AR31
OFFSET MTS
ADJ. ADJ.
MODE MODE
Y-D TIME (TV) [ YD ] (DL-TV) ATTENUATE INPUT SIGNAL LEVEL (ATT)
Y-D TIME (AV) [ YD ] (DL-AV) VCO FREE RUNNING FREQUENCY ADJ. (VCO)
INITIAL/DEFAULT LANGUAGE (INIT) STEREO, SAP, DBX FILTER ADJ. (FILTER)
FAO-MAX VOLUME (FAO-VOL) STEREO SEPARATION ADJUSTMENT (300HZ) (WIDEBAND)
ENERGY SAVE OFFSET (ESV_OFFS) STEREO SEPARATION ADJUSTMENT (3kHZ) (SPECTRAL)
CLOSE CAPTION POSITION (CCPOS) BASS LEVEL (BASS)
TREBLE LEVEL (TREBLE)
IC FEATURE
OPTION OPTION
MODE MODE
VERTICAL SCAN DISABLE (VSD) V-CHIP (V-CHIP)
BLACK STRETCH (BKS) MTS DECODING ENABLED (MTS)
AUTOMATIC VOLUME LEVELLING (AVL) DEMO MODE (DEMO)
FAST FILTER IF-PLL ( FFI ) REAL TIME CLOCK / ON TIMER (CLOCK)
ENABLE VERTICAL GUARD ( EVG ) ENERGY SAVE (E-SAVE)
EHT TRACKING MODE ( EHT ) PERSONAL PREFERENCE PROGRAM (P_PREF)
OVERSCAN SWITCH OFF (OSO) UNIVERSAL PLUS (UNIV+)
AUTO COLOUR LIMIT (ACL) SPEAKER ON/OFF (SPEAKER)
FORCED COLOUR-ON (FCO) FIXED AUDIO OUT (FAO)
VIDEO MUTE AT IDENT LOSS (VMI) VIEW TIMER (VIEW-TM)
VIDEO MUTE AT PROGRAM/SOURCE CHANGE (VMC) FRENCH LANGUAGE (FRENCH)
HOTEL MODE (HTL) EZ SETUP / AUTOPRESET (EZ-SETUP)
GAIN FM DEMODULATOR (BTSC) WHITE TEMP OR FAVORITE COLOR (W-TEMP)
CHARGE PUMP (CP) AV ENABLED OR DISABLED (AV)
FM WINDOW SELECTION (FMWS) AV2 ENABLED OR DISABLED (AV2)
SOUND MUTE BIT 0 (SM0) DYNAMIC SKIN CONTROL (DSK)
SOUND MUTE BIT 1 (SM1) RATIO PRE- AND OVERSHOOT BIT 0 (RPO0)
IF AGC SPEED BIT 0 (AGC0) RATIO PRE- AND OVERSHOOT BIT 1 (RPO1)
IF AGC SPEED BIT 1 (AGC1) GAIN FM DEMODULATOR (AGN)
PHI 1 TIME CONSTANT FOR FE (FOA-FE) AUTO SWITCH OFF ENABLED (AUTO-OFF)
PHI 1 TIME CONSTANT FOR FE (FOB-FE)
PHI 1 TIME CONSTANT FOR AV (FOA-AV)
PHI 1 TIME CONSTANT FOR AV (FOB-AV)
FORCED SLICING LEVEL FOR VERTICAL SYNC.(FSL)
FORWARD : CH DOWN KEY
SYNCHRONISATION OF OSD/TEXT DISPLAY (HP2)
REVERSE : CH UP KEY
RGB BLANK (RGBL) ( ) means OSD display.
Figure B: ADJUSTMENT CATEGORIES
1Press the CH DOWN/UP key on the remote controller to get ready to select the mode one by one.
2Press the CH DOWN/UP key on the remote controller to select the modes reversibly one by one.
3Using the VOLUME UP/DOWN key on the remote controller, the data can be modified.
