Toshiba TW40F80 manual Section XI Digital Convergence Circuit Outline, Circuit Description

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SECTION XI: DIGITAL CONVERGENCE CIRCUIT

1. OUTLINE

The digital convergence circuit develops outputs to correct screen distortion and perform color matching. The digital convergence circuit used is of an all digital type and allows good adjustments in comprise with a conventional analog type circuit.

Followings are features of the digital convergence circuit.

1)No adjustment controls (volumes)

2)Registration accuracy increased.

3)Space saved

4)Adjustment by a remote control

The data adjusted are classed into 4 screens for each screen mode. These data are stored on E2PROMs inside the unit. The memory size used in this case is 4 Kbits per one screen.

Each screen adjustment is carried out by calling the adjust- ment screen with the remote control unit supplied and the adjustment is carried out according to the dimensions speci- fied for each screen. The control of the unit is carried out in the I2C format.

2. CIRCUIT DESCRIPTION

2-1. Configuration

Fig. 11-1 shows a block diagram. The digital convergence unit consists of Q701 T7K64 which plays a major role, Q707 PLL circuit which locks a sync entered, Q713 E2PROM to store the data, and Q703-5 D/A converter which develops a correction wave form.

The output signal from the Q703 – 705 D/A converter is amplified and wave form shaped by Q715, Q717 and Q719, and comes out from the unit.

The clock signal for the PLL is adjusted by L719 to a refer- ence frequency of 32 ± 0.1MHz under no input status.

A test pattern generator is also built inside Q701 and devel- ops R, G, B signals and a Ys switching signal.

2-2. Circuit Description

(1)With the power turned on, the unit is reset and enters an operation standby status. And a sync signal of the unit enters external Q707 and Q701. The signal en- tered Q707 is counted down by a counter inside the Q701 and this is used as the reference clock. Q701 works in synchronization with the reference clock sig- nal and the sync signal.

(2)A command is sent from the microcomputer in the unit and Q701 is set up to load the data in Q713 to the in- ternal RAM. (8 (horizontal) x 7 (vertical) x 3 (color))

(3)Q701 transfers a serial data specified to Q703 – 705 according to the RAM data. In this case, interpolation for the RAM data is automatically carried out by a built -in digital filter inside Q701.

(4)The serial data sent from Q701 are digital-analog con- verted by Q703 – 705, thus developing the analog type wave form.

(5)The signals sent from Q703 – 705 are amplified Q715, Q717, Q719, respectively, and then filtered in the next stage to smooth and shape the wave form. Thus pro- cessed signals are used as H and V correction wave forms for R, G, and B signals.

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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 RemarksSDA On Screen FunctionEEPROMQA02 System Block Diagram Local KEY Detection Method Local key assignment FunctionTo TV set Remote Control Code AssignmentCode Function Custom codes are 40-BFH TV set for North U.S.A Code Function Optional Setting for Each Model OPT0 OPT1 Models HEXService Adjustment Entering to Service ModeTest Signal Selection Executing Self Diagnosis Function Failure Diagnosis ProcedureContents to be Confirmed by Customer Understanding Self Diagnosis Indication Self CheckClearing method of self diagnosis result YES Troubleshooting ChartTV does Not Turned on 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 OneScreen 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 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 Circuit Description Section VII 3-DIMENSION Y/C Separator Circuit OutlineConfiguration Circuit 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~t6Curve Correction S Capacitor Amplitude CorrectionLinearity Correction LIN 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 RegulatorHigh Voltage 1. +210V2. +35V Anode High Voltage CircuitCR-BLOCK ED’ ActualFBT CR-BLOCK E H RAY Protection Circuit 23 X-RAY protection circuitOver Current Protection Circuit Functions and Features Block DiagramDiode Modulator Circuit OUTActual 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 Prom ResetMemory PLLPicture Adjustment Service Mode Entering/Exiting ModeSfull Initial screenFirst screen Second screen Key function of remote control unit ENTNormal/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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