Zenith LST 4600A Service Manual

MODEL : HCS6000A(LST-4600A)

SERVICE MANUAL

P/NO : 3829R

MAY, 2004

Printed in Korea

HD/SD PERSONAL VIDEO RECORDER & RECEIVER WITH GEMSTAR

SERVICE MANUAL

CAUTION

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

1-1

SECTION 1

SUMMARY

CONTENTS

INTRODUCTION ......................................................................................................1-2

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

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

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

LOCATION OF CUSTOMER CONTROLS ...............................................................1-7

1-2

INTRODUCTION

- Digital/Analog broadcasting recorder/receiver [HD/SD PERSONAL VIDEO RECORDER & RECEIVER] or PVR(Personal Video Recorder)-STB(Set-Top Box) receives the ground wave HD Digital broadcasting program /Analog NTSC or Cable broadcasting program and saves a video and audio signal at a HDD with a specific form or offers additional related services..

- Configuration The PCU is the IBM PPC405GP of the PowerPC series supporting PCI Bus I/F for PVR, and the tuner receives a digital ground wave and transfers it as a TP signal, transmitting the NTSC signal of the ground wave/the cable signal and transferring the audio signal to the SIF. The MPEG Decoder uses the HD-II supporting MP@HL built with the AC-3 Decoder. The PVR section transforms the TP data of a digital TV signal and an analog audio/video signal into the TP by using the MPEG-II Encoder and saves only the necessary data to the HDD via the IDE I/F Chip.

Overall configuration

- System section CPU, Main Memory, MPEG-II Decoder, Flash Memory, and System CPLD.

- MPEG Video/Audio Decoder section HD-2, Memory, PLL IC, Audio Processor, Audio ADC, and so on.

- PVR section TPN-II performing PCI I/F and TP De-Mux, Memory, MPEG-II Encoder, IDE I/F Chip, and 120GB HDD.

- Video/Audio input section CVBS Decoder, and Audio processor

-1394 section

1394 1-Chip supporting D-VHS and MV Camcoder.

- Tuner It can receive a signal from ATSC/NTSC/Cable, and send a signal from the ATSC as TP, an analog video signal as NTSC, and an audio signal as SIF.

- Front section It is located at the front receiving various key inputs from users and displaying the status of a set-top box at the VFD.

- Power section It supplies a DC power to Main Digital Board, Front Board, and HDD with the input of AC 110V.

1-3

IMPORTANT SAFETY NOTICE

This manual was prepared for use only by properly trained audio-video service technicians.

When servicing this product, under no circumstances should the original design be modified or altered without permission from Zenith Electronics Corporation. All components should be replaced only with types identical to those in the original circuit and their physical location, wiring and lead dress must conform to original layout upon completion of repairs.

Special components are also used to prevent x-radiation, shock and fire hazard. These components are indicated by the letter “x” included in their component designators and are required to maintain safe performance. No deviations are allowed without prior approval by Zenith Electronics Corporation.

Circuit diagrams may occasionally differ from the actual circuit used. This way, implementation of the latest safety and performance improvement changes into the set is not delayed until the new service literature is printed.

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 property damage or user injury.

Service work should be performed only after you are thoroughly familiar with these safety checks and servicing guidelines.

GRAPHIC SYMBOLS

The exclamation point within an equilateral triangle is intended to alert the service personnel to important safety information in the service literature.

The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the service personnel to the presence of noninsulated “dangerous voltage” that may be of sufficient magnitude to constitute a risk of electric shock.

The pictorial representation of a fuse and its rating within an equilateral triangle is intended to convey to the service personnel the following fuse replacement caution notice:

CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE, REPLACE ALL FUSES WITH THE SAME TYPE AND RATING AS MARKED NEAR EACH FUSE.

SERVICE INFORMATION

While servicing, use an isolation transformer for protection from AC line shock. After the original service problem has been corrected, make a check of the following:

FIRE AND SHOCK HAZARD

1. Be sure that all components are positioned to avoid a possibility of adjacent component shorts. This is especially important on items trans-ported to and from the repair shop.

2. Verify that all protective devices such as insulators, barriers, covers, shields, strain reliefs, power supply cords, and other hardware have been reinstalled per the 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 or damaged insulation (including the AC cord), and replace if necessary.