(OSD disturbance can be erased by R/C display key)
8
20AR21
20AR31
SERVICE MODE
SERVICE DATA
ADJUST ITEM REMARK
POSITION RANGE INITIAL VALUE FIX/ADJ
AGC AGC TAKE OVER POINT 0~63 14 ADJ
V-LIN VERTICAL SLOPE 0~63 32 ADJ
V-AMP VERTICAL AMP 0~63 32 ADJ
V-CENT VERTICAL SHIFT 0~63 32 ADJ
V-ZOOM VERTICAL ZOOM 0~63 32 FIX
H-CENT HORIZONTAL SHIFT 0~63 32 ADJ
H-SIZE EAST-WEST WIDTH 0~63 32 FIX
EW// HORIZONTAL PARALLELOGRAM 0~63 32 FIX
PARA EAST-WEST PARABOLA / WIDTH 0~63 32 FIX
COR(U) EAST-WEST UPPER CORNER PARABOLA 0~63 32 FIX
COR(L) EAST-WEST LOWER CORNER PARABOLA 0~63 32 FIX
TRAPE EAST-WEST TRAPEZIUM 0~63 32 FIX
HB HORIZONTAL BOW 0~63 32 FIX
S-COR S-CORRECTION 0~63 0 FIX must be "17"
DRI-R-HI "W,P RED OFFSET HIGH / OFFSET BLUE TONE" 0~63 32 FIX must be "32"
DRI-G-HI W.P. GREEN OFFSET HIGH / OFFSET BLUE TONE 0~63 32 FIX must be "33"
DRI-B-HI W.P.BLUE OFFSET HIGH / OFFSET BLUE TONE 0~63 32 FIX must be "37"
DRI-R-MH W.P. RED MH / STD 0~63 25 FIX must be "32"
DRI-G-MH W.P. GREEN MH / STD 0~63 32 ADJ
DRI-B-MH W.P. BLUE MH / STD 0~63 32 ADJ
DRI-R-ML W.P. RED OFFSET ML / OFFSET RED TONE 0~63 32 FIX must be "32"
DRI-G-ML W.P. GREEN OFFSET ML / OFFSET RED TONE 0~63 32 FIX must be "32"
DRI-B-ML W.P. BLUE OFFSET ML / OFFSET RED TONE 0~63 32 FIX must be "25"
DRI-R-LO W.P. RED OFFSET LOW 0~63 32 FIX must be "32"
DRI-G-LO W.P. GREEN OFFSET LOW 0~63 32 FIX must be "22"
DRI-B-LO W.P. BLUE OFFSET LOW 0~63 32 FIX must be "19"
SUB-VOL MAX VOLUME 0~63 63 FIX must be "63"
SUB-CON SUB CONTRAST 0~63 63 FIX must be "54"
SUB-COL SUB COLOUR 0~63 32 ADJ
SUB-BRI SUB BRIGHTNESS 0~63 32 ADJ
SUB-TINT SUB TINT 0~63 32 ADJ
SUB-SHP SUB SHARPNESS 0~63 32 FIX must be "27"
HTL-VOL MAX HOTEL VOLUME 0~63 32 FIX
HTL-PRG HOTEL PROGRAM NO 0~125 or >125 for none 255 FIX
BB-CON BLUE BACK CONTRAST 0~15 10 FIX must be "5"
RGB OSD GRB REFERENCE 0~15 15 FIX must be "5"
CUT-R BLACK LEVEL OFFSET R 0~63 32 ADJ
CUT-G BLACK LEVEL OFFSET G 0~63 32 ADJ
CDL CATHODE DRIVE LEVEL 0~15 0 FIX must be "6"
DL-TV Y-D TIME (TV) [ YD ] 0~15 12 FIX must be "2"
DL-AV Y-D TIME (AV) [ YD ] 0~15 12 FIX must be "8"
INIT INITIAL/DEFAULT LANGUAGE 0(English), 1(Spanish), 0 FIX must be "1"
2(French)
FAO-VOL FAO-MAX VOLUME 0~63 63 FIX must be "63"
ESV_OFFS ENERGY SAVE OFFSET 0~63 10 FIX must be "20"
CCPOS CLOSE CAPTION POSITION 0~255 32 ADJ
ATT ATTENUATE INPUT SIGNAL LEVEL 0~15 10 FIX*
VCO VCO FREE RUNNING FREQUENCY ADJ. 0~63 32 FIX*
FILTER "STEREO, SAP, DBX FILTER ADJ. " 0~63 28 FIX* 20AR21=FIX
WIDEBAND STEREO SEPARATION ADJUSTMENT (300HZ) 0~63 32 FIX* 20AR31=ADJ
SPECTRAL STEREO SEPARATION ADJUSTMENT (3kHZ) 0~63 27 FIX*
BASS BASS LEVEL 0Å`15 8 FIX
