Toshiba TW40F80 manual High Voltage Circuit, Cr-Block, Anode

Page 77

6. HIGH VOLTAGE CIRCUIT

C2

VCP1 =

 

VCP

 

1

C1 + C2

 

6-1. High Voltage Regulator

 

 

C2

 

 

 

 

VCP2 =

 

VCP

 

2

6-1-1. Outline

C1

+ C2

 

 

Generally, four kinds of methods exist to stabilize a high

VCP =

 

C2

VCP2

 

3

voltage in high voltage output circuits using the FBT:

C1

+ C2

 

 

(1)Stabilization by varying the power supply voltage.

(2) Stabilization by varying L value with a saturable reac-

The VCP2 developed across C2 is DC-clamped with a diode

D1 and the resultant voltage is smoothed with a diode D2

tance connected in series with the primary winding of

and a capacitor C3. Thus processed voltage is obtained at

the FBT.

 

 

 

 

the point B . This voltage is used to provide a base current

 

 

 

(3) Stabilization by varying equivalent capacitance of the

for the transistor Q1 or to flow the collector current. The

resonant capacitor C0.

 

voltage at the point B decreases with the circuit impedance

 

 

 

(4) Stabilization by superimposing a DC or pulse (this

and finally lowers up to a VCE saturation voltage of Q1.

varies the high voltage) on a lower voltage side of the

Then, VCP2 is not clamped by D2 with the voltage at the

high voltage winding of the FBT.

 

 

point B . Since the VCP is expressed as a sum of VCP1 and

 

 

 

In this unit, pulse transformer is eliminated and the regula-

VCP2 as shown by equation

3 , VCP decreases by amount

tor circuit using the method (3) is employed. The block dia-

the VCP2 is decreased. This varies the high voltage.

gram is shown in Fig. 9-19.

 

Q1 collector current is controlled by Q1 base current which

 

 

Z450

 

 

is an output of the comparison inverted amplifier. That is,

 

 

CR-BLOCK

 

 

 

the Q1 base current is controlled by a voltage obtained by

 

 

T461

comparing a detection voltage of the top breeder of the FBT

 

 

FBT

 

 

(9.1V) and a DC voltage of 9V.

 

Hotizonal

 

ANODE

 

output

DY

 

 

 

 

 

 

 

 

 

 

 

 

 

125V

 

Horizontal

C1 LH

FBT

 

 

 

output

LP

 

 

 

 

 

 

PW output

 

 

 

 

 

 

CS

+B

-27V

D1

B

 

 

 

 

C2

D2

 

 

 

 

High voltage Reg.

 

C3

 

 

Q1

 

 

 

High voltage

 

 

 

 

V.

 

Reg.

 

 

output amp

 

Ref.

 

 

 

 

Fig. 9-19 Basic circuit for high voltage regulator

emplyed in the unit

6-1-2. Theory of Operation

Fig. 9-20 shows a basic circuit of the high voltage regulator used in the unit.

The high voltage regulator circuit splits a resonant capacitor C0 to C1 and C2. thereby dividing the collector voltage (VCP) of the H output transistor with C1 and C2.

Here, assume each voltage developed across C1 and C2 as VCP1 and VCP1, respectively,

each relation can be expressed by the above equations 1 ~ 3 .

Fig. 9-20

VCP = VCP1 + VCP2

VCP 1

VCP 2

Fig. 9-21

77

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Page 76 Page 78
Contents TW40F80 Contents Wide Aspect Conversion Circuit Failure Analysis Terminal FUNCTION, Description and Block DiagramSection XI Digital Convergence Circuit Section X Deflection Distortion Correction CircuitImproved Serviceability Section FeatureOutline Merits of BUS System Reduction of Parts CountChassis Model SpecificationsVideo 3 Inputs Front ViewIN-VIDEO Rear View100 Remote Control ViewStarsight Newosd FRO. Surr Chassis LayoutConstruction of Chassis Section II TUNER, IF/MTS/S. PRO Module Circuit Block Major FeaturesOutline RF AGCAudio 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 Section V WAC Circuit Outline ConfigurationCircuit Operation 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 SectionDiagram Main IC Terminal FUNCTION, Description and Block DiagramQY01 MPC1832GTQY01 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 OutlineActual Circuit Output CircuitSawtooth Waveform Generation Circuit OperationOutput Output stage power supply voltage Protection Circuit for V Deflection Stop Linearity Characteristic CorrectionCharacter Correction Up-and Down-ward Extension Correction Up-and Down-ward Linearity BalanceTheory of Operation +35V Over Current Protection CircuitUZ22BSD UZ11BSBKetsu Raster Position Switching CircuitSection IX Horizontal Deflection Circuit Outline SignalHorizontal Drive Circuit Basic Operation of Horizontal DriveOn period OFF period Horizontal Output Circuit Signal DEF/POWER PCBOperation of Basic Circuit FBTT2~t3 Description of the basic circuit T1~t2T3~t4 T4~t6Curve Correction S Capacitor Amplitude CorrectionLinearity Correction LIN Linearity coil Left-right Asymmetrical Correction LIN coilOutline White Peak Bending Correction CircuitOperation Theory EHTBlanking Gate Protector Low Voltage ProtectionAFC High Voltage Generation CircuitABL High Voltage DPC Circuit RegulatorHigh 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 Memory ResetProm PLLPicture 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
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