Toshiba TW40F80 manual Section IX Horizontal Deflection Circuit Outline, Horizontal Drive Circuit

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SECTION IX: HORIZONTAL DEFLECTION CIRCUIT

1. OUTLINE

The H deflection circuit works to deflect a beam from left to right by flowing a sawtooth waveform of 15.625 kHz/15.735 kHz into the DY H deflection coil.

2. HORIZONTAL DRIVE CIRCUIT

The H drive circuit works to start the H output circuit by applying H VCC (Q501 DEF power source) to pin 22 of Q501 (TA1222N) and a bias to the H drive transistor Q402 at the main power on.

2-1. Theory of Operation

(1)When the power switch is on, the main power supply of 125V starts to rise. At the same time, AF power sup- ply 38V also rises.

(2)With 38V line risen, Q430 base voltage which is cre- ated by dividing the audio power with R433 and D430 also rises. Then, the transistor Q430 turns on and the H VCC is applied from the audio power line through R432 and D431 to pin 22 of Q501.

R432

Q430

D431

 

 

35V

 

 

 

 

R433

D430

 

BB81

 

 

 

 

 

 

 

 

81

81

L400

 

 

BB80

 

 

 

 

 

Q501

22 H Vcc

SIGNAL

 

 

 

 

 

C431 C430

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 9-1 H drive circuit block diagram

3. BASIC OPERATION OF HORIZONTAL DRIVE

A sufficient current must flow into base of the horizontal output transistor to rapidly make it into a saturated (ON) condition or a cut off (OFF) condition. For this purpose, a drive amplifier is provided between the oscillator circuit and the output circuit to amplify and to waveshape the pulse volt- age.

3-1. Theory of Operation

(1)The horizontal drive circuit works as a so called switch- ing circuit which applies a pulse voltage to the output transistor base and makes the transistor on when the voltage swings in forward direction and off in reverse direction.

(2)To turn on the output transistor completely and to make the internal impedance low, a sufficiently high, for- ward drive voltage must be applied to the base and heavy base current ib must be flown. On the contrary, to completely turn off the transistor, a sufficiently high, reverse voltage must be applied to the base.

(3)When the transistor is on (collector current is maxi- mum) condition with the sufficiently high forward volt- age applied to the base, the transistor can not be turned off immediately, if a reverse base bias is applied to the base because minority carriers storaged in the base can not be reduced to zero instantly. That is, a reverse cur- rent flows through an external circuit and gradually reduces to zero. The time lag required for the base cur- rent to disappear is called a storage time and falling time.

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Contents TW40F80 Contents Terminal FUNCTION, Description and Block Diagram Wide Aspect Conversion Circuit Failure AnalysisSection X Deflection Distortion Correction Circuit Section XI Digital Convergence CircuitOutline Merits of BUS System Section FeatureImproved Serviceability Reduction of Parts CountSpecifications Chassis ModelFront View Video 3 InputsRear View IN-VIDEORemote Control View 100Chassis Layout Starsight Newosd FRO. SurrConstruction of Chassis Outline Major FeaturesSection II TUNER, IF/MTS/S. PRO Module Circuit Block RF AGCAudio Multiplex Demodulation Circuit A.PRO block diagram A.PRO Section Audio ProcessorConfiguration of the audio circuit and signal flow are given POP Tuner Terminal No NameOperation of Channel Selection Circuit Microcomputer SDA SCLMicrocomputer Terminal Function Microcomputer Terminal Name and Operation Logic Terminal Name Function In/Out Logic RemarksOn Screen Function EEPROMQA02SDA System Block Diagram Local KEY Detection Method Local key assignment FunctionRemote Control Code Assignment Code FunctionTo TV set Custom codes are 40-BFH TV set for North U.S.A Code Function Optional Setting for Each Model OPT0 OPT1 Models HEXEntering to Service Mode Test Signal SelectionService Adjustment Failure Diagnosis Procedure Contents to be Confirmed by CustomerExecuting Self Diagnosis Function Understanding Self Diagnosis Indication Self CheckClearing method of self diagnosis result Troubleshooting Chart TV does Not Turned onYES No Acception of KEY-IN No Picture Snow NoiseMemory Circuit Check No Indication On ScreenSection IV DVD Switch Circuit DVD Switch Block Diagram Outline Circuit Operation ConfigurationSection V WAC Circuit Outline OperationWide aspect conversion unit block diagram PB6348 Pin Function Pin function of TC9097F QFP 80 pinNames and functions of TC9097F Name FunctionVFL2 Block Diagram TC9097F system block diagramWide Aspect Conversion Circuit Failure Analysis Procedures E2PROM OK?Adjustment Method Raster Horizontal OneSection VI Dual Circuit Outline Principles of OperationScreen multi-search process System Component Diagram of Dual Unit Video/Color/Deflection Process Section OSD Sub Screen Process Section Sub screen process sectionMain/Sub Screen Superimposing Section Main/Sub screen superimposing sectionQY01 Main IC Terminal FUNCTION, Description and Block DiagramDiagram MPC1832GTQY01 mPC1832GT pin layout QY03 TC9092AF internal block diagram QY03 TC9092AF pin layout QY03 TC9092AF pin list No Pin name Pin function CKWMRD1 QY10/QY11 M518221-30ZS internal block diagram Section VII 3-DIMENSION Y/C Separator Circuit Outline Configuration Circuit DescriptionCircuit Description Terminal description PZ01 Section Viii Vertical Output Circuit Outline Theory of OperationSawtooth Waveform Generation Output CircuitActual Circuit Circuit OperationOutput Output stage power supply voltage Character Correction Up-and Down-ward Extension Correction Linearity Characteristic CorrectionProtection Circuit for V Deflection Stop Up-and Down-ward Linearity BalanceUZ22BSD +35V Over Current Protection CircuitTheory of Operation UZ11BSBRaster Position Switching Circuit KetsuHorizontal Drive Circuit SignalSection IX Horizontal Deflection Circuit Outline Basic Operation of Horizontal DriveOn period OFF period Operation of Basic Circuit Signal DEF/POWER PCBHorizontal Output Circuit FBTT3~t4 Description of the basic circuit T1~t2T2~t3 T4~t6Amplitude Correction Linearity Correction LINCurve Correction S Capacitor Left-right Asymmetrical Correction LIN coil Linearity coilOperation Theory White Peak Bending Correction CircuitOutline EHTBlanking Low Voltage Protection Gate ProtectorABL High Voltage Generation CircuitAFC High Voltage DPC Circuit Regulator1. +210V 2. +35VHigh Voltage High Voltage Circuit CR-BLOCKAnode Actual FBT CR-BLOCK E HED’ RAY Protection Circuit 23 X-RAY protection circuitOver Current Protection Circuit Functions and Features Block DiagramDiode Modulator Circuit OUTActual Circuit Basic Operation and Current Path Later Half Scanning PeriodFirst Half Scanning Period Later Half of Flyback Period First Half of Scanning PeriodP.T Section XI Digital Convergence Circuit Outline Prom ResetMemory PLLPicture Adjustment Service Mode Entering/Exiting ModeInitial screen First screen Second screenSfull Key function of remote control unit ENTOperation procedure Each Screen Adjustment MethodNormal/Full Theater Wide1 Theater Wide 269.5 When CRT is Replaced When Convergence Unit is ReplacedCase Study Troubleshooting Adjusting Procedure in Replacing CRTAdjusting Procedure in Replacing Convergence Unit/Main Def Convergence Output Circuit Convergence Block Diagram Convergence Troubleshooting Chart Main Unit
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