toshiba 21ARF45 Service Manual

(DRAFT)

SERVICE MANUAL

21ARF45

COLOR TELEVISION

MODELS

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.

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CONTENTS

Page

» ELECTRICAL SPECIFICATIONS .........................................................................................................1

» IMPORTANT SERVICE SAFETY PRECAUTION .................................................................................2

» LOCATION OF USER'S CONTROL .....................................................................................................4

» INSTALLATION AND SERVICE INSTRUCTIONS ................................................................................5

» SERVICE MODE...................................................................................................................................6

» ADJUSTMENT METHOD .....................................................................................................................7

» CHASSIS LAYOUT .............................................................................................................................11

» BLOCK DIAGRAM ..............................................................................................................................12

» DESCRIPTION OF SCHEMATIC DIAGRAM......................................................................................17

» WAVEFORMS .....................................................................................................................................18

» SCHEMATIC DIAGRAMS ...................................................................................................................19

» PRINTED WIRING BOARD ASSEMBLIES ........................................................................................24

» REPLACEMENT PARTS LIST ............................................................................................................27

» PACKING OF THE SET ......................................................................................................................34

ELECTRICAL SPECIFICATIONS

POWER INPUT ..................................................... AC 120 V, 60 Hz

POWER RATING .................................................................... 90W

PICTURE SIZE .......................................... 1,239 cm2 (192sq inch)

CONVERGENCE ............................................................. Magnetic

SWEEP DEFLECTION .................................................... Magnetic

FOCUS ................................................................................. Uni-Bi

INTERMEDIATE FREQUENCIES

Picture IF Carrier Frequency ..................................... 45.75 MHz

Sound IF Carrier Frequency...................................... 41.25 MHz

Color Sub-Carrier Frequency .................................... 42.17 MHz

(Nominal)

AUDIO POWER

OUTPUT RATING ........................................2.5 W(RMS) x 2pcs

SPEAKER

SIZE ...................................................................5 x 12 cm, 2pcs

VOICE COIL IMPEDANCE ............................ 16 ohm at 400 Hz

ANTENNA INPUT IMPEDANCE

VHF/UHF .....................................................75 ohm Unbalanced

TUNING RANGES

VHF-Channels...............................................................2 thru 13

UHF-Channels ............................................................14 thru 69

CATV Channels ...........................................................1 thru 125

(EIA, Channel Plan U.S.A.)

Specifications are subject to change without prior notice.

TOSHIBA CORPORATION

This document has been published to be used for after sales service only. The contents are subject to change without notice.

IMPORTANT SERVICE SAFETY PRECAUTION

Service work should be performed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow:

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WARNING

1. For continued safety, no modification of any circuit should be attempted.

2. Disconnect AC power before servicing.

3. Semiconductor heat sinks are potential shock hazards when the chassis is operating.

4. The chassis in this receiver has two ground systems which are separated by insulating material. The nonisolated (hot) ground system is for the B+ voltage regulator circuit and the horizontal output circuit. The isolated ground system is for the low B+ DC voltages and the secondary circuit of the high voltage transformer. To prevent electrical shock use an isolation transformer between the line cord and power receptacle, when servicing this chassis.

CAUTION: FOR CONTINUED PROTECTION AGAINST A RISK OF FIRE, REPLACE

4A 125V

ONLY WITH SAME TYPE 4A125V FUSE.

SERVICING OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE

When servicing the high voltage system, remove the static charge by connecting a 10k ohm resistor in series with an insulated wire (such as a test probe) between the picture tube ground and the anode lead. (AC line cord should be disconnected from AC outlet.)

1. Picture tube in this receiver employs integral implosion protection.

2. Replace with tube of the same type number for continued safety.

3. Do not lift picture tube by the neck.

4. Handle the picture tube only when wearing shatterproof goggles and after discharging the high voltage anode completely.

