Zenith LST 3100A Service Manual

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SERVICE MANUAL

MODEL : LST-3100A

SERVICE MANUAL

P/NO : 3829RVN006Q

AUGUST, 2003

Printed in Korea

CAUTION

BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL.

CONTENTS

SECTION 1 . . . .SUMMARY

SECTION 2 . . . .CABINET & MAIN CHASSIS

SECTION 3 . . . .ELECTRICAL

SECTION 4 . . . .REPLACEMENT PARTS LIST

SECTION 1

SUMMARY

CONTENTS

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS ......... 1-3

SERVICING PRECAUTIONS .................................................................................. 1-4

• General Servicing Precautions

• Insulation Checking Prodedure

• Electrostatically Sensitive Devices

SPECIFICATIONS ................................................................................................... 1-5

1-3

CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY, NEVER PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFACTURER’S APPROVAL. UNAUTHORIZED MODIFICATIONS WILL NOT ONLY VOID THE WARRANTY, BUT MAY LEAD TO YOUR BEING LIABLE FOR ANY RESULTING PROPERTY DAMAGE OR USER INJURY.

SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOU ARE THOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWING SAFETY CHECKS AND SERVICING GUIDELINES. TO DO OTHERWISE, INCREASES THE RISK OF POTENTIAL HAZARDS AND INJURY TO THE USER.

WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTECTION FROM A.C. LINE SHOCK.

SAFETY CHECKS

AFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN CORRCTED. A CHECK SHOULD BE MADE OF THE FOLLOWING.

SUBJECT : FIRE & SHOCK HAZARD

1. BE SURE THAT ALL COMPONENTS ARE POSITIONED IN SUCH A WAY AS TO AVOID POSSIBILITY OF ADJACENT COMPONENT SHORTS. THIS IS ESPECIALLY IMPORTANT ON THOSE MODULES WHICH ARE TRANSPORTED TO AND FROM THE REPAIR SHOP.

2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICES SUCH AS INSULATORS, BARRIERS, COVERS, SHIELDS, STRAIN RELIEFS, POWER SUPPLY CORDS, AND OTHER HARDWARE HAVE BEEN REINSTALLED PER ORIGINAL DESIGN. BE SURE THAT THE SAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEEN DEFEATED.

3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLE COLD SOLDER JOINTS, SOLDER SPLASHES OR SHARP SOLDER POINTS. BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.

4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE OR DETERIORATION TO PARTS AND COMPONENTS. FOR FRAYED LEADS, DAMAGED INSULATION (INCLUDING A.C. CORD). AND REPLACE IF NECESSARY FOLLOW ORIGINAL LAYOUT, LEAD LENGTH AND DRESS.

5. NO LEAD OR COMPONENT SHOULD TOUCH A RECIVING TUBE OR A RESISTOR RATED AT 1 WATT OR MORE. LEAD TENSION AROUND PROTRUNING METAL SURFACES MUST BE AVOIDED.

6. ALL CRITICAL COMPONENTS SUCH AS FUSES, FLAMEPROOF RESISTORS, CAPACITORS, ETC. MUST BE REPLACED WITH EXACT FACTORY TYPES, DO NOT USE REPLACEMENT COMPONENTS OTHER THAN THOSE SPECIFIED OR MAKE UNRECOMMENDED CIRCUIT MODIFICATIONS.

7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN A.C. LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF THE CABINET, (THE CHANNEL SELECTOR KNOB, ANTENNA TERMINALS. HANDLE AND SCREWS) TO BE SURE THE SET IS SAFE TO OPERATE WITHOUT DANGER OF ELECTRICAL SHOCK. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS TEST USE AN A.C. VOLTMETER, HAVING 5000 OHMS PER VOLT OR MORE SENSITIVITY, IN THE FOLLOWING MANNER; CONNECT A 1500 OHM 10 WATT RESISTOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITOR BETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CONDUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME. MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500 OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUG AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75 VOLTS R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANY VALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCK HAZARD AND MUST BE CORRECTED IMMEDIATELY.

SUBJECT: GRAPHIC SYMBOLS

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAG- NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.

SUBJECT : X-RADIATION

1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PERSONNEL COVER THE SUBJECT OF X-RADIATION. THE ONLY POTENTIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PICTURE TUBE. HOWEVER, THIS TUBE DOES NOT EMIT X-RAYS WHEN THE HIGH VOLTAGE IS AT THE FACTORY SPECIFIED LEVEL. THE PROPER VALUE IS GIVEN IN THE APPLICABLE SCHEMATIC. OPERATION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PICTURE TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIRCUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIRABLE LEVELS.

2. ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BE USED. DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD IN COLOR SETS, ALWAYS RE-INSTALL THEM.

3. IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN ACCURATE AND RELIABLE HIGH VOLTAGE METER. THE CALIBRA TION OF THE METER SHOULD BE CHECKED PERIODICALLY AGAINST A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLE AT YOUR DISTRIBUTOR.

4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY THERE IS NO POSSIBILITY OF AN X-RADIATION PROBLEM. EVERY TIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS SHOULD BE RUN UP AND DOWN WHILE MONITORING THE HIGH VOLTAGE WITH A METER TO BE CERTAIN THAT THE HIGH VOLTAGE DOES NOT EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATING CORRECTLY, WE SUGGEST THAT YOU AND YOUR SERVICE ORGANIZATION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGULATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCEDURE. AND THAT THE HIGH VOLTAGE READING BE RECORDER ON EACH CUSTOMER’S INVOICE.

5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN A PRODUCT WITH A PROBLEM OF EXCESSIVE HIGH VOLTAGE, AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT LONGER THAN IS NECESSARY TO LOCATE THE CAUSE OF EXCES SIVE VOLTAGE.

6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES DESCRIBED IN THE APPROPRIATE SCHEMATIC AND DIAGRAMS (WHERE USED).

SUBJECT: IMPLOSION

1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTE GRAL IMPLOSION PROTECTION SYSTEM, BUT CARE SHOULD BE TAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOID SCRATCHING THE TUBE. IF SCRATCHED REPLACE IT.

2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.

SUBJECT : TIPS ON PROPER INSTALLATION

1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBYHOLE OR CLOSELY FITTING SHELF SPACE. OVER OR CLOSE TO HEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW.

2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIO INSTALLATIONS WHERE DEW IS A FACTOR, NEAR STEAM RADIATORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.

3. AVOID PALCEMENT WHERE DRAPERIES MAY OBSTRUCT REAR VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DECORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT OBSTRUCT VENTILATION.

4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMERCIAL MOUNTING KIT. MUST FOLLOW THE FACTORY APPROVED MOUNTING INSTRUCTIONS A PRODUCT MOUNTED TO A SHELF OR PLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENT THICKNESS IN SPACERS) TO PROVIDE ADEQUATE AIR FLOW ACROSS THE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERS MUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGE TEST ON CUSTOMIZED INSTALLATIONS.

5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ON SLOPING SHELF OR A TILTED POSITION, UNLESS THE PRODUCT IS PROPERLY SECURED.

6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITS MOUNTING TO THE CART. CAUTION THE CUSTOMER ON THE HAZARDS OF TRYING TO ROLL A CART WITH SMALL CASTERS ACROSS THRESHOLDS OR DEEP PILE CARPETS.

7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STAND WHICH HAS NOT BEEN LISTED BY UNDERWRITERS LABORATORIES, INC. FOR USE WITH THEIR SPECIFIC MODEL OF TELEVISION RECEIVER OR GENERICALLY APPROVED FOR USE WITH T.V.’S OF THE SAME OR LARGER SCREEN SIZE.

8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS, EXPLAIN THAT A FOREST OF EXTENSIONS SPROUTING FROM A SINGLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO HOME AND FAMILY.

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS

A.C. VOLTMETER

GOOD EARTH GROUND SUCH AS THE WATER PIPE. CONDUIT. ETC

PLACE THIS PROBE ON EACH EXPOSED METAL PART

1-4

SERVICING PRECAUTIONS

CAUTION : Before servicing the STB covered by this service data and its supplements and addends, read and follow the SAFETY PRECAUTIONS. NOTE : if unforeseen circumstances create conflict between the following servicing precautions and any of the safety precautions in this publications, always follow the safety precautions.

Remembers Safety First:

General Servicing Precautions

1. Always unplug the STB AC power cord from the AC power source before: (1) Removing or reinstalling any component, circuit board,

module, or any other assembly.

(2) Disconnection or reconnecting any internal electrical

plug or other electrical connection.

(3) Connecting a test substitute in parallel with an elec-

trolytic capacitor. Caution : A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard.

2. Do not spray chemicals on or near this STB or any of its assemblies.

3. Unless specified otherwise in this service data, clean electrical contacts by applying an appropriate contact cleaning solution to the contacts with a pipe cleaner, cotton-tipped swab, or comparable soft applicator. Unless specified otherwise in this service data, lubrication of contacts is not required.

