On period OFF period | Toshiba TW40F80 specification

(4)To shorten the storage time and the falling time, a suf- ficiently high reverse bias voltage must be applied to allow a heavy reverse current to flow. This operation also stabilizes operation of the horizontal output tran- sistor.

+

0

-

+

ib

0

V-

(a)

Fig. 9-2

On period

OFF period

t Input waveform (b)

Forward current

t Base current (c) Reverse

current

Falling time

Storage time

3-2. Circuit Description

In the N5SS chassis, the off drive system is employed.

(1)When Q1 inside Q501 is turned on, Q402 base is for- ward biased through 9V ® pin 22 of Q501 (H. VCC)

® pin 23 of Q501 (H. Out) ® R411/R410 resistor di- vider, and then, Q402 collector current flows through 125V ® R416 ® T401. In this case, the H output tran- sistor Q404 turns on with the base-emitter reverse bi- ased because of the off drive system employed.

Q501

H. Vcc

22

(2)On the contrary, when Q1 inside IC501 is off (pin 8 is 0V), base-emitter bias of Q402 becomes 0V and Q402 turns off, and a collector pulse as shown in Fig. 9-3 develops at the collector.

The voltage is stepped down and Q404 is forward bi- ased with this voltage, thus turning on Q404.

(3)In this way, by stepping down the voltage developed at primary winding of the drive transformer and by ap- plying it to Q404, a sufficient base current flows into Q404 base, thereby switching the Q404.

T401

H drive

transistor

C431	C417

Q1

R411

23

R410

Q402

H drive

transistor

9V

Fig. 9-3

1

3

R415

		Q404
		H output
2	4	transistor
2	4

C413

	+	V1
	+	V2
	R416	V2

C416

+125V

VCP

Q402 Q402

OFF ON

0V

0V

67

Image 67

Toshiba TW40F80 manual On period OFF period

Contents

TW40F80 Contents Wide Aspect Conversion Circuit Failure Analysis Terminal FUNCTION, Description and Block Diagram Section XI Digital Convergence Circuit Section X Deflection Distortion Correction Circuit Reduction of Parts Count Section FeatureImproved Serviceability Outline Merits of BUS System Chassis Model Specifications Video 3 Inputs Front View IN-VIDEO Rear View 100 Remote Control View Starsight Newosd FRO. Surr Chassis Layout Construction of Chassis RF AGC Major FeaturesSection II TUNER, IF/MTS/S. PRO Module Circuit Block Outline Audio Multiplex Demodulation Circuit A.PRO Section Audio Processor A.PRO block diagram Configuration of the audio circuit and signal flow are given Terminal No Name POP Tuner Operation of Channel Selection Circuit SDA SCL Microcomputer Microcomputer Terminal Function Terminal Name Function In/Out Logic Remarks Microcomputer Terminal Name and Operation Logic EEPROMQA02 On Screen FunctionSDA System Block Diagram Local key assignment Function Local KEY Detection Method Code Function Remote Control Code AssignmentTo TV set Custom codes are 40-BFH TV set for North U.S.A Code Function OPT0 OPT1 Models HEX Optional Setting for Each Model Test Signal Selection Entering to Service ModeService Adjustment Contents to be Confirmed by Customer Failure Diagnosis ProcedureExecuting Self Diagnosis Function Self Check Understanding Self Diagnosis Indication Clearing method of self diagnosis result TV does Not Turned on Troubleshooting ChartYES No Picture Snow Noise No Acception of KEY-IN No Indication On Screen Memory Circuit Check Section IV DVD Switch Circuit DVD Switch Block Diagram Outline Operation ConfigurationSection V WAC Circuit Outline Circuit Operation Wide aspect conversion unit block diagram PB6348 Pin function of TC9097F QFP 80 pin Pin Function Name Function Names and functions of TC9097F VFL2 TC9097F system block diagram Block Diagram E2PROM OK? Wide Aspect Conversion Circuit Failure Analysis Procedures Raster Horizontal One Adjustment Method Principles of Operation Section VI Dual Circuit OutlineScreen multi-search process System Component Diagram of Dual Unit Video/Color/Deflection Process Section OSD Sub screen process section Sub Screen Process Section Main/Sub screen superimposing section Main/Sub Screen Superimposing Section MPC1832GT Main IC Terminal FUNCTION, Description and Block DiagramDiagram QY01 QY01 mPC1832GT pin layout QY03 TC9092AF internal block diagram QY03 TC9092AF pin layout CKW QY03 TC9092AF pin list No Pin name Pin function MRD1 QY10/QY11 M518221-30ZS internal block diagram Configuration Circuit Description Section VII 3-DIMENSION Y/C Separator Circuit OutlineCircuit Description Terminal description PZ01 Theory of Operation Section Viii Vertical Output Circuit Outline Circuit Operation Output CircuitActual Circuit Sawtooth Waveform Generation Output 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 Correction UZ11BSB +35V Over Current Protection CircuitTheory of Operation UZ22BSD Ketsu Raster Position Switching Circuit Basic Operation of Horizontal Drive SignalSection IX Horizontal Deflection Circuit Outline Horizontal Drive Circuit On period OFF period FBT Signal DEF/POWER PCBHorizontal Output Circuit Operation of Basic Circuit T4~t6 Description of the basic circuit T1~t2T2~t3 T3~t4 Linearity Correction LIN Amplitude CorrectionCurve Correction S Capacitor Linearity coil Left-right Asymmetrical Correction LIN coil EHT White Peak Bending Correction CircuitOutline Operation Theory Blanking Gate Protector Low Voltage Protection High Voltage DPC Circuit Regulator High Voltage Generation CircuitAFC ABL 2. +35V 1. +210VHigh Voltage CR-BLOCK High Voltage CircuitAnode FBT CR-BLOCK E H ActualED’ 23 X-RAY protection circuit RAY Protection Circuit Over Current Protection Circuit Block Diagram Functions and Features OUT Diode Modulator Circuit Actual Circuit Later Half Scanning Period Basic Operation and Current PathFirst Half Scanning Period First Half of Scanning Period Later Half of Flyback PeriodP.T Section XI Digital Convergence Circuit Outline PLL ResetMemory Prom Picture Adjustment Entering/Exiting Mode Service Mode First screen Second screen Initial screenSfull ENT Key function of remote control unit Each Screen Adjustment Method Operation procedureNormal/Full Theater Wide1 Theater Wide 269.5 When Convergence Unit is Replaced When CRT is ReplacedCase Study Adjusting Procedure in Replacing CRT TroubleshootingAdjusting Procedure in Replacing Convergence Unit/Main Def Convergence Output Circuit Convergence Block Diagram Convergence Troubleshooting Chart Main Unit