X-RADIATION AND HIGH VOLTAGE LIMITS

1. Be sure all service personnel are aware of the procedures and instructions covering X-radiation. The only potential source of X-ray in current solid state TV receivers is the picture tube. However, the picture tube does not emit measurable X-Ray radiation, if the high voltage is as specified in the "High Voltage Check" instructions. It is only when high voltage is excessive that Xradiation is capable of penetrating the shell of the picture tube including the lead in the glass material. The important precaution is to keep the high voltage below the maximum level specified.

2. It is essential that servicemen have available at all times an accurate high voltage meter. The calibration of this meter should be checked periodically.

3. High voltage should always be kept at the rated value

−no higher. Operation at higher voltages may cause a failure of the picture tube or high voltage circuitry and;also, under certain conditions, may produce radiation in exceeding of desirable levels.

4. When the high voltage regulator is operating properly there is no possibility of an X-radiation problem. Every time a color chassis is serviced, the brightness should be tested while monitoring the high voltage with a meter to be certain that the high voltage does not exceed the specified value and that it is regulating correctly.

5. Do not use a picture tube other than that specified or make unrecommended circuit modifications to the high voltage circuitry.

6. When trouble shooting and taking test measurements on a receiver with excessive high voltage, avoid being unnecessarily close to the receiver. Do not operate the receiver longer than is necessary to locate the cause of excessive voltage.

1.5k ohm 10W

0.15

TEST PROBE

TO EXPOSED METAL PARTS

CONNECT TO KNOWN EARTH GROUND

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IMPORTANT SERVICE SAFETY PRECAUTION

(Continued)

BEFORE RETURNING THE RECEIVER

(Fire & Shock Hazard)

Before returning the receiver to the user, perform the following safety checks.

1. Inspect all lead dress to make certain that leads are not pinched or that hardware is not lodged between the chassis and other metal parts in the receiver.

2. Inspect all protective devices such as non-metallic control knobs, insulating materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacity networks, mechanical insulators, etc.

3. To be sure that no shock hazard exists, check for leakage current in the following manner.

• Plug the AC cord directly into a 120 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.

• Connect the resistor connection to all exposed metal parts having a return to the chassis (antenna, metal cabinet, screw heads, knobs and control shafts, escutcheon, etc.) and measure the AC voltage drop across the resistor. AII checks must be repeated with the AC line cord plug connection reversed. (If necessary, a nonpolarized adapter plug must be used only for the purpose of completing these check.) Any current measured must not exceed 0.5 milliamp. Any measurements not within the limits outlined above indicate of a potential shock hazard and corrective action must be taken before returning the instrument to the customer.

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SAFETY NOTICE

Many electrical and mechanical parts in television receivers have special safety-related characteristics. These characteristics are often not evident from visual inspection, nor can protection afforded by them be necessarily increased by using replacement components rated for higher voltage, wattage, etc. 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.

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For continued protection, replacement parts must be identical to those used in the original circuit. The use of substitute replacement parts which do not have the same safety characteristics as the factory recommended replacement parts shown in this service manual, may create shock, fire, X-radiation or other hazards.

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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

The receiver is protected by a 4.0A fuse (F701), mounted on PWB-A, wired into one side of the AC line input.

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 120V 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 P603 Pin3 and make sure that the voltmeter reads 18.9 ±1.1V.

5. Apply external 24.5V DC at P603 Pin3 by using an external DC supply, TV must be shut off.

6. To reset the protector, unplug the AC cord at least 4 second before plugging in again. 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.

HIGH VOLTAGE CHECK

High voltage is not adjustable but must be checked to verify that the receiver is operating within safe and efficient design limitations as specified checks should be as follows:

1. Connect an accurate high voltage meter between ground and anode of picture tube.

2. Operate receiver for at least 15 minutes at 120V AC line voltage, with a strong air signal or a properly tuned in test signal.

3. Enter the service mode and set Y-mute ON by using Service R/C.

4. The voltage should be approximately 28.6kV (at zero beam). If a correct reading cannot be obtained, check circuitry for malfunctioning components. After the voltage test, make Y-mute off to the normal mode.