5. No lead or component should touch a high current device or a resistor rated at 1 watt or more. Lead tension around protruding metal surfaces must be avoided.

6. After reassembly of the set, always perform an AC leakage test on all exposed metallic parts of the cabinet (the channel selector knobs, antenna terminals, handle and screws) to be sure that set is safe to operate without danger of electrical shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS TEST. Use an AC 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 150V AC type capacitor between a known good earth ground water pipe, conduit, etc.) and the exposed metallic parts, one at a time. Measure the AC voltage across the combination of 1500 ohm resistor and .15 mfd capacitor. Reverse the AC plug by using a non-polarized adaptor and repeat AC voltage measurements for each exposed metallic part. Voltage measured must not exceed 0.75 volts RMS. This corresponds to 0.5 milliamp AC. Any value exceeding this limit constitutes a potential shock hazard and must be corrected immediately.

TIPS ON PROPER INSTALLATION

1. Never install any receiver in a closed-in recess, cubbyhole, or closely fitting shelf space over, or close to, a 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 placement where draperies may obstruct venting. The customer should also avoid the use of decorative scarves or other coverings that 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 tests on customized installations.

5. Caution customers against mounting a product on a sloping shelf or in a tilted position, unless the receiver is properly secured.

6. A product on a roll-about cart should be stable in 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 using extension cords. Explain that a forest of extensions, sprouting from a single outlet, can lead to disastrous consequences to home and family.

A.C. Voltmeter

1500 OHM

10 WATT

Place this probe on each exposed metal part.

Good Earth Ground such as the Water Pipe, Conduit, etc.

0.15uF

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS

1-4

SERVICING PRECAUTIONS

CAUTION: Before servicing the HD/SD PERSONAL VIDEO RECORDER & RECEIVER WITH GEMSTAR 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. Remember Safety First:

General Servicing Precautions

1. Always unplug the HD/SD PERSONAL VIDEO

RECORDER & RECEIVER WITH GEMSTAR AC power cord from the AC power source before: (1) Removing or reinstalling any component, circuit board,

module, or any other assembly.

(2) Disconnecting 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 HD/SD PERSON-

AL VIDEO RECORDER & RECEIVER WITH GEMSTAR 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

which instruments covered by this service manual might be equipped.

5. Do not apply AC power to this HD/SD PERSONAL VIDEO

RECORDER & RECEIVER WITH GEMSTAR and / or any of its electrical assemblies unless all solid-state device heat sinks are correctly installed.

6. Always connect the test instrument ground lead to an

appropriate ground before connecting 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 include 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 grounded-tip soldering iron to solder or unsolder ES devices.

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

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

6. Do not remove a replacement ES device from its protective 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

♦ CPU [PPC405GP Rev E]

• PowerPC405GP, 32-bit, 200MHz RISC Processor

• I Cache 16K, D Cache 8K

• SDRAM Controller(100MHz speed)

• External Peripheral Bus(up to 8 device)

• PCI 2.2 I/F(32-bit, 33MHz)]

• DMA, Interrupt Controller, Serial Port, GPIO, I2C

♦ System Memory

• Main Memory : 32MB(K4S281632 x2)

• Flash Memory : 8MB(MEM29DL323x2)

• NVRAM : EEPROM(32KB, 105 Read/Write)

• Probe ROM : 512KB (Am29LV040)

♦ MPEG 2 A/V Decoder [LGDT1102A]

• 1 HD(MP@HL) or 4 SD(MP@ML)

• ATSC all format Decoding

• Memory : SDRAM 32MB(K4S641632 x4)

• Graphics

• 2D Graphics

• HD Resolution(max. 1080x1920 x16-bit)

• BitBLT/Rendering Cursor Support(by H/W)

• Alpha Blending(6-bit level) Support

• Audio Decoder

• AC-3 Decoding

• MPEG Audio Layer 1, 2 Decoding

• SPDIF Output

♦ PLL IC [LGDT1901A]

• HD-2 Video Clock Generation

• 27MHz VCXO input & Control Signals

♦ System CPLD [EPM7256AETC]

• HD-2 I/F Signal

• Address Decode

• GPIO

♦ Audio Processor [MSP4450]

• SIF Processing

• Audio Input Selection

• ADC/DAC

• Volume control

♦ Video Decoder [VPX3226F]

• CVBS Decoding

• Video Processing

• 656 Data Output

• VBI/CC support

♦ DVI Transmitter [Sil170]

• DVI output

• HDCP Support

♦ I2C Controller [PCF8584]

• Tuner(ATSC/NTSC/Cable) I/F

• Gemstar I/F

• Front MiCOM I/F

♦ TPN-II

• TP Processing for PVR

• PCI I/F

• SDRAM I/F 16MB(K4S641632)

• PVR Function

♦ MPEG-2 Encoder [BCM7040]

• MPEG-2 Encoding (MP@ML)

• 656/I2S Input, TP output

• SDRAM I/F 16MB(K4S643232)

• PCI I/F

♦ E-IDE Controller [ARS0303D]

• PCI I/F

• E-IDE Controller

♦ ATSC/NTSC/CableTuner[TDVL-H100P]

• AT/NT/Cable NIM Tuner

• I2C I/F, TP/CVBS/SIF Out

♦ Miscellaneous

• RS-232C

• RF Switch

• MiCOM( Timer, Gemstar Tuning)

• Gemstar I/F : Video Input, I2C

♦ IEEE-1394[TSB43CA42]

• 1394 TP In/Out

• Link&PHY(1-Chip)

♦ MUX CPLD [EPM7256AETC]

• 1394 TP In/Out

• Encoder TP, VSB TP, TPN-II TP In/Out

♦Gemstar Board

• GS501 : Gemstar Processor

• GS502 : AD Converter

• G-Link

♦ Power Board

• Input: AC120V/60Hz

• Output

- Main Board : 9V,5V,3.3V,L_5V,L_33V

- Front Board : -28V,-24V,-21.5V

- HDD : 12V, 5V

♦ HDD

• 120GB

• Ultra DMA-100

♦ Front Panel

• I2C I/F, Power On/Off

• VFD Display

♦ Remote Controller

• Basic TV

• PVR Function

System Specifications

1-6

♦ Input

• Antenna In : Terrestrial [F Connector]

• Antenna In : Cable [F Connector]

• CVBS Video/Audio-1 [RCA Jack, 3EA]

♦ Output

• Video Out

- Component Out : YPbPr [RCA Jack, 3EA]

- Composite Out : CVB S-1 [RCA Jack, 1EA]

- S-Video Out [Mini DIN Jack, 1EA]

• Composite Out : CVBS-2 [RCA Jack, 1EA]

• RGB Out : VGA [D-SUB 15-P, 1EA]

• DVI Out

• Audio Out

- Stereo Out -1 [RCA Jack, 2EA]

- Stereo Out-2 [RCA Jack, 2EA]

- SPDIF Out : Photo Link

• Serial Port

• IEEE-1394 Port [1394 2EA]

♦ G-Link

• S/W Up-grade

• IR Blaster

♦ Input

• AC120V/60Hz

♦ Output

• Main Board : 9V,5V,3.3V,L_5V,L_33V

• Front Board : -28V,-24V,-21.5V

• HDD : 12V, 5V

♦ Power Consumption : 35W

♦ Main Board Size

• 213(D) x317(W) with Dummy[Unit : mm]

• 170(D) x317(W) [Unit : mm]

♦ Gemstar Board Size

• 130(D) x48(W) [Unit: mm]

♦ Power Board Size

• 247(D) x 93(W) [Unit: mm]

♦ Front Panel Board Size

• 50(D) x 280(W) [Unit: mm]

♦ 430(W) x 69(H) x 297(D) [Unit: mm]

♦ 55(W) x 240(H) x 35(D) [Unit: mm]

In/out Connector Set-Top Box Size

Remote Controller Size

Power

Board Size

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

BCD

NOTE) Refer to “SECTION 4 REPLACEMENT

PARTS LIST” in order to look for the part number of each part.

