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Toshiba 21E88 Service Manual

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SERVICE MANUAL

FILE NO. SM-CTV-O-081
COLOR TELEVISION
SERVICE MANUAL
MODELNO. 21E88
CHASSIS NO. CN-18EA
Please read this manual carefully before service.

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  Summary of Contents for Toshiba 21E88

  • Page 1: Service Manual

    SERVICE MANUAL FILE NO. SM-CTV-O-081 COLOR TELEVISION SERVICE MANUAL MODELNO. 21E88 CHASSIS NO. CN-18EA Please read this manual carefully before service.
  • Page 2: Table Of Contents

    SERVICE MANUAL TABLE OF CONTENTS SPECIFICATIONS ......................1 SAFETY INSTRUCTIONS AND MAINTENANCE ........2 X-RAY RADIATION PRECAUTION ..................2 SAFETY PRECAUTION ......................2 PRODUCT SAFETY NOTICE ....................3 SAFETY SYMBOL DESCRIPTION ..................4 MAINTENANCE ........................4 ADJUSTMENTS ........................ 5 SET-UP ADJUSTMENTS......................5 CIRCUIT ADJUSTMENTS ......................
  • Page 3: Specifications

    SERVICE MANUAL SPECIFICATIONS Model Number 21E88 Color system PAL, NTSC3.58, NTSC4.43 RF system Sound system B/G, M, D/K, I Video system PAL4.43, NTSC3.58, NTSC4.43 (50/60Hz) Programs preset 236 (0-235) Antenna input 75¦¸ (unbalanced) Picture tube Effective screen dimensions 406¡Á 305mm (Approx.)
  • Page 4: Safety Instructions And Maintenance

    SERVICE MANUAL SAFETY INSTRUCTIONS AND MAINTENANCE ¡ ° WARNING: BEFORE SERVICING THIS CHASSIS, READ THE X-RAY RADIATION ¡ ± ¡ ° ¡ ± ¡ ° ¡ ± PRECAUTION SAFETY PRECAUTION PRODUCT SAFETY NOTICE INSTRUCTION BELOW. X-RAY RADIATION PRECAUTION 1. The EHT must be checked every time the TV is serviced to ensure that the CRT does not emit X-ray radiation as result of excessive EHT voltage.
  • Page 5: Product Safety Notice

    SERVICE MANUAL 4. When replacing ICs, use specific tools or a static-proof electric iron with small power (below 35W). 5. Do not use a magnetized screwdriver when tightening or loosing the deflection yoke assembly to avoid electronic gun magnetized and decrement in convergence of the CRT. 6.
  • Page 6: Safety Symbol Description

    SERVICE MANUAL SAFETY SYMBOL DESCRIPTION The lightning symbol in the triangle tells you that the voltage inside this product may be strong enough to cause an electric shock. Extreme caution should be exercised when working on the TV with the back removed. This is an international hazard symbol, telling you that the components identified by the symbol have special safety-related characteristics.
  • Page 7: Adjustments

    SERVICE MANUAL ADJUSTMENTS SET-UP ADJUSTMENTS The following adjustments should be made when a complete realignment is required or a new picture tube is installed. Perform the adjustments in the following order: 1. Color purity 2. Convergence 3. White balance Notes: The purity/convergence magnet assembly and rubber wedges need mechanical positioning.
  • Page 8 SERVICE MANUAL Fig. 1 2. Convergence Adjustment Preparation: Before attempting any convergence adjustment, the TV should be operated for at least 15 minutes. 2.1 Center convergence adjustment 2.1.1 Receive dot pattern. 2.1.2 Adjust the brightness/contrast controls to obtain a sharp picture. 2.1.3 Adjust two tabs of the 4-pole magnet to change the angle between them and red and blue vertical lines are superimposed each other on the center of the screen.
  • Page 9 SERVICE MANUAL deflection yoke assembly on the picture tube. 2.2.6 Detach the temporarily mounted wedge and put it in either upper space. Fasten the deflection yoke assembly on the picture tube. 2.2.7 After fastening the three wedges, recheck overall convergence and ensure to get optimal convergence.
  • Page 10: Circuit Adjustments