TREBLE TREBLE LEVEL 0Å`15 8 FIX
VSD VERTICAL SCAN DISABLE 0 or 1 when item selected 0 FIX
BKS BLACK STRETCH 0(disable) or1(enable) 1 FIX
AVL AUTOMATIC VOLUME LEVELLING 0(disable) or1(enable) 1 FIX
FFI FAST FILTER IF-PLL 0(disable) or1(enable) 0 FIX
EVG ENABLE VERTICAL GUARD 0(disable) or1(enable) 1 FIX
EHT EHT TRACKING MODE 0(disable) or1(enable) 1 FIX
OSO OVERSCAN SWITCH OFF 0(disable) or1(enable) 0 FIX
ACL AUTO COLOUR LIMIT 0(disable) or1(enable) 0 FIX
FCO FORCED COLOUR-ON 0(disable) or1(enable) 0 FIX
VMI VIDEO MUTE AT IDENT LOSS 0(disable) or1(enable) 1 FIX
VMC VIDEO MUTE AT PROGRAM/SOURCE CHANGE 0(disable) or1(enable) 1 FIX
HTL HOTEL MODE 0(disable) or1(enable) 0 FIX
BTSC GAIN FM DEMODULATOR 0(disable) or1(enable) 0 FIX
CP CHARGE PUMP 0(fast tuning) or 1 0 FIX
(moderate speed tuning)
Table - A
9
20AR21
20AR31
SERVICE DATA
ADJUST ITEM REMARK
POSITION RANGE INITIAL VALUE FIX/ADJ
FMWS FM WINDOW SELECTION 0(disable) or1(enable) 0 FIX
SM0 SOUND MUTE BIT 0 (SM0) 0(disable) or1(enable) 1 FIX
SM1 SOUND MUTE BIT 1 0(disable) or1(enable) 0 FIX
AGC0 IF AGC SPEED BIT 0 0(disable) or1(enable) 1 FIX
AGC1 IF AGC SPEED BIT 1 0(disable) or1(enable) 0 FIX
FOA-FE PHI 1 TIME CONSTANT FOR FE 0(disable) or1(enable) 0 FIX
FOB-FE PHI 1 TIME CONSTANT FOR FE 0(disable) or1(enable) 0 FIX
FOA-AV PHI 1 TIME CONSTANT FOR AV 0(disable) or1(enable) 1 FIX
FOB-AV PHI 1 TIME CONSTANT FOR AV 0(disable) or1(enable) 1 FIX
FSL FORCED SLICING LEVEL FOR VERTICAL SYNC. 0(disable) or1(enable) 0 FIX
HP2 SYNCHRONISATION OF OSD/TEXT DISPLAY 0(disable) or1(enable) 0 FIX
RGBL RGB BLANK 0(disable) or1(enable) 0 FIX
V-CHIP V-CHIP 0(disable) or1(enable) 0 FIX
MTS MTS DECODING ENABLED 0(disable) or1(enable) 0 FIX* 20AR210/20AR311
DEMO DEMO MODE 0(disable) or1(enable) 1 FIX
CLOCK REAL TIME CLOCK / ON TIMER 0(disable) or1(enable) 1 FIX must be "1"
E-SAVE ENERGY SAVE 0(disable) or1(enable) 1 FIX
P_PREF PERSONAL PREFERENCE PROGRAM 0(disable) or1(enable) 0 FIX
UNIV+ UNIVERSAL PLUS 0(disable) or1(enable) 0 FIX
SPEAKER SPEAKER ON/OFF 0(disable) or1(enable) 0 FIX
FAO FIXED AUDIO OUT 0(disable) or1(enable) 0 FIX
VIEW-TM VIEW TIMER 0(disable) or1(enable) 1 FIX must be "1"
FRENCH FRENCH LANGUAGE 0(disable) or1(enable) 0 FIX
EZ-SETUP EZ SETUP / AUTOPRESET 0(AUTOPRESET) or 1 FIX
1(EZ SETUP)
W-TEMP WHITE TEMP OR FAVORITE COLOR 0(FC) or 1(WT) 0 FIX
AV AV ENABLED OR DISABLED 0(without ext. source) or 0 FIX
1(with external source)
AV2 AV2 ENABLED OR DISABLED 0(1 input) or 1(2 input) 0 FIX* 20AR210/20AR311
DSK DYNAMIC SKIN CONTROL 0(disable) or1(enable) 0 FIX
RPO0 RATIO PRE- AND OVERSHOOT BIT 0 0(disable) or1(enable) 0 FIX
RPO1 RATIO PRE- AND OVERSHOOT BIT 1 0(disable) or1(enable) 0 FIX
AGN GAIN FM DEMODULATOR 0(normal) or1(+6dB) 0 FIX
AUTO-OFF AUTO SWITCH OFF ENABLED 0(disable) or1(enable) 1 FIX
PON-CH 0(disable) or1(enable) 0 FIX
Table - A
Holding down to short JA137 & JA138 and turn on the main power SW will automatically write the initial values into
IC1003.
This is only can done when a new EEPROM is used. (Judge with the first 4 bytes.)
ADJUSTMENT
PART REPLACED NOTES
NECESSARY UNNECESSARY
IC801 X Data is stored in IC1003.
Holding down to short JA137 & JA138 and turn on the main
IC1003 power SW will automatically write the initial values into IC1003.
X
This is only can done when a new EEPROM is used. (Judge
with the first 4 bytes.)
CRT X Adjust items related to picture tube only.
Table - B
10
20AR21
20AR31
Ë SERVICE ADJUSTMENT
RF AGC Adjustment
1. Receive a good local channel.
2. Enter the service mode signal category and select
the service adjustment "AGC".
3. Set the data value to point where no noise or beat
appears.
4. Select another channel to confirm that no noise or
beat appears.
CHROMA ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
WAVEFORM 1 FINAL WAVEFORM
1 SUB-TINT (I2C 1. Receive the "Colour Bar" signal through AV in.
BUS CON- 2. Connect the oscilloscope to TP853 (Pin (5) of SAME LEVEL
TROL) P882) BLUE-OUT.
» Range : 100mV/div. (AC)(Use Probe 10:1)
» Sweep time : 10 µsec/div.
3. Call the "SUB-TINT" mode in service mode. Ad-
just the "SUB-TINT" bus data to obtain the wave- W Y CY G MG R B
form shown as Fig 1. Fig 1 Fig 2
4. "SUB-TINT" bus data decrease 4 steps to get fi-
nal waveform. (Fig 2.)
5. Clear the SERVICE mode.
HORIZONTAL AND VERTICAL DEFLECTION LOOP ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
2
1 V-SLOPE(I C 1. Receive Monoscope Pattern Signal.
BUS CON- 2. Call the "V-LIN" mode.
TROL) 3. Increase or decrease "V-LIN" by Volume key till
the horizontal line in the center of monoscope is
just at the position where the blanking starts.
2 V-CENTER (I2C 1. Call the "V-CENT" mode.
BUS CON- 2. Increase or decrease "V-CENT" by Volume key till
TROL) the picture is centered.
3 V - AMP (I2C 1. Call the "V-AMP" mode.
BUS CON- 2. Increase or decrease "V - AMP" by Volume key to
TROL) set overscan of 10.0% typical.
Adjustment Spec 10.0% range ±1%.
4 S-CORREC-
TION (I2C BUS FIXED DATA, NO NEED TO ADJUST.
CONTROL)
H - CENTER
5
1. Call the "H-CENT" mode.
2. Increase or decrease "H-CENT" by Volume key
to center the picture horizontal.
6 Focus 1. Receive the "Monoscope Pattern" signal.
adjustment 2. Press R/C to set Picture NORMAL condition.