4. Do not defeat any plug/socket B+ voltage interlocks with whitch instruments covered by this service manual might be equipped.

5. Do not apply AC power to this STB and/or any of its electrical assemblies unless all solid-state device heat sinks are cerrectly installed.

6. Always connect test instrument ground lead to the appropriate ground before connection the test instrument positive lead. Always remove the test instrument ground lead last.

Insulation Checking Procedure

Disconnect the attachment plug from the AC outlet and turn the power on. Connect an insulation resistance meter(500V) to the blades of the attachment plug. The insulation resistance between each blade of the attachment plug and accessible conductive parts (Note 1) should be more than 1Mohm. Note 1 : Accessible Conductive Parts including Metal panels, Input terminals, Earphone jacks, etc.

Electrostatically Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field effect transistors and semiconductor chip components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity.

1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3. Use only a grouned-tip soldering iron to solder or unsolder ES devices.

4. Use only an anti-static solder removal device. Some solder removal devices not classified a “anti-static” can generate electrical charges sufficient to damage ES devices.

5. Do not use freon-propelled chemicals. These can generate electrical charge sufficient to damage ES devices.

6. Do not remove a replacement ES device from its protec tive package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foil, or comparable conductive material).

7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed.

Caution : Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged replacement ES devices. (Normally harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity sufficient to damage an ES device.)

1-5

SPECIFICATIONS

Television System NTSC, DTV standard (1080i, 720p, 480p, 480i)

Channel Coverage Terrestrial: 2-69, Cable: 1-135

Input/Output

ATSC ANT Input ANT IN (1) (ATSC-8VSB over Terrestrial or QAM over cable)

ANT Loop Out Out To TV (1)

DVI Output DVI-HDTV Out (1), DVI-D Single Link connector

1080i, 720p, 480p digital RGB

Component Video Output Component Out (1 Set), Typical RCA type Jack connectors

1080i, 720p, 480p, 480i YPbPr

RGB Output RGB Out (1), 15-pin connector

1080i, 720p, 480p RGB

S-Video Output S-Video Out (1), 4-pin Mini-DIN

480i Y/C

Video Output Video Out (1), Typical RCA type Jack connector

480i Composite

Digital Audio Output Coaxial, Optical (Dolby Digital output)

Analog Audio Output Audio Out (2) (Variable Output Level)

Authorized Service Port 9-pin Serial Port (1)

Dimension (W x H X D) 14.2 x 2.4 x 10.4 inches (360 x 60 x 265 mm)

Weight 7.7 lbs (3.5 kg)

Power Requirements AC 120V, 60Hz

Power Consumption 15W

Environment

Humidity 0 to 99 percent non condensing

Storage Temperature -20 to 60 degrees Celsius (-4 to 140 degrees Fahrenheit)

Operating Temperature 0 to 40 degrees Celsius (32 to 104 degrees Fahrenheit)

Accessories

RF cable . . . . . . . . . . . . . . . . . . . . .1

Video cable . . . . . . . . . . . . . . . . . . .1

Audio (L/R) cable . . . . . . . . . . . . . . .1

Component (YPbPr) cable . . . . . . . .1

Remote Control . . . . . . . . . . . . . . . .1

Batteries (size AA) . . . . . . . . . . . . . .2

2-1

SECTION 2

CABINET & MAIN CHASSIS

CONTENTS

EXPLODED VIEWS .....................................................................................................................2-2

1. Cabinet and Main Frame Section ...........................................................................................2-2

2. Packing Accessory Section....................................................................................................2-3

2-2

EXPLODED VIEWS

1. Cabinet and Main Frame Section

300

A47

463

250

A46

463

A43

A44

A49

280

452

260

320

466

457

465

466

469

470

457

BCD

2-3

2. Packing Accessory Section

808

804

803

801

900

802

803

813

S-VIDEO CABLE

806

RF CABLE

823

TELEPHONE LINE

820

PLUG ASS'Y(3WAY)

PACKING SHEET

PACKING

BATTERY

822

SMART CARD

REMOCON

BOX CARTONX

PACKING

OWNER'S MANUAL

OPTIONAL PARTS

811

812

PLUG ASS'Y 1WAY

PLUG ASS'Y 2WAY

3-1

SECTION 3

ELECTRICAL

CONTENTS

SOFTWARE CORRUPTION PROBLEM.....................................................................................................3-2