    SERVICE MANUAL CIRCUIT ADJUSTMENTS Preparation: Circuit adjustments should be made only after completion of set-up adjustments. Circuit adjustments can be performed using the adjustable components inside the TV set. For TVs with C bus control, first change the bus data. 1.
  • Page 11 SERVICE MANUAL 3. High Voltage Inspection Measure voltages of test points on the main PCB with the digital voltmeter. Measure the CRT high voltage with the high-voltage testing equipment and heater voltage with the high-frequency effective voltmeter. The rated values are shown as below. Table 2 Test Point Voltage (V)
  • Page 12 SERVICE MANUAL 5.2 Requirements for insulation resistance Measure resistance between naked metal of the TV and feed end of the power cord to be infinity with a DC-500 high resistance meter and insulation resistance between the naked metal and degaussing coil to be over 20M¦¸ . 6.
  • Page 13 SERVICE MANUAL 0: No 1: Yes Bit7 Write-in LOGO 0: No 1: Yes Bit6 NICAM DK for CHINA With two sets of AV terminals, Bit5 0£º Yes (Recommended) 1£º No refresh AV terminals ? 0: No 1: Yes Bit4 Screen saver MODE1 Bit3 0: No...
  • Page 14 SERVICE MANUAL Option bit for default language by BIT 3 0: Chinese 1: English AUTO button and initialization BIT 2 PWM output option 0: No 1: Yes BIT 1 Instant on 1: Yes 0£º No AV Switch 4053 option 0: No 1: Yes BIT 0 Audio processing IC (SOUND...
  • Page 15 SERVICE MANUAL Bit 2 Y-MUTE 0: No 1: Yes Bit 1 No use Bit 0 No use Horizontal position of OSD RCUT R cut off GCUT G cut off BCUT B cut off GDRV G drive BDRV B drive CNTX Contrast Max.
  • Page 16 SERVICE MANUAL COLN Color Min. TNTX Tint Max. TNTN Tint Min. Sharp center for NTSC 3.58 (TV) Sharp center for NTSC 3.58 (VIDEO) Sharp center for other color system (TV) Sharp center for other color system (VIDEO) Sub sharp center in DVD ASSH Asymmetry sharpness SHPX...
  • Page 17 SERVICE MANUAL 00: Off 01: Black stretch point, 25 IRE Bit 1.0 Black stretch 10: 35IRE 11: 45IRE CLTO Bit 7 Killer off 0: Normal 1: Always killer off Chroma 0: PAL/ NTSC killer sensitivity, 1mVpp Bit 6 P/N ID data 1: 10mVpp (TV&not...
  • Page 18 SERVICE MANUAL Adjusting difference between vertical linear in PAL and NTSC VLIS Shift data of 50 Hz/ 60 Hz Correction No use DPCS No use HIT69 Vertical amplitude in 16:9 mode (PAL) DPC69 No use Vertical amplitude in 16:9 mode (NTSC) HIT69S DPC69S No use...
  • Page 19 SERVICE MANUAL Data Description Blanking Period Picture Period AFC gain BIT 3.2 (in VIDEO mode) HAFC Data Description Blanking Period Picture Period AFC gain BIT 1.0 (in TV mode) Volume output data at 1% Volume output data at 25% Volume output data at 50% V100 Volume output data at 100% Woofer...
  • Page 20 SERVICE MANUAL RSNS R sense 00: x 0 20: x 0.5 3F: x 1.0 GSNS G sense 00: x 0 20: x 0.5 3F: x 1.0 BSNS B sense 00: x 0 20: x 0.5 3F: x 1.0 001: 45.75 MHz 011: 38.9 MHz PIF frequency 6.5.4...
  • Page 21 SERVICE MANUAL VTST No use PYNX Normal H.SYNC Max. 0-----------3F PYNN Normal H.SYNC Min. 0-----------3F PYXS ASM/search H.SYNC Max. 0-----------3F PYNS ASM/search H.SYNC Min. 0-----------3F BASC Bass volume center BASX Bass volume Max. TREC Treble volume center BALC Balance volume center BASS IN MUSIC MODE SET BAS1 TRE1...
  • Page 22 SERVICE MANUAL NICH MONO->NICAM level (No use in simple version) AFC gain data setting in TV mode: 1: Adjust HAFC gain in the lowest two bits of HAFC Bit 2 0: With weak signal received, AFC gain = 0x10; with strong signal received, AFC gain = 0x00 NOIS Criterion of signal strength: >NOIS: Weak signal...
  • Page 23 SERVICE MANUAL (No use in simple version) MDB6C MDB high pass corner 2 20 Hz frequency 3 30Hz (0x07) 30 300 Hz (No use in simple version) MDB6B MDB low pass corner 5 50 Hz frequency 6 60Hz (0x08) 30 300 Hz (No use in simple version) Mdb2dh Subwoofer...
  • Page 24 SERVICE MANUAL EQU11 CNTN BASX EQU12 BRTX VLIS TREC EQU13 BRTN BALC EQU14 COLX HIT69 BAS1 EQU15 COLN HIT69S BAS2 EQU21 TNTX BAS3 EQU22 TNTN TRE1 EQU23 BRTS TRE2 EQU24 RAGC TRE3 EQU25 HAFC WFL1 EQU31 WFL2 EQU32 WFL3 EQU33 ASSH WON1 EQU34...
  • Page 25: Control Buttons