3. Adjust the focus control to get the best focus.
11
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CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
1 CRT CUTOFF 1. Switch TV to VIDEO mode,BLUE BACK OFF, with
ADJUSTMENT NO VIDEO signal. 3.5Vdc
(I2C BUS 2. Press R/C to set Picture Normal condition.
CONTROL) 3. Connect the oscilloscope to Red OUT from
IC801.(TP47R)
Range : 1 V/Div (DC)
Sweep : 5 msec/Div
1V
4. Adjust SCREEN VR ,so that the tip of signal reach
0
3.5 Vdc + 0.1 Vdc.
2 SUB-BRIGHT- 1. Call " SUB-BRI" in service mode. (Receive Cross-
NESS hatch pattern with 5 black level windows)
ADJUSMENT 2. Adjust the " SUB BRIGHT " bus data in order that
(I2C BUS the line 1, 2 and 3 have the same darkness
CONTROL) wherelse line 4 is slightly brighter than line 1, 2 1 2 3 4 5
and 3 and finally line 5 will be the brighter than
line 4. 1, 2, 3 are in same black level.
3 WHITE BAL- 1. Receive the "Monoscope Pattern" signal. # 11,600° K X : 0.273
ANCE SERV- 2. Press R/C to set Picture NORMAL condition. Y : 0.280
ICE MODE 3. Connect the DC miliammeter between the TP 602
ADJ. (I2C BUS ( - ) TP 603 ( + ). ( MINOLTA COLOUR ANALYZER
CONTROL) 4. Check Beam current should be around (990µA) CA-100)
5. Set it to service mode and adjust the DRI-G-MH, *NOTE: Above DATA can be UP/
& DRI-B-MH data to have a colour temperature DOWN by volume key.
of 11,600°K ( white ).
6. Receive "WHITE" pattern, WITH BURST signal, LOW HIGH
and set BRIGHTNESS Y by generator, to ** 10 20" 1.8cd/m2 115cd/m2
cd/m2 (MINOLTA CA-100) by reducing LUMINATE
Y signal. * 11,600° K
7. Adjust "CUT-R" & "CUT-G" to get 11,600°K. Then DRI-GW="DRI-GS"DATA-5
go back NORMAL mode (HIGH BRIGHT**) to DRI-BW="DRI-BS" DATA-5
check colour temperature. If out of range, back
to (1).
Note: This adjustment must be done after
warming up the unit for 30 minutes or
longer with a beam current over 500µA.
DRI-R-MH=32 (FIXED)
DRI-G-MH=33 (FIXED)
DRI-B-MH=37 (FIXED)
DRI-R-MH=32 (FIXED)
4 Maximum 1. Receive the "Monoscope Pattern" signal.
beam check 2. Press R/C to set Picture NORMAL condition.
3. Connect the DC miliammeter between TP603 (+)
and TP602 ().
(Full Scale: 3 mA Range)
4. Beam current must be within 990 ± 50 µA.
12
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MODEL 20AR21 CHASSIS LAYOUT
H
G
F
E
D
C
B
A
1 2 3 4 5 6
13
20AR21
20AR31
MODEL 20AR31 CHASSIS LAYOUT
H
G
F
E
D
C
B
A
1 2 3 4 5 6
14
20AR21
20AR31
BLOCK DIAGRAM-1
H
G
F
E
D
C
B
A
1 2 3 4 5 6
15
20AR21
20AR31
MODEL 20AR21 BLOCK DIAGRAM-2
H
G
F
E
D
C
B
A
1 2 3 4 5 6 7 8 9 10 11 12
16 17
20AR21
20AR31
MODEL 20AR31 BLOCK DIAGRAM-2
H
G
F
E
D
C
B
A
1 2 3 4 5 6 7 8 9 10 11 12
18 19
20AR21
20AR31
DESCRIPTION OF SCHEMATIC DIAGRAM
NOTES: WAVEFORM MEASUREMENT CONDITIONS:
1. The unit of resistance "ohm" is omitted. 1. Photographs taken on a standard gated color bar
(K=k=1000, M=M) signal, the tint setting adjusted for proper color. The
2. All resistors are 1/16 watt, unless otherwise noted. wave shapes at the red, green and blue cathodes of
3. All capacitors are µ F, unless otherwise noted. the picture tube depend on the tint, color level and
(P=pF=µµF) picture control.
