Toshiba TW40F80 manual Section Viii Vertical Output Circuit Outline, Theory of Operation

Page 59

SECTION VIII: VERTICAL OUTPUT CIRCUIT

1. OUTLINE

The sync separation circuit, V pulse circuit, and blanking circuit are provided inside Q501 (TA1222AN). The saw tooth wave generation circuit and amplifier (V driver circuit) are provided inside Q302 (TA8859AP).

Q301 (LA7833S) contains the pump up circuit and the output circuit. V screen position switching function which lowers the V raster position by flowing an opposite DC current into the deflection yoke. This circuit is used selecting SUBTITLE and CINEMA MODE.

WAC

PULSE DELAY

( I2C BUS)

MICROPROCESSOR

( I2C BUS)

Q302 TA8859AP

SAWTOOTH

WAVE

GENERATOR

AMP

CONTROL CIRCUIT

Q301 LA7833S

PUMP UP

CIRCUIT

OUTPUT

FEEDBACK

DEFLECTION

YOKE

Q501 TA1222AN

V/C/D LSI

SYNC SEP.V PULSE/

BLANKING

V-RASTER SHIFT

CIRCUIT

AUTO LIVE

MICROPROCESSOR

V-BLK

Fig. 8-1

1-1. Theory of Operation

The purpose of the V output circuit is to provide a sawtooth wave signal with good linearity in V period to the deflection yoke.

When a switch S is opened, an electric charge charged up to a reference voltage VP discharges in an constant current rate, and a reference sawtooth voltage generates at point a .

This voltage is applied to (+) input (non-inverted input) of an differential amplifier, A. As the amplification factor of A is sufficiently high, a deflection current flows so that the voltage V2 at point c becomes equal to the voltage at point

a .

	Vp	S: Switch
	Vp	Differential
		Differential
		amplifier

L

a			A
a
V1	R1	C2	R2
V1

C2	c
	c
	V2
R3

Fig. 8-2

59

Image 59

Contents TW40F80 Contents Wide Aspect Conversion Circuit Failure Analysis Terminal FUNCTION, Description and Block DiagramSection XI Digital Convergence Circuit Section X Deflection Distortion Correction CircuitReduction of Parts Count Section FeatureImproved Serviceability Outline Merits of BUS SystemChassis Model SpecificationsVideo 3 Inputs Front ViewIN-VIDEO Rear View100 Remote Control ViewStarsight Newosd FRO. Surr Chassis LayoutConstruction of Chassis RF AGC Major FeaturesSection II TUNER, IF/MTS/S. PRO Module Circuit Block OutlineAudio Multiplex Demodulation Circuit A.PRO Section Audio Processor A.PRO block diagramConfiguration of the audio circuit and signal flow are given Terminal No Name POP TunerOperation of Channel Selection Circuit SDA SCL MicrocomputerMicrocomputer Terminal Function Terminal Name Function In/Out Logic Remarks Microcomputer Terminal Name and Operation LogicSDA On Screen FunctionEEPROMQA02 System Block Diagram Local key assignment Function Local KEY Detection MethodTo TV set Remote Control Code AssignmentCode Function Custom codes are 40-BFH TV set for North U.S.A Code Function OPT0 OPT1 Models HEX Optional Setting for Each ModelService Adjustment Entering to Service ModeTest Signal Selection Executing Self Diagnosis Function Failure Diagnosis ProcedureContents to be Confirmed by Customer Self Check Understanding Self Diagnosis IndicationClearing method of self diagnosis result YES Troubleshooting ChartTV does Not Turned on No Picture Snow Noise No Acception of KEY-INNo Indication On Screen Memory Circuit CheckSection IV DVD Switch Circuit DVD Switch Block Diagram Outline Operation ConfigurationSection V WAC Circuit Outline Circuit OperationWide aspect conversion unit block diagram PB6348 Pin function of TC9097F QFP 80 pin Pin FunctionName Function Names and functions of TC9097FVFL2 TC9097F system block diagram Block DiagramE2PROM OK? Wide Aspect Conversion Circuit Failure Analysis ProceduresRaster Horizontal One Adjustment MethodScreen multi-search process Section VI Dual Circuit OutlinePrinciples of Operation 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 SectionMPC1832GT Main IC Terminal FUNCTION, Description and Block DiagramDiagram QY01QY01 mPC1832GT pin layout QY03 TC9092AF internal block diagram QY03 TC9092AF pin layout CKW QY03 TC9092AF pin list No Pin name Pin functionMRD1 QY10/QY11 M518221-30ZS internal block diagram Circuit Description Section VII 3-DIMENSION Y/C Separator Circuit OutlineConfiguration Circuit Description Terminal description PZ01 Theory of Operation Section Viii Vertical Output Circuit OutlineCircuit Operation Output CircuitActual Circuit Sawtooth Waveform GenerationOutput Output stage power supply voltage Up-and Down-ward Linearity Balance Linearity Characteristic CorrectionProtection Circuit for V Deflection Stop Character Correction Up-and Down-ward Extension CorrectionUZ11BSB +35V Over Current Protection CircuitTheory of Operation UZ22BSDKetsu Raster Position Switching CircuitBasic Operation of Horizontal Drive SignalSection IX Horizontal Deflection Circuit Outline Horizontal Drive CircuitOn period OFF period FBT Signal DEF/POWER PCBHorizontal Output Circuit Operation of Basic CircuitT4~t6 Description of the basic circuit T1~t2T2~t3 T3~t4Curve Correction S Capacitor Amplitude CorrectionLinearity Correction LIN Linearity coil Left-right Asymmetrical Correction LIN coilEHT White Peak Bending Correction CircuitOutline Operation TheoryBlanking Gate Protector Low Voltage ProtectionHigh Voltage DPC Circuit Regulator High Voltage Generation CircuitAFC ABLHigh Voltage 1. +210V2. +35V Anode High Voltage CircuitCR-BLOCK ED’ ActualFBT CR-BLOCK E H 23 X-RAY protection circuit RAY Protection CircuitOver Current Protection Circuit Block Diagram Functions and FeaturesOUT Diode Modulator CircuitActual Circuit First Half Scanning Period Basic Operation and Current PathLater Half Scanning Period P.T Later Half of Flyback PeriodFirst Half of Scanning Period Section XI Digital Convergence Circuit Outline PLL ResetMemory PromPicture Adjustment Entering/Exiting Mode Service ModeSfull Initial screenFirst screen Second screen ENT Key function of remote control unitNormal/Full Operation procedureEach Screen Adjustment Method Theater Wide1 Theater Wide 269.5 Case Study When CRT is ReplacedWhen Convergence Unit is Replaced Adjusting Procedure in Replacing Convergence Unit/Main Def TroubleshootingAdjusting Procedure in Replacing CRT Convergence Output Circuit Convergence Block Diagram Convergence Troubleshooting Chart Main Unit