    SERVICE MANUAL CONTROL BUTTONS 1. CONTROL BUTTONS Fig. 5 Front panel Fig. 6 Rear panel...
  • Page 26: Remote Control

    SERVICE MANUAL 2. REMOTE CONTROL Fig. 7 Remote control Notes: (1) When in operation ¡¡ please point your remote control directly to the infrared sensor. (2) Do not expose the remote control to impacts ¡¡ water or disassemble it. (3) Do not repeatedly press the buttons on the remote control. Allow interval of no less than two seconds.
  • Page 27: Basic Functions

    SERVICE MANUAL 3. BASIC FUNCTIONS Power On/Off 1. Memory power on Plug in the supply socket and press the MAIN POWER SWITCH on the TV. The TV enters the former mode before Power-off ¡¡ i.e. the TV directly enters the TURN ON mode if in the TURN ON mode before power-off, or enters the STANDBY mode if in the STANDBY mode before power-off.
  • Page 28 SERVICE MANUAL 3. On-screen display Press the DISPLAY button repeatedly in the TV or AV mode to display the current information on the screen and turn off the display respectively. With other OSD, pressing the DISPLAY button first can turn it off. 4.
  • Page 29 SERVICE MANUAL Tuning in This section gives descriptions about adjustment of items in the TUNING menu. 1. Auto search After selecting “ASM” in the TUNING menu, press the VOL+ button. The TV will search automatically in sequence. After auto search, the TV will store receivable channels and returns to CH NO.
  • Page 30: Structure And Chassis Function Description

    SERVICE MANUAL STRUCTURE AND CHASSIS FUNCTION 1. STRUCTURE BLOCK DIAGRAM...
  • Page 31: Block Diagram For Supply Voltage System

    SERVICE MANUAL 2. BLOCK DIAGRAM FOR SUPPLY VOLTAGE SYSTEM...
  • Page 32: Chassis Description

    3. CHASSIS DESCRIPTION General Description CN-18EA chassis is applied in 21E88 series. By use of Toshiba V/C/D-MCU 2IN1 IC for TV small signal processing and bus control, the chassis enables TV tuning, adjustment, control and picture correction, featuring high-integration, high-performance-to-price ratio and high-reliability and compact circuit with fewer external components.
  • Page 33: Service Data