250

467

A46

471

472

468

A47

467

273

272

271

465

A48

467

471

472

262

263

275

274

320

264

468

469

261

A44

261

330

261

266

465

261

467

A48A

471

467

471

A48B

266

465

2-3

2. Packing Accessory Section

INSTRUCTION ASSEMBLY

PACKING (RF)

BAG

CABLE

PACKING (LF)

BOX CARTON

806

804

803

801

802

803

822

D-SUB(RS23)

823

D-SUB(RGB)

3-1

SECTION 3

ELECTRICAL

CONTENTS

ELECTRICAL TROUBLESHOOTING GUIDE ..................................................................................................3-2

1. CPU(SYSTEM CONTROL) TROUBLESHOOTING.................................................................................3-2

2. ATSC/QAM FRONT_END TROUBLESHOOTING.................................................................................3-10

3. NTSC/FRONT_END TROUBLESHOOTING..........................................................................................3-12

4. VIDEO TROUBLESHOOTING ...............................................................................................................3-13

5. DVI TROUBLESHOOTING ....................................................................................................................3-22

6. AUDIO TROUBLESHOOTING ...............................................................................................................3-26

BLOCK DIAGRAM ..........................................................................................................................................3-33

1. OVERALL BLOCK DIAGRAM 1............................................................................................................3-33

2. OVERALL BLOCK DIAGRAM 2............................................................................................................3-34

CIRCUIT DIAGRAMS ......................................................................................................................................3-35

1. CPU & SYSTEM MEMORY CIRCUIT DIAGRAM..................................................................................3-35

2. CPU PERI & IR-IN & AUX-CTRL CIRCUIT DIAGRAM.........................................................................3-37

3. TERRESTRIAL FRONT_END CIRCUIT DIAGRAM .............................................................................3-39

4. HD2 & SDRAM CIRCUIT DIAGRAM .....................................................................................................3-41

5. DVI TRANSMITTER CIRCUIT DIAGRAM .............................................................................................3-43

6. VDP I/F & DISPLAY OUTPUT CIRCUIT DIAGRAM..............................................................................3-45

7. NTSC AUDIO PROCESSOR CIRCUIT DIAGRAM................................................................................3-47

8. POWER REGULATION CIRCUIT DIAGRAM ........................................................................................3-49

9. MPI CIRCUIT DIAGRAM........................................................................................................................3-51

10. PTC CIRCUIT DIAGRAM .....................................................................................................................3-53

11. BACK PLANE CIRCUIT DIAGRAM.....................................................................................................3-55

PRINTED CIRCUIT DIAGRAMS .....................................................................................................................3-57

1. DIGITAL MAIN PRINTED CIRCUIT DIAGRAMS(TOP).........................................................................3-57

2. DIGITAL MAIN PRINTED CIRCUIT DIAGRAMS(BOTTOM).................................................................3-59

3. MPI PRINTED CIRCUIT DIAGRAM(TOP) .............................................................................................3-61

4. PTC PRINTED CIRCUIT DIAGRAM ......................................................................................................3-63

5. BACK PLANE PRINTED CIRCUIT DIAGRAM......................................................................................3-65

3-2

ELECTRICAL TROUBLESHOOTING GUIDE

1. CPU(SYSTEM CONTROL) TROUBLESHOOTING

Start

Power is supplied normally?

YES

Clock signals are OK?

YES

Reset signals are OK at the time of power-on reset?

Chip selection signals are OK?

IIC channels are OK?

YES

Interrupt signals are OK?

Messages are output through RS-232C port on PC terminal?

END

YES

(B) Clock check

(A) Power check

(D) CS check

(E) IIC check

(F) Interrupt check

(G) RS-232C check

3-3

(A) Power check

2.5V is supplied to L101?

YES

3.3V is supplied to IC104(37), IC105(37), IC102(1), IC103(1), and IC201(3)?

YES

3.3V is supplied to IC106(14)?

(B) Clock check

25MHz clock is output from X101(3)?

Fig.01

YES

37.5MHz clock is input to IC201(87)?

Fig.02

3.6864MHz clock is output from X102(3)?

Fig.03

YES

Power Supply Check IC950(2) : 3.3V

Power Supply Check IC954(3) : 2.5V

Power Supply Check IC950(2) : 3.3V

Check X101

Check IC101 & IC201

Check X102

3-4

Fig.01 X101(3) : 25MHz CPU Clock

Fig.02 IC201(87) : 37.5MHz PERI Clock

Fig.03 X102(3) : 3.6864MHz UART Clock

3-5

IC107(3) is reset?

YES

IC106(4) is reset? Fig.04

YES

IC201(29, 56, 61, 64, 75) are reset?