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Service Mode Overview

1. Service mode is entered by SERVICE key input or CH-UP +VOL-DOWN input during reset.

2. Service mode is cleared by entering SERVICE key or CH-UP +VOL-DOWN key command during service mode.

3. If key input port (SERVICE) input is LOW, then it is in service mode.

4. During key input port (SERVICE) input is LOW, clearing service mode by key input SERVICE or CH-UP + VOL-

5. Service mode can be switched to 4 modes as follows by key input MENU;

SERVICE MODE

DOWN is disabled.

Option mode

Adjustment mode

Setting mode

Check mode

6. AFT processing is disabled during service mode. PLL setting data is set to fo data.

7. All user data are set to default during service mode. FAO and SPEAKER user settings are off and on respectively in service mode. Energy Save is off.

8. Sleep timer, View timer and Off timer are inactivated in Service mode.

9. Sound is muting in service mode except at Adjustment Items V20, M01, M02, M03, M04, M05, and M06.

First mode of service mode when SERVICE key is pressed.

First mode of service mode when local key CH-UP + VOL-DOWN is pressed after MCU reset.

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Adjustment Mode Items

Caution: to get into the service mode, one of the ways is press direct key for service items. the other ways

is short the main chassis JA309 and JA402

There is three stage of Service Mode data

First stage data from V01 ~ M06 to go into second stage of service mode data, press MENU key Second stage data from F01 ~ F51 to go into third stage of service mode data, press MENU key Third stage data from 001 ~ 020