    SERVICE DATA TECHNICAL DATA OF KEY ICS 1. TOSHIBA 2IN1 IC SERIES 1) General Description Toshiba 2IN1 IC series are super ICs combined small signal processing with 8-bit micro control unit, including TMPA8801/8802/8803/8807/8808/8809/8812/8813/8821/8823/ 8827/8829 with the following features. Table 6...
  • Page 34 SERVICE MANUAL TMPA8801/8807CMBNG /CPBNG/CRBNG /CSBNG MCU AND SIGNAL PROCESSOR FOR A PAL/NTSC/SECAM TV The TMPA8801/8807CMBNG /CPBNG /CRBNG /CSBNG is an integrated circuit for a PAL/NTSC/SECAM TV. A MCU and a TV signal processor are integrated in a 64-pin shrink DIP package. The MCU contains 8-bit CPU, ROM, RAM, I/O ports, timer/counters, A/D converters, an on-screen display controller, remote control interfaces, IIC bus interfaces and the Closed...
  • Page 35 SERVICE MANUAL 2). Features  H igh speed 8-bit CPU (TLCS-870/X series) CCD Decoder  I nstruction execution time: 0.5 ¡¡ s (at 8 MHz)  D igital data slicer for NTSC  ( TMPA8801/8807CMBNG) 32-Kbytes ROM, 2-Kbytes RAM  C lock generation for OSD display (TMPA8801/8807CPBNG) ...
  • Page 36 SERVICE MANUAL 3). Block Diagram for TMPA8801 Fig. 13...
  • Page 37 SERVICE MANUAL 4). Block Diagram for TMPA8807 Fig. 14...
  • Page 38 SERVICE MANUAL 5). Basic Structure 5.1). Internal Connections TMPA8801/8807 has two pieces of IC chip in one package, using Multi-Chip-Package (MCP) technology. One is a micro controller (MCU) and the other one is a signal processor (SP) for a color TV. There are some internal connections between these two ICs for handling below signals.
  • Page 39 SERVICE MANUAL of functions work properly, so that designing the oscillation frequency accurately is required. The spec crystal is recommended to be within fosc: 8 MHz +/-20 ppm ftemp: 8 MHz +/-40 ppm (-20°C to +65°C) While RESET of MCU is active, the MCU function stops. Hardware and software initialization sequence including power supplies control is required, because status of any hardware after the RESET period is unknown especially horizontal oscillator which is a very basic timing generator of SP operation.
  • Page 40 SERVICE MANUAL uP AVDD Power VDD for OSD Oscillator circuit Supply Supply 5 V P52/SDA (SDA) (I/O) IIC bus serial data input/output P51/SCL (SCL) (I/O) IIC bus serial clock input/output P50/PWM 7 bit/TC2/ Int0 (/PWM8) (output) 7-bit D/A conversion (PWM) output (TC2) (input) Timer/Counter input...
  • Page 41 SERVICE MANUAL Terminal to be connected capacitor to generate V saw signal. V saw V saw amplitude is kept constant by V AGC function. V OUT Output terminal for Vertical driving pulse. H.VCC 9 V VCC terminal for DEF circuit. Supply 9 V. -(For TMPA8801) Connect to GND via resister Terminal for switching of PIP mode...
  • Page 42 SERVICE MANUAL IF VCC 5 V VCC terminal for IF circuit. Supply 5 V. S-Reg.F Terminal to be connected capacitor for stabilizing internal bias. Deemph/ Terminal to be connected capacitor for SIF Det Audio out De-Emphasis. IF AGC Terminal to be connected with IF AGC filter.
  • Page 43 SERVICE MANUAL 7). Microcontrollers Descriptions (MROM version: TMPA8801/8807CMBNG /CPBNG /CRBNG /CSBNG) Fig. 15...
  • Page 44 SERVICE MANUAL 2. AUDIO POWER AMPLIFIER TDA8943SF/TDA8944J 6 W MONO BRIDGE TIED LOAD (BTL) AUDIO AMPLIFIER 1). General description The TDA8943SF is a single-channel audio power amplifier with an output power of 6 W at an 8 Ω load and a 12 V supply. The circuit contains a Bridge Tied Load (BTL) amplifier with an all-NPN output stage and standby/mute logic.
  • Page 45 SERVICE MANUAL 4.1) Pinning Fig 17. Pin configuration. 4.2) Pin description Table 10 Pin description Description Symbol OUT− negative loudspeaker terminal supply voltage OUT+ positive loudspeaker terminal positive input IN− negative input half supply voltage decoupling (ripple rejection) MODE mode selection input (standby, mute, operating) ground n.c.
  • Page 46 SERVICE MANUAL 3. TDA8944J 2 X 7 W STEREO BRIDGE TIED LOAD (BTL) AUDIO AMPLIFIER 1). General descriptio n The TDA8944J is a dual-channel audio power amplifier with an output power of 2 × 7 W at an 8 Ω load and a 12 V supply. The circuit contains two Bridge Tied Load (BTL) amplifiers with an all-NPN output stage and standby/mute logic.
  • Page 47 SERVICE MANUAL 4). Pinning information 4.1) Pinning Fig 19. Pin configuration. 4.2) Pin description Table 11 Pin description Symbol Description OUT1− negative loudspeaker terminal 1 GND1 ground channel 1 supply voltage channel 1 OUT1+ positive loudspeaker terminal 1 n.c. not connected IN1+ positive input 1 n.c.
  • Page 48 SERVICE MANUAL half supply voltage decoupling (ripple rejection) IN2+ positive input 2 n.c. not connected OUT2− negative loudspeaker terminal 2 GND2 ground channel 2 supply voltage channel 2 OUT2+ positive loudspeaker terminal 2 TDA8944J: Stereo power amplifier, Max output power: 2¡Á 7W...
  • Page 49 SERVICE MANUAL 4. VERTICAL SCAN OUTPUT STAGE CIRCUIT LA78040/LA78041 Both LA78040/LA78041 are vertical scan output stage power amplifiers. But there is a little bit difference between the two amplifiers, that is, LA78040 has supply voltage of 24V and output current of 1.8A while LA78041 has supply voltage of 30V and output current of 2.2A LA78040 /LA78041...
  • Page 50 SERVICE MANUAL 5. TDA9808T SINGLE STANDARD VIF-PLL WITH QSS-IF AND FM-PLL DEMODULATOR 1). Features 2). General Description ·5V supply voltage (9V supply voltage for The TDA9808T is an integrated circuit for TDA9808T (DIP20) only) single standard (negative modulated) vision ·Applicable for IFs (lntermediate Frequencies) of IF signal processing and FM demodulation, 38.9MHz, 45.75MHz and 58.75 MHz with single reference QSS-IF in TV and VTR...
  • Page 51 SERVICE MANUAL 3).Block Diagram...
  • Page 52 SERVICE MANUAL 6. MSP34X0G MULTISTANDARD SOUND PROCESSOR FAMILY Release Note: Revision bars indicate significant Other processed standards are the Japanese changes to the previous edition. The hardware FM-FM multiplex standard (EIA-J) and the and software description in this document is FM Stereo Radio standard.
  • Page 53 SERVICE MANUAL 7. EEPROM AT24C04/08/16 1) Features Low-voltage and Standard-voltage Operation -2.7 (Vcc=2.7V to 5.5V) -1.8 (Vcc=1.8V to 5.5V) Internally Organized 128x8(1K), 256x8 (2K), 512x8 (4K), 1024x8 (8K) or 2048x8 (16K) 2-wire Serial Interface Schmitt Trigger, Filtered Inputs for Noise Suppression Bi-directional Data Transfer Protocol 100kHz (1.8V, 2.5V, 2.7V) and 400 kHz (5V) Compatibility Write Protect Pin for Hardware Data Protection...
  • Page 54 SERVICE MANUAL 3) Pin Configuration 8-lead TSSOP Table 12 8-lead MAP Pin Name Function A0-A2 Address Inputs Serial Data Serial Clock Input Write Protect No Connect Bottom View Fig. 24 8-pin PDIP 8-lead SOIC Fig.25 4) Pin Description SERIAL CLOCK (SCL): The SCL input is used to positive edge clock data into each EEPROM device and negative edge clock data out of each device.
  • Page 55 SERVICE MANUAL protection. The Write Protect pin allows normal read/write operations when connected to ground (GND). When the Write Protect pin is connected to Vcc, the write protection feature is enabled and operates as shown in table 13. Table 13 WP Pin Part of the Array Protected Status...
  • Page 56 SERVICE MANUAL 8. SWITCH-MODE POWER SUPPLY IC STRG5653/G8656 1). General Description The STRG5653/G8656 are part of the STRG5600/G8600 series thick-film ICs for switch-mode power supply incorporating power MOSFET with a high-precise error amplifier. The ICs feature fewer external components, small-size and standard power supply. The series STR-G8600 use Chip on Chip technology with the same operation principle as STR-G5600.
  • Page 57: Service Data Of Key Ics

    SERVICE MANUAL SERVICE DATA OF KEY ICS Table 14 Functions and Service Data of AT24C08/16 Pins Digital Multimeter Pin No. Function Description Reference Voltage Positive Resistance Negative Resistance (20KΩ) (20KΩ) Address input 0.001 0.00 Address input 0.001 0.00 Address input 0.001 0.00 Common ground...
  • Page 58 SERVICE MANUAL DVSVP 4.79 4.54 DVSS 0.01 0.001 0.00 I2S-DA-IN2 0.07 5.31 ∞ ∞ RESETQ 4.76 5.24 DACA-R 3.54 DACA-L 0.08 3.52 VREF-I 0.01 0.001 0.00 DACM-R 0.17 3.52 DACM-L 0.08 3.54 DACM-SVB 0.18 SC2-OUT-R 3.82 5.92 SC2-OUT-L 3.82 5.91 CREF 1 0.01 0.001...
  • Page 59 SERVICE MANUAL ANA-IN1- 1.53 5.26 ANA-IN2+ 0.09 5.27 TESTEN 0.01 0.001 0.00 XTAL-2N 2.35 5.27 XTAL-OUT 2.36Hs Table 16 Functions and Service Data of TDA9808T Pins Digital Multimeter Pin No. Function Description Reference Positive Negative Voltage (V) Resistance (20KΩ) Resistance(20KΩ) PIF signal input 1 3.23 6.03...
  • Page 60 SERVICE MANUAL Table 17 Ground Resistance of TMPA8801PSBNG Pins Pin No 31.70K¦¸ 31.70 K¦¸ 42.87 K¦¸ 5.5 K¦¸ 44.25 K¦¸ Resistance Pin No 44.31 K¦¸ 17.56 K¦¸ 39.79 K¦¸ Resistance Pin No 0.66 K¦¸ 39.81 K¦¸ 39.85 K¦¸ 10.55 K¦¸ 12.76 K¦¸...
  • Page 61 SERVICE MANUAL Table 18 Operating Voltage of TMPA8801PSBNG (N201)’s Pins 5.2V 2.3V 2.3V 1.6V 4.2V 4.8V 8.4V 2.0V 2.4V 2.4V 2.4V 2.3V 3.4V 2.4V 4.8V 3.5V 1.8V 4.4V 2.8V 2.2V 2.5V 2.2V 4.4V 4.2V 1.7V 1.7V 4.2V 1.2V 1.8V 2.5V 2.5V 2.5V 2.5V...
  • Page 62: Replacement Of Parts

    SERVICE MANUAL REPLACEMENT OF PARTS 1. DESCRIPTION Many electrical and mechanical components in this chassis have special safety-related characteristics. Components which have these special safety characteristics in this manual and its supplements are identified by the international hazard symbols or UL, FCC, FDA or VDE marking on the circuit diagram and parts list.
  • Page 63 CIRCUIT DIAGRAM FOR 21E88...
  • Page 64 Final Assembly Diagram for 21E88 or or White nitro magnetic paint Q04-3 White nitro magnetic paint Q04-3 Soldering agent Soldering agent Tin solder Tin solder Plasticine Plasticine Protection film 2124 - width=250mm Protection film 2124 - width=250mm Binding wire XJ-100...
  • Page 65 FINAL WIRING DIAGRAM FOR 21E88 Side AV Board Assembly Side AV Board Assembly XPK03B XPK03B XPK04B XPK04B Wired Connector XPK03 Wired Connector XPK03 From Wire Connector XS10A of Front Cover Assembly From Wire Connector XS10A of Front Cover Assembly Main Board Assembly...
  • Page 66 PRINTED CIRCUIT BOARD DIAGRAM (1)
  • Page 67 PRINTED CIRCUIT BOARD DIAGRAMS (2)
  • Page 68 PRINTED CIRCUIT BOARD DIAGRAMS 3 JUC7.820.820...