Vizio GV42L HDTV, L42HDTV10A service manual Trouble of DC-DC Converter

Page 94

TROUBLE OF DC-DC CONVERTER

Start

N0

J7 PIN10,11,12

Yes

N0

J7 PIN 2,3,4

Yes

N0

U1 pin 5 6 7 8

Yes

N0

U4 pin2

Yes

N0

U6 pin 2

YesN0

U5 pin2

Yes

N0

U8 pin2

U7&U8&U10 pin2

The voltage is about + 5V 1.Check power board 2.Check power cable connection J7

The voltage is about + 12V while power switch on

1.J7 connection good 2.Check J7 Pin1 is up to 3V? 3.Check power board

The voltage is about +5V while power switch on

1.J1 connection good

2.Check U11 GPIO_7 Pin

The voltage is about	+3.3V
1.J1 to connection good?
2.Check U4
The voltage is about	+3.3V
1.J1 to connection good?
2.Check U6
The voltage is about	+1.8V while
power switch on
1.Check U5
The voltage is about	+3.3V
while power switch on
1.Check J1 Connect
2.Check U8
The voltage is about	+1.8V
while power switch on
1.Check J1 Connect

2.Check U7&U8&U10

END

CONFIDENTIAL – DO NOT COPY	Page 9-5
	File No. SG-0198

Image 94

Contents Vizio GV42L Hdtv Table of Contents Vinc Features Optical Characteristics SpecificationPower Supply Mounting Precautions Dimensions Physical dimension Width 1066 mmWeight Physical weight SpeakerOperating Precautions Handling Precautions for Protection On Screen Display TV SourceRGB Mode AV Component Mode Hdmi MODE： Confidential do not Copy Factory preset timings Pin Assignment Hdmi Connect PIN Assignment Type TV RF connector RGB Signal Main Board I/o Connections Theory of Circuit Operation MT8202 Application Video input YPbPr/Scart/D-connectorDecoder Digital port Support FormatsSupporting OSD mirror and upside down 2D-Graphic/OSD processorI/O ports are configured as follows： Microprocessor interfaceVideo processor 1.Color Management Dram Usage DDR Sdram V58C2128164SBI5 Application Pin description Command Truth Table Power-UpFunctional DescriptionMode Register Set MRS Precharge Bank Activate Command Read Operation Precharge Timing During Read OperationBurst Stop Command Precharge Timing During Write OperationBurst Write Operation MX29LV160BTTC Flash Application Block Diagram Command Definitions Write COMMANDS/COMMAND Sequences READ/RESET Command Reading Array Data WM8776 ApplicationAudio sample rate Slave mode Confidential do not Copy MT8293 Application Hdcp Decryption Tmds Digital CoreActive port detection Video Data Conversion and Video OutputI2c Interface to Display Controller TDA8946 ApplicationBlock diagram Input configuration Output power measurement Mode selection MT5351 ApplicationGeneral Feature List CGMS/WSS Confidential do not Copy MX29LV320BTTC Flash Application Confidential do not Copy Block Diagram BUS OPERATION--1 Write COMMANDS/COMMAND Sequences BUS OPERATION--2Table A. MX29LV320AT/B Command Definitions Standby Mode Reset OperationSoftware Command Definitions Write Protect WPWrite Operation Status Table B. Write Operation StatusFig C. Command Write Operation Fig D. Read Timing Waveforms Fig E. Reset Timing Waveform DDR Sdram NT5DS16M16CS-5T Application Block Diagram 16Mb xFunctional Description Pin Configuration 400mil Tsop II x4 / x8 Mode Register Operation Operating Mode Extended Mode Register Extended Mode Register DefinitionTruth Table a Commands ActiveAuto Refresh ReadWrite Self RefreshOperations ReadsRandom Read Accesses CAS Latencies Burst Length = 2, 4 or Read Command Write Command Data Input Write Data Output Read Waveforms PC MODE1366X768 60HZCH1 Green # FB27 CH2 Vgavsync L22 CH1 Vgal R193 CH2 Avol R194 CH1 PCL CE70+ PCL CE70 AV&TV Mode AV1/AV2/TV Video Confidential do not Copy CH1 Dacbclk U23 PIN4 CH1 Dacmclk U23 PIN5 Component Mode Component 1/2 CH1YCBCRL2L19 CH2 2A33 U22 PIN11 CH1 AVL CE71+CH2 Auspl R304 Hdmi 1&2 Confidential do not Copy DTV HD Confidential do not Copy CH1 Vovsync DU9 PIN W1 CH1 Vode DU9 PIN W2 CH1 Vopclk DU9 PIN Trouble shooting Monitor Display Nothing PC ModeTV, Composite VIDEO1, 2, S-VIDEO is not Display Correctly COMPONENT1, 2 is not Display Correctly Hdmi is not Display Correctly Trouble of DC-DC Converter Trouble of DDC Reading Block Diagram System Block Diagram Wxga panelConfidential do not Copy Main Board Block Diagram Page Page Page Page Page Page Page