Below is the contents of these data

First Stage

No. Item Name IC Register Range Default

V01 SUB-PICTURE 1 Chip CONTRAST 0~127 127

V02 SUB-TINT 1 Chip TINT 0~127 64

V03 SUB-COLOR 1 Chip COLOR 0~127 64

V04 SUB-BRIGHT 1 Chip BRIGHT 0~255 128

V05 SUB-SHARP 1 Chip VIDEO-TONE 0~63 32

V06 V-SHIFT 1 Chip V-SHIFT 0~7 4

V07 H-SHIFT 1 Chip H-PHASE 0~31 16

V08 RF-AGC 1 Chip RF-Delay 0~127 127

V09 V-SIZE 1 Chip V-SIZE 0~63 32

V10 PIF-VCO 1 Chip VIF-VCO 0~63 32

V11 R-CUTOFF 1 Chip R-CUTOFF 0~255 127

V12 G-CUTOFF 1 Chip G-CUTOFF 0~255 127

V13 B-CUTOFF 1 Chip B-CUTOFF 0~255 127

V14 R-DRIVE 1 Chip R-DRIVE 0~127 64

V15 B-DRIVE 1 Chip B-DRIVE 0~127 64

V16 SUB-COLOR(YUV) 1 Chip COLOR 0~127 64

V17 SUB-TINT(YUV) 1 Chip BASEBAND-TINT 0~127 64

V18 CC-POS Micron 0~255 32

V19 (Vertical mode) 1 Chip V-MUTE,SERVICE 0, 1, 2 0

V20 SUB-VOL 1 Chip A-ATT 0~127 127

V21 H-VCO 1 Chip H-VCO 0~7 4

M01 MTS-ATT MTS ATT 0~15 10

M02 MTS-VCO MTS VCO 0~63 32

M03 MTS-FILTER MTS FILTER 0~63 28

M04 MTS-WIDEBAND MTS WIDEBAND 0~63 27

M05 MTS-SPECTRAL MTS SPECTRAL 0~63 32

M06 SUB-VOL MTS VOL 0~63 63

ADJUSTMENT METHOD

Auto Adjustment Item

1. H-VCO (Currently need manual adj)

2. RF-AGC

3. PIF-VCO

4. MTS-FILTER

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SELF ADJUSTMENT

H-VCO

1. When there is H-VCO self-adjustment key input for adjustment item H-VCO, self-adjustment is performed.

2. H-FREE(1chip) is set to 1.

3. H-OUT is set by intelligent monitor output.

4. IM input is set as TIM input.

5. H-VCO(1chip) data is changed so that the number of input pulse is 125 inside 8ms interval.

6. When adjustment completed, OSD display and H-VCO self-adjustment status data of EEPROM are updated.

7. H-FREE(1chip), intelligent monitor output and IM input mode are recovered.

RF-AGC

1. When there is RF-AGC self-adjustment key input for adjustment item RF-AGC, self-adjustment is performed.

2. AGC-OUT is set by intelligent monitor output.

3. IM input is set as AD input.

4. By decreasing RF-AGC (1chip) data from current RF-AGC adjustment value to 0, AFT input voltage becomes the maximum setting value.

5. Increase RF-AGC(1chip) data, when AFT input voltage is at (max. 0.3V) point, adjustment is completed.

6. When adjustment completed, OSD display and RF-AGC self-adjustment status data of EEPROM are updated.

7. Intelligent monitor output and IM input mode are recovered.

PIF-VCO

1. When there is PIF-VCO self-adjustment key input for adjustment item PIF-VCO, self-adjustment is performed.

2. VIF-DEF(1chip) is set to 1.

3. AFC is set by intelligent monitor output.

4. IM input is set as AD input.

5. VIF-VCO(1chip) data is changed so that input voltage becomes 2.5V.

6. When adjustment completed, OSD display and PIF-VCO self-adjustment status data of EEPROM are updated.

7. VIF-DEF(1chip), intelligent monitor output and IM input mode are recovered.

MTS-FILTER

Adjustment is performed in the center of the range when FILTER status is OK.

1. If data is changed from 0 to 63, point where NG → OK is A and point where OK → NG is B.

2. If data is changed from 63 to 0, point where NG → OK is C and point where OK → NG is D.

3. (A+B+C+D)/4 is the adjustment point.