YES

Check IC106

Check IC107

Check IC101 & 201

Fig.04 IC106(4) : Reset signal

3-6

(D) CS check

Logic low pulse is seen at R138?

Fig.05

YES

Logic low pulse is seen at R140?

YES

Logic low pulse is seen at R144?

YES

Check IC101, IC211

Check IC101, 104, 105

Check IC101, IC400

Logic low pulse is seen at R143?

YES

Check IC101, IC201

Fig.05 R138(1) : Flash CS signal

3-7

(E) IIC check

IIC SDA and SCL signals are output from IC211(19 & 18)? Fig.06 & Fig.07

YES

IIC SCL and SDA signals are output

from IC101(W17 & U15)?

YES

Check IC101

Check IC211

Fig.06 IC211(19) :

3.3V IIC SDA signal

Fig.07 IC211(18) :

3.3V IIC SCL signal

3-8

(F) Interrupt check

Logic high is input to IC101(D18) or R418?

YES

Logic high is input to IC101(W20) or CN201(7)?

YES

Check IC100, CN201(7)

Check IC100, IC400

Fig.08 IC101(D18) :

No Interrupt signal

3-9

(G) RS-232C check

RS-232C port setup is OK? (Baudrate, Parity, Data Bit, Stop Bit)

YES

IC204(10) is OK?(TxD signal)

Fig.09

YES

Check IC101, IC204

IC204(9) is OK?(RxD signal)

Fig.10

YES

Check IC101, IC204

Modify RS-232C port setup

Fig.09 IC204(10) : TxD signal

Fig.10 IC204(9) : RxD signal

3-10

2. ATSC/QAM FRONT_END TROUBLESHOOTING

Start

Power is supplied normally(TU300)?

YES

RF signal is detected?

(using Spectrum Analyzer)

YES

Check error signal(TU300(22)). (using Oscilloscope) High:normal, Low:Error

Check NIM Tuner(TU300)’s output signals of DATA(Fig.01) (pin 28,29,30,31,32,33,34,35), packet clock(Fig.02)(pin 27) and Byte clock(pin 36)(Fig.03).

END

YES

Check antenna connection.

Check the power lines(A9V, D5V_2, D3.3V_2, P_30V_TU) referring the circuit diagram.

Check the Voltage between L303 and Ground. 5V : normal, 0~4V : change Q300.

Check the status of connection on PCB. Change TU300.

3-11

FIG.01

TU300(28,29,30,31,32,33,34,35)

VSB/QAM DATA Outputs

FIG.02

TU300(27)

VSB/QAM DATA Packet Clock

FIG.03

TU300(36)

VSB/QAM DATA Byte Clock

3-12

3. NTSC/FRONT_END TROUBLESHOOTING

Start

Power is supplied normally?

YES

RF signal is detected?

(using Spectrum Analyzer)

YES

What Voltage is between L303 and ground ?

5V : NO 1V( below) : YES

Check NIM Tuner(TU300)’s output signal of VIDEO_OUT(pin 16, Fig.04).

END

YES

Check antenna connection.

Check the power lines(A9V, D5V_2, D3.3V_2, P_30V_TU) referring the circuit diagram

Change Q300.

Change TU300.

FIG.04

TU300(16) NTSC VIDEO OUT

4. VIDEO TROUBLESHOOTING

Start

No HV sync OUT?

YES

Any problem in OSD ?

YES

Any problem in main picture?

Any problem in AV out?

END

YES

(B)

(A)

What is the main picture source?

DTV or NTSC.

(C1)

(D)

DTV

(C2)

NTSC

3-14

(A)

Power is supplied to IC400[HD2]?

YES

Video display clock(IC600(7)) is supplied

to HD2? FIG.01

YES

Change Display Color select switch to RGB/DVI side and check HV sync. Any problem ?

END

YES

Check IC605(5) and IC600(1)

FIG.02.

Check L400( 1.8V), IC950(2) (3.3V).

Check IC605(1,8) and X600

if there is sinusoidal 27MHz clock. FIG.03

If HV sync exists in IC607 (6,7) (FIG.04)(FIG.05) then check IC607(1) is low. If not, check IC201(52).

FIG.01 VDP clock

3-15

FIG.02 VCXO 27MHz clock FIG.03 Crystal 27MHz clock

FIG.04 H-sync signal FIG.05 V-sync signal

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