ELECTRICAL TROUBLESHOOTING GUIDE............................................................................................3-5

1. POWER(SMPS) CIRCUIT.........................................................................................................................3-5

2. AUDIO CIRCUIT .......................................................................................................................................3-7

1) NO ATSC AUDIO.....................................................................................................................................3-7

2) NO OPTICAL OUTPUT AUDIO...............................................................................................................3-11

3) NO COAXIAL OUTPUT AUDIO ..............................................................................................................3-12

3. CPU (SYSTEM CONTROL) TROUBLESHOOTING ..............................................................................3-14

4. VIDEO TROUBLESHOOTING FLOW ....................................................................................................3-21

5. ATSC/ QAM FRONT- END TROUBLESHOOTING FLOW ....................................................................3-31

6. FRONT PANEL TROUBLESHOOTING FLOW......................................................................................3-32

OVERALL BLOCK DIAGRAM.........................................................................................................................3-34

1. OVERALL BLOCK DIAGRAM 1 ............................................................................................................3-34

2. OVERALL BLOCK DIAGRAM 2 ............................................................................................................3-36

3. OVERALL BLOCK DIAGRAM 3 ............................................................................................................3-38

BLOCK DIAGRAM & SIGNAL FLOW.............................................................................................................3-40

1. POWER(SMPS) BLOCK DIAGRAM ......................................................................................................3-40

2. SYSTEM CONTRL BLOCK DIAGRAM..................................................................................................3-42

3. AUDIO PROCESSING BLOCK DIAGRAM............................................................................................3-44

4. VIDEO PROCESSING BLOCK DIAGRAM ............................................................................................3-46

CIRCUIT DIAGRAM .........................................................................................................................................3-48

1. POWER(SMPS) CIRCUIT DIAGRAM ....................................................................................................3-48

2. CPU, AUDIO, POWER CIRCUIT DIAGRAM..........................................................................................3-50

3. HD2, TUNER, DVI CIRCUIT DIAGRAM.................................................................................................3-52

4. ATSCII-STB CIRCUIT DIAGRAM...........................................................................................................3-54

5. FRONT CIRCUIT DIAGRAM ..................................................................................................................3-56

PRINTED CIRCUIT DIAGRAMS......................................................................................................................3-58

1. DIGITAL MAIN P.C.BOARD(BOTTOM)..................................................................................................3-58

2. DIGITAL MAIN P.C.BOARD(TOP)..........................................................................................................3-60

3. FRONT P.C.BOARD ...............................................................................................................................3-62

4. POWER P.C.BOARD ..............................................................................................................................3-62

SOFTWARE CORRUPTION PROBLEM

3-2

1. Open window display for Serial Communication like above.

- You can use almost kinds of serial communication programs, but we send the terminal (LG Term) which is now used on our side.

2. Create “Setup-> Serial Port” like the display. (However, the port depends upon the user environment so that you need to create properly.)

3. Create “Setup-> Terminal” like the above display.

3-3

4. After completing all set-up process, press d key in the terminal and impress STB power. At this time, you should pull up the plug and then pull into the socket again.

- You have another choice. When activating, please enter “klLST3100”, “ENTER” and then “F10” keys in sequence. Once the command mode is up, you can download it even in your “Reset” command.

5. When above display shows up, you can download applications. You can input keys at the prompt.

6. Press Enter Key several times to input new command. Input serial download command as “sto ser” like above example and then press Enter key.

7. This is the condition you can download application program from STB.

3-4

8. In the downloadable condition, select °∞File->Send File°±. You can watch one more dis- play like above. You should find °∞ram.biz°∞ file in this new display and open it to start downloading.

9. You can see the downloading process from display and it takes about 2 minutes to complete. After downloading, the message °∞Please write data into the Flash ROM°± would show up. (You may experience errors of downloading. Then, follow from No. 6 again.

10. Above message shows that you succeed to write application program into the Flash.

Restart the power source, or input °∞b flash°± in this display to activate properly. (If you have no response, please input command again.)

3-5

ELECTRICAL TROUBLESHOOTING GUIDE

1. Power(SMPS) CIRCUIT

YES

YES YES

YES

(1) No 5.0VA

Check or Replace the D106

Check the ‘PWR CTL “H”’ signal from µ-com

(2) No 5.0V

(3) No 3.3V

No 5.0VA

Is the F101 normal?

Is the R105 Normal?

Is the BD101 normal?

Is Vcc (13V - 16V) supplied to IC101 Pin7?

Are the D106 normal?