Setting Mode Items

Second Stage

No. Item Name IC Register Range Default

F01 VideoTone-Gain (TV) 1chip V-TONE 0 / 1 0 F02 VideoTone-Gain (AV) 1chip V-TONE 0 / 1 0 F03 VideoTone-Gain(YUV) 1chip V-TONE 0 / 1 0 F04 ABCL 1chip ABCL 0 / 1 0 F05 BS 1chip BS-OFF 0 / 1 0 F06 ABCL-G 1chip ABCL-G 0 / 1 0 F07 SHP-AV OFFSET VIDEO-TONE(OFFSET) -16~+16 0 F08 SHP-YUV OFFSET VIDEO-TONE(OFFSET) -16~+16 0 F09 RGB-CLIP 1chip ExtRGB-Clip 0 / 1 0 F10 E-SAVE OFFSET CONTRAST(OFFSET) 0~63 30 F11 FAO-VOL 1chip A-ATT 0~127 120 F12 PIF-G 1chip VIF-GAIN 0~7 4 F13 Y-DELAY(TV) 1chip Y-Delay 0~7 0 F14 Y-DELAY(AV) 1chip Y-Delay 0~7 0 F15 Y-DELAY(YUV) 1chip Y-Delay 0~7 0 F16 TINT-AV OFFSET TINT(OFFSET) -32~+32 0 F17 COL-AV OFFSET COLOR(OFFSET) -32~+32 0 F18 R-DRI(R2) OFFSET R-DRI(OFFSET) -32~+32 0 F19 R-DRI(R) OFFSET R-DRI(OFFSET) -32~+32 0 F20 R-DRI(B) OFFSET R-DRI(OFFSET) -32 ~+32 0 F21 B-DRI(R2) OFFSET B-DRI(OFFSET) -32~+32 0 F22 B-DRI(R) OFFSET B-DRI(OFFSET) -32~+32 0 F23 B-DRI(B) OFFSET B-DRI(OFFSET) -32~+32 0 F24 V-FREE 1chip V-FREE 0 / 1 0 F25 GAMMA 1chip GAMMA 0~3 0 F26 TRAP(TV) 1chip TRAP-FINE 0~3 2 F27 TRAP(AV) 1chip TRAP-FINE 0~3 2 F28 H-FREE 1chip H-FREE 0 / 1 0 F29 1W(TV) 1chip V.Window 0 / 1 0 F30 1W(AV) 1chip V.Window 0 / 1 0 F31 YLPF 1chip YSW-LPF 0 / 1 1 F32 BS-D 1chip BS-DISCHARGE 0~3 0 F33 BS-C 1chip BS-CHARGE 0~3 0 F34 SL(TV) 1chip S-SLICE DOWN 0~3 0 F35 SL(AV) 1chip S-SLICE DOWN 0~3 0 F36 SL(YUV) 1chip S-SLICE DOWN 0~3 0 F37 AFC2 1chip AFC2-G 0 / 1 0 F38 VD(TV) 1chip Vsync-Det 0 / 1 0 F39 VD(AV) 1chip Vsync-Det 0 / 1 0 F40 AS(TV) 1chip Auto-Slice 0 / 1 0 F41 AS(AV) 1chip Auto-Slice 0 / 1 0 F42 AS(YUV) 1chip Auto-Slice 0 / 1 0 F43 FBP(TV) 1chip FBP Vth 0 / 1 0 F44 FBP(AV) 1chip FBP Vth 0 / 1 0 F45 FBP(YUV) 1chip FBP Vth 0 / 1 0 F46 C.Clip Level 1chip C.Clip Level 0 / 1 0 F47 PSW MTS PSW 0 / 1 0 F48 FAO-VOL MTS VOL 0~63 60 F49 CP PLL CP 0 / 1 0 F50 CC LEVEL MICRON 0 F51 OSD POS MICRON 0 F52 OFFSET-ADJ-COL 1 chip COLOR -32~32 0 F53 OFFSET-ADJ-TINT 1 chip TINT -32~32 0 F54 OFFSET-ADJ-TINT-YUV 1 chip BASEBAND-TINT -32~32 0

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Option Mode Items

Third Stage

No ITEM 0 1 DEFAULT O01 DEM0 Without DEMO With DEMO 1 O02 DOWNLOAD Without V-CHIP OP With V-CHIP OP 1 O03 V-CHIP Without V-CHIP With V-CHIP 1 O04 SPEAKER Without SPEAKER With SPEAKER 1 O05 FAO Without FAO With FAO 1 O06 P.PREF Without P.PREF With P.PREF 1 O07 UNIV+ Without UNIV+ With INIV+ 1 O08 VIEW TIMER Without VIEW TIMER With VIEW TIMER 1 O09 EZ-SETUP EZ-SETUP AUTO PRESET 1 O10 PON-CH Without POWER-ON With POWER-ON 1 O11 FAV-COL FAV-COL COL-TEMP 1 O12 COMPONENT Without COMPONENT With COMPONENT 1 O13 AV Without AV With AV 1 O14 AV2 AV1 system AV2 system 1 O15 MTS Without MTS With MTS 1 O16 TONE-CTRL Without S-ADJ With S-ADJ 1 O17 AUTO-OFF Without AUTO-OFF With AUTO-OFF 1 O18 INIT-LANG ENGLISH SPANISH 1 O19 SETUP-FLAG NO SETUP AUTO SETUP 1

3: Display "FRONT A/V INPUTS" and "REAR A/V INPUTS" in DEMO mode.

O20 FR.AV (Front, 3

Rear AV)

2: Display "FRONT A/V INPUTS" only in DEMO mode. 1: Display "REAR A/V INPUTS" only in DEMO mode. 0: No display of above lines in DEMO mode.

Check Mode

Micron mask version, software version and ROM correction function status are displayed in check mode.

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