4. (G) indicates ±2% tolerance may be used. 2. indicates waveform check points (See chart,
5. indicates line isolated ground. waveforms are measured from point indicated to
6. indicates hot ground. chassis ground.)
VOLTAGE MEASUREMENT CONDITIONS: å AND SHADED ( ) COMPONENTS
1. All DC voltages are measured with DVM connected = SAFETY RELATED PARTS.
between points indicated and chassis ground, line ' MARK= X-RAY RELATED PARTS.
voltage set at 120V AC and all controls set for normal
picture unless otherwise indicated. This circuit diagram is a standard one, printed circuits
2. All voltages measured with 1000µ V B & W or Color may be subject to change for product improvement
signal. without prior notice.
WAVEFORMS
1 1.0 Vp-p 2 2.8 Vp-p 3 2.6 Vp-p 4 2.7 Vp-p 5 65.0 Vp-p
Horiz. Rate Horiz. Rate Horiz. Rate Horiz. Rate Horiz. Rate
6 67.0 Vp-p 7 80.0 Vp-p 8 3.0 Vp-p 9 2.3 Vp-p 0 116.0 Vp-p
Horiz. Rate Horiz. Rate Vert. Rate Horiz. Rate Horiz. Rate
q 8.4 Vp-p w 40.8 Vp-p e 98.0 Vp-p r 1,160 Vp-p t 415.0 Vp-p
Horiz. Rate Vert. Rate Horiz. Rate Horiz. Rate Power Supply Rate
20
20AR21
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SCHEMATIC DIAGRAM: CRT Unit
H
G
F
(DUNTKA542WEA3)
E
D
C
B
A
1 2 3 4 5 6
21
20AR21
20AR31
MODEL 20AR21 SCHEMATIC DIAGRAM: MAIN Unit
H
(DUNTKA541WEA7)
G
F
E
D
C
B
A
1 2 3 4 5 6 7 8 9 10 11 12
22 23
20AR21
20AR31
MODEL 20AR31 SCHEMATIC DIAGRAM: MAIN Unit
H
(DUNTKA541WEA8)
G
F
E
D
C
B
A
1 2 3 4 5 6 7 8 9 10 11 12
24 25
20AR21
20AR31
MODEL 20AR31 SCHEMATIC DIAGRAM: MTS MODULE Unit
H
G
F
E
D
C
B
A
1 2 3 4 5 6 7 8 9 10 11 12
26 27
20AR21
20AR31
PRINTED WIRING BOARD ASSEMBLIES
H
G
F
E
D
C
B
PWB-A: MAIN Unit (Wiring Side)
A
1 2 3 4 5 6
28
20AR21
20AR31
H
G
F
E
D
C
B
PWB-A: MAIN Unit (Chip Parts Side)
A
1 2 3 4 5 6
29
20AR21
20AR31
H
G
F
E PWB-B: CRT Unit (Wiring Side)
D
C
B
A PWB-B: CRT Unit (Chip Parts Side)
1 2 3 4 5 6
30
20AR21
20AR31
H
G
F
E PWB-E: MTS MODULE Unit (Wiring Side)
D
C
B
A PWB-E: MTS MODULE Unit (Chip Parts Side)
1 2 3 4 5 6
31
20AR21
20AR31
PARTS LIST Toshiba Part No. Part No. Ref.No. Description
PWB-A: DUNTK541WEA7 (20AR21)
PARTS REPLACEMENT PWB-A: DUNTK541WEA8 (20AR31)
Replacement parts which have these special safety characteristics MAIN UNIT
identified in this manual; electrical components having such features
are identified by å and shaded areas in the Replacement Parts Lists TUNER
and Schematic Diagrams. The use of a substitute replacement part NOTE: THE PARTS HERE SHOWN ARE SUPPLIED AS AN
ASSEMBLY BUT NOT INDEPENDENTLY.
which does no have the same safety characteristic as the factory
å AD100657 VTUENV56D82-1 Tuner
recommended replacement parts shown in this service manual may
create shock, fire or other hazards.