Is there about 2.5V

at the IC103 Pin1?

Is the D105 normal?

Is the D109 normal?

Replace the F101.

(Use the same Fuse)

Replace the BD101.

Replace the R105.

Is the D103 normal?

Check or Replace the D106.

Replace the D106.

Replace the IC103.

Replace the D105.

Replace the D109.

Replace the D110.

No 3.3V

Is there about 3.8V at the IC153 pin1?

Is there about 3.3V~ 5V at the IC153 pin4?

YES

Check the IC153 and Replace

Check or Replace the D105

Check the ‘PWR CTL “H”’ signal from µ-com

Is there about 5.4V at the IC152 pin1?

Is there about 3.3V~5V at the IC152 pin4?

YES

Check the IC152 and Replace

Is the D110 normal?

Replace the D108.

Is the D108 Normal?

NO 5.0V

YES

Power Line of Main PCB is short

Replace the D107.

Is the D107 Normal?

3-6

YES

(4) No 12VA

Is there about 13V at the IC155 pin1?

Is there about 3.3V~5V at the IC155 pin4?

Check the IC155 and Replace

Check or Replace the D109

Check the ‘PWR CTL “H”’ signal from µ-com

YES

(6) No VFD

No VFD

Is The R123 Normal?

Is The D107 Normal?

Is The ZD102 Normal?

Check and Replace the D108

Replace the R123

Replace the R107

Replace the ZD102

YES

(5) No 30VA

No 30VA

Is The ZD110 Normal?

Check and Replace the D110

Replace the ZD101

3-7

2. AUDIO CIRCUIT

1) NO ATSC AUDIO

YES

(1) Check IC110 and Surroundings

5V is supplied to IC110(14)?

12.2880MHz clock is input to IC110 (5)? Fig. 01

IC110(13) is grounded?

48KHz clock is output from IC110 (4)? Fig. 02

Data Signal is input to IC110(2)?

Fig. 03

YES

Analog Audio Signal from IC110 (12,15)? Fig. 04

Check the Power Supply Part.

Check 12.2880MHz Clock output at IC200(H5).

Check 48KHz Clock ouput at IC200 (G5)

Check soldering.

Check Data Signal at IC200(G3)

3-8

Fig. 01 12.2880MHz clock

Fig. 02 48KHz clock

Fig. 04 Analog Audio SignalFig. 03 Data Signal

3-9

Fig. 05 Analog Audio Signal

YES

(2) Check IC112 and Surroundings

(3) Check Q102, Q103, Q109, Q110 and Surroundings

(4) Check Output Jack and Surroundings

59V is supplied to IC112(8)?

Analog audio signal is output from IC112(1, 7)? Fig. 05

Analog audio signal is output from Q102, Q103, Q109, Q110(1)? Fig. 06

9V is supplied to Q102, Q103, Q109,Q110(3)?

Check CN300(VARIABLE_ L, VARIABLE_ R, MONITOR_ L, MONITOR_ R) And their surroundings

Check Power Supply Part

Check IC112 and surroundings

Check Power Supply Part

Check Q102, Q103, Q109, Q110 and surroundings

3-10

Fig. 06 Analog Audio Signal

3-11

2) NO OPTICAL OUTPUT AUDIO

YES

SPDIF pulse is output from IC200 (F3)? Fig. 07

Check CN103 and surrounding

Check IC200 and surroundings

3-12

3) NO COAXIAL OUTPUT AUDIO

YES

5V is supplied to Q100(3)?

SPDIF pulse is output from IC200(F3)? Fig. 07

SPDIF pulse is output from Q100(1)? Fig. 08

Check CN300(S6, G6) and their surroundings

Check Power Supply Part

Check IC200 and surroundings

Check Q100, Q101 and surroundings

3-13

Fig. 07 ,Digital Audio Signal

Fig. 08

Coaxial Digital Audio Signal

3. CPU (System Control) Troubleshooting

YES

Start

Is Power supplied normally?

Is each clock OK?

YES

Is each reset OK at the time of power- on reset?

YES

Is each chip selection OK?

YES

Is each I2C channel OK?

YES

Are messages output through RS- 232C port on PC terminal?

YES

End

Check Power : Refer to (A)

Check each clock : Refer to (B)

Check reset circuit : Refer to (C)

Check each chip selection : Refer to (D)

Check each I2C channel : Refer to (E)

Check RS- 232C circuit : Refer to (G)

3-14

+ 52 hidden pages

Zenith LST 3100A Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual