26441030 training manual

8/13/2019 26441030 Training Manual

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Training Manual

Multi-Product Hi-Fi Technology and Troubleshooting

Course: A-124

Digital Board Hi-Fi OutputModel: STR-DE845 Troubleshooting

Switching Power Supply Super Audio CDModel: DAV-700/900 New Technology

DAV-S500HCD-S500HCD-C700/900

S


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Table of Contents

1. Introduction ..................................... 1

Purpose ............................................................1

Receiver ...........................................................1

Layout ..............................................................12. Sound Fields.................................... 2

What is a Sound Field? ....................................2

Sound Field Types............................................2

Virtual ...............................................................3

Cinema Studio ..................................................6

Semi Cinema Studio.........................................6

Theater .............................................................6

Music ................................................................6

Active Speaker Chart .......................................7

Table 2-1 - Input Software Format ....................9

3. Digital Board Inputs ....................... 10

Analog Inputs ..................................................10

Digital Inputs....................................................10

Software Formats Illustrated ...........................12

4. Control Signal Block ...................... 14

Input/Output Select ICs

Control Signal Block ........................................14

Digital Processing ICs

Control Signal Block ........................................15

5. Analog signal Block ....................... 19

Circuit Description ...........................................21

6. Digital Signal Block........................ 23

7. Mute Signal Block .......................... 25

8. Troubleshooting Block .................. 26

9. DAV-C700 Switching TypePower Supply...................................... 28

Safety for You and the Circuit ..........................28

Power Supply Operation .................................28

Regulation .......................................................32

How to Troubleshoot the Power Supply ..........33

Testing the Power Supply Unloaded ...............35

Troubleshooting Shortcuts ..............................36

10. Hi-Fi Output TroubleshootingOverview ............................................. 37

11. Troubleshooting DriverAmplifier & Bias Network Circuits .... 39

Protection light will not go off after replacingOutput transistors ............................................39

Excessive Current Draw ..................................40

12. Troubleshooting Audio

Protection Circuits ............................. 43(+/-) Offset Protection Circuit...........................44

Over Current Protection Circuit .......................45

13. Super Audio CD ............................ 46

Overview .........................................................46

The New Format for the Age ofDigital Pure Audio ............................................46

The DSD Format: No Data Deciminationor Interpolation Required .................................48

Delta Signal Modulation and A/D Converter ....49

Disc Features and Watermark Technology .....53

Appendix:

Individual ICFunctional Description ....................... i

IC1201 System Control .................................... i

IC1101 Digital Audio I/F Receiver (DIR) ........... i

IC1301 Digital Audio Decoder (DAD) ............... i

IC1401 Audio DSP ........................................... i

IC1503 Audio Codec ........................................ i

IC1403 SRAM (Static RAM) ............................. i


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1. Introduction

Introduction

Purpose

The focus of this book is on the digital board operation in the sample receiver (STR-DE845) and covers thefollowing subjects:

A working understanding of sound fields and what type of movie or music software should be used witheach sound field for optimal performance.

Proper use of the digital board inputs.

Which speakers receive actual audio while in various sound field modes.

Simplified circuit diagram and operation of the digital board for troubleshooting.

To properly troubleshoot the Digital board, a good understanding of what sound fields are and how they affectthe input is essential. Once a good working knowledge of sound fields is obtained, the receiver can be better setup to process the movie or music software for the best quality audio output. The information in this book will alsohelp the technician determine whether a customers problem is a receiver setup or an actual circuit defect.

Receiver

The main receiver used for demonstration throughout this book is the STR-DE845. The STR-V444ES digitaboard will also be covered, showing the DSP circuit changes as compared to the STR-DE845 only. The overaloperation of the digital board in both models is the same.

Layout

Chapter 2 covers the theory and functional description of the various sound fields. Chapter 3 illustrates theproper use of the receiver (digital board) inputs on the rear panel. Chapters 4, 5, 6 and 7 provide the technicianwith block diagram descriptions of the four main systems found on the digital board. Chapter 8 describes a verypractical troubleshooting method for determining a defective component on the digital board. There is also anappendix at the end of the manual that provides a brief description of the function of the main ICs on the digitaboard.


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2. Sound F ield

Sound Fields

Dire

ctSoundwave

Early

Soundwav

e

Reflec

tion

LateSoundwave

Reflection

FIGURE 2-1 - Soundwave Reflection Diagram

STAGE

What is a Sound Field?

Each venue, be it a concert hall, cinema theater or small jazz club, has a characteristic sound field made up of

direct sounds and reflections from the surfaces of the environment. Some venues sound large and spaciousothers sound small and intimate. These characteristics are captured using special microphone pickup systems

placed in the actual venue. The microphone pickup system captures the acoustic blue print of the venue, which

contains all of the acoustic information about the venue, such as direct sounds, early reflections and reverberations(reverberations occur when the number of reflected sound-waves arriving at the listeners ear becomes very

large; ref. Figure 2-1). All the acoustic data about the venue is stored in the computer and then downloaded tothe A/V receivers microprocessor internal memory. So when you select the concert hall sound field on your A/V

receiver, the information stored in the microprocessors internal memory is activated and your living room takes

on the characteristics of an actual concert hall.

Sound Field Types

Auto Format Decoding (press AFD button)

This mode automatically detects the type of audio signal (Software Format) being input (e.g. Dolby Digital, DolbyPro-Logic, or Standard 2 Channel Stereo) and performs the proper decoding if necessary. This mode presents

the sound as it was recorded/encoded, without adding any sound field effects.

NOTE: This mode can be used as a reference. Set the equalizer to OFF while using this mode to hear thesource sound exactly as it was recorded. This mode can also be used to determine exactly what type of Software

format is encoded on a given disc.

2 Channel (press 2CH button)

Outputs the sound from the front left and right speakers only. Standard two channel (stereo) sources completely

bypass the sound field processing. Multi-channel surround formats are down-mixed to two channels.

NOTE: No sound is output from the sub-woofer (LFE) when the 2 Channel mode is selected.

Normal Surround

This mode is designed to be used with a Multi-channel surround audio input (e.g. Dolby Digital/AC-3, DTS o

Dolby Prologic) and the normal six-speaker surround system (front left/right, rear left/right, center and LFE) (ref.Figure 2-2). When the playback material is encoded with multi-channel surround audio, it will be heard as it was

originally recorded (with no other processing for special effects). For example, a movie will be played backexactly how the producer recorded it during the movies production. If Dolby Prologic (2 channel audio) encode

material is input, it will be processed to create surround sound effects using the actual six-speaker system.


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2. Sound F ield

Note:

Front Left FLT

Low Frequency Effects - LFE

Center Cntr

Front Right FRT

Rear Left RLT

Rear Right - RRT

Listening Position LP

Virtual

The five different Virtual modes create sets of virtual speakers using the actual existing speaker system which

could be a six or three speaker system.

1) V. Multi Dimension: Uses 3D image processing to create four setsof virtual rear speakers surroundingand positioned at an elevation of 30 degrees higher then the listener from a six-speaker system (two

actual rear speakers). Depending upon where the actual rear speakers are positioned, the virtual speakerspositions will vary (ref. Figures. 2-3, 2-4 and 2-5). The position of the rear speakers (Side, Mid or Rear

must be programmed in the A/V receiver SET-UP menu for this sound field effect to work properly.

NOTE: The virtual speakers are placed at an elevation of 30 degrees higher then the listener to further

emulate the theater venue. The surround sound speakers in a theater are always higher then the listenersposition.

FIGURE 2-2

L RLFE

LS RS

C

FIGURE 2-3 - Rear Speakers Side

RCL

1

2

3 4

1

2

34

LFE

LSLS RS

FIGURE 2-4 - Rear Speakers Middle

RCL

2

1

3

LS

4

1

2

3

RS

4

LFE

FIGURE 2-5 - Rear Speakers Behind

RCL

2

1

3

4

LS

1

2

3

4

RS

LFE


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2. Sound F ield

FIGURE 2-6 - Rear Speakers Side

RCL

LS

1

2

3

RS

1

2

3

LFE

FIGURE 2-7 - Rear Speakers Middle

RCL

1

2

LS

3

1

2

RS

3

LFE

FIGURE 2-8 - Rear Speakers Behind

RCL

1

2

3

LS

1

2

3

RS

LFE

2) V. Multi Rear:Uses 3D image processing to create three setsof virtual speakers from a six-speaker

system (two actual rear speakers; ref. Figures. 2-6, 2-7 and 2-8). The position of the rear speakers (SideMid or Rear) must be programmed in the A/V receiver SET-UP menu for this sound field effect to work

properly. Note: No 30-degree higher effect.

3) V. Semi-M. Dimension: Uses 3D image processing to create five setsof virtual rear/surround speakerssurrounding and positioned at an elevation of 30 degrees higher then the listener. This is accomplished

using only the front left and right speakers without using actual rear speakers (ref. Figure 2-9).

FIGURE 2-9

2

1

3

4

5

1

2

3

4

5

RCL LFE

4) Virtual Enhanced A: Uses 3D image processing to create three sets of virtual rear/surround speakers

This is accomplished using only the front left and right speakers without using actual rear speakers (ref

Figure 2-10).


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2. Sound Fields

FIGURE 2-11

RCL

1 1

LFE

FIGURE 2-10

1

2

3

1

2

3

RCL LFE

5) Virtual Enhanced B: Uses 3D image processing to create one set of virtual rear speakers. This isaccomplished using only the front left and right speakers without using actual rear speakers (ref. Figure2-11).


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2. Sound Fields

FIGURE 2-12 - Listener, Actual and Virtual S eaker Setu

RCL LFE

2

1

3

4

5

1

2

3

4

5

Cinema Studio

This mode is designed to be used with a Multi-channel surround audio input (e.g. Dolby Digital/AC-3, DTS orDolby Prologic) and the normal six-speaker surround system (front left/right, rear left/right, center and subwoofer)Cinema Studio is similar to Normal Surround except now the acoustical characteristics of a Sony PicturesEntertainment cinema production studio are present. The 3D image processing of the V. Multi Dimension (avirtual speaker mode which will be discussed shortly) is added to the normal surround sound audio to producethe cinema studio atmosphere. There are three Cinema Studio sound fields:

1) Cinema Studio EX. A: Reproduces the sound characteristics of the Sony pictures Entertainment CaryGrant Theater cinema production studio. This sound field can be used when viewing almost any type omovie.

2) Cinema Studio EX. B: Reproduces the sound characteristics of the Sony pictures Entertainment KimNovak Theater cinema production studio. This sound field is ideal for viewing science fiction or actionmovies with lots of sound effects.

3) Cinema Studio EX. C: Reproduces the sound characteristics of the Sony pictures Entertainment scoringstage. This sound field is ideal for viewing musicals or classic films where music is featured in thesoundtrack.

Note: The Cary Grant and Kim Novak Studios are actual Sony Pictures Entertainment Movie Production Studios

where a movie is shot and produced. Each has its own unique acoustical characteristics, which in these caseseven have particular characteristics for certain types of movies (e.g. The Kim Novak Studio is particularly goodfor Science Fiction movies). The Sony Entertainment Scoring Stage is an actual studio used for recording themusic portion of the movie. Once again, this studio has especially good characteristics for recording moviesound tracks. This makes this mode particularly good for playing back certain movies where the sound track isa major part of the movie (e.g. a musical movie).

Note: These sound fields use the 3D sound imaging of V. Multi Dimension. Reference figures 2-3, 2-4 and 2-5for the three possible virtual speaker system positioning, which depends on the positioning of the two actual rearspeakers.

Semi Cinema Studio

These three sound fields (Semi Cinema Studio EX. A, Semi Cinema Studio EX. B and Semi Cinema StudioEX. C) are identical to the above Cinema Studio mode except now the Sony Picture Entertainment cinemaproduction studio sound characteristics are reproduced using only front left, right and center speakers. All othespeakers are virtual (ref. Figure 2-12).


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2. Sound F ield

Theater

There are four theater sound fields:

1) Night theater: Retains theater-like sound characteristics while listening at a low volume level, ideal forlate night movie viewing.

2) Mono Movie: Creates theater-like sound characteristics from movies with mono soundtracks.

3) Stereo Movie: Creates theater-like sound characteristics from movies with stereo soundtracks.

4) Headphone theater: Retains theater-like sound characteristics while listening through a pair of

headphones.

NOTE: Mono Movie and Stereo Movie modes do not convert input signals to Mono or Stereo signals.They are strictly used for optimal playback of analog 2ch movie soundtracks.

Music

Nine different sound fields reproduce the acoustical characteristics of nine different venues. Each one of thesesound fields is designed for a 2-channel stereo input (e.g. from a CD, DAT, TV Broadcast, etc.). Some of these

sound fields are designed to perform better with certain types of music (e.g. Jazz Club with Jazz, Rock music

with Live House and so on). These sound fields are listed below:

Small Hall Church

Large Hall Live House

Opera House Arena

Jazz Club Stadium

Disco Club

Video Games

Game: This sound field is designed to be used with video game software and a stereo input. This mode wil

produce dynamic audio while playing video games.

Active Speaker Chart

With so many sound fields and software formats, it can be very difficult to know which speakers are active (actuaaudio applied to them by the receiver) for the software while in a particular sound field mode. Chart 2-1 on the

following page shows Sound Fields on its vertical axis and Software Formats on the top horizontal axis. Itindicates which speakers are active with the chosen Sound Field and Software Format. This chart also indicates

when Virtual Speakers are present. To get the same results as this chart at any location, the following conditions

must be met:

Conditions

1) The input device (e.g. DVD, CD etc.) must be set up properly to output the desired Software Format (e.g

AC-3, DTS etc.).2) The proper input on the receiver must be used to receive the desired Software format.

a. Optical and Coax Inputs: Dolby Digital (AC-3), DTS, Dolby Prologic, Dolby Surround and PCM

b. Analog Inputs: Dolby Prologic, Dolby Surround, Stereo and Mono

c. 5.1 Channel Input: This input bypasses all surround sound processing of the receiver. Note

This is a good input to use to test if all the speakers in the system are receiving audio. The

input device must have a 5.1 Channel output.


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2. Sound Fields

3) Speaker wires must be connected correctly, e.g. the Positive (+) on the receiver terminal connected to thePositive terminal on the speaker. Same for the Negative (-) terminal.

4) The speaker impedance switch on the receiver should match the impedance of the speakers connectedNote: If only output A is used, the impedance switch should be set to match the speakerimpedance (e.g. 4 or 8 ohms). Caution!!! - If the A and B output are used simultaneously, theimpedance of each speaker must not be less then 8 ohms and the impedance switch must be setfor 4 ohms. This is because the speakers are placed in parallel when in this configuration so the

impedance of the speakers is cut in half.

Notes for Chart:

1) The box around the speaker letter indicates that this is an actual physical speaker (not virtual) andaudio is applied to the speaker.

2) There are notes under pictures to indicate if virtual speakers are being created.

NOTE: The actual rear surround sound speakers will be inactive in the following sound field modes:

Semi-Cinema Studio EX. A, B, and C

V. Semi-M Dimension

Virtual Enhanced A and B

2 Channel


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2. Sound Fields

Sound F ield

Normal SurroundL C R

S

L C R

S

L C R

S

Cinema S tudioEx. A, B, C

L C R LFE

LS R S

L C R LFE

LS R S

W ith addit ional vir tualspeaker

L C R

S

L C R

S

L C R

S

Sem i-Cinema StudioEx. A, B, C

L C R LF E

Al l other speakersvirtual

L C R

Al l other spea kersvirtual

L C R


L C R

All other speakersvirtual

Night Theater L C R LFE

LS R S

L C R

S (reverb)

L C R

S

L C R

S

Mono M ov ie L C R LFE

LS R S

L C R

S

L R

S

L C R

S (reverb)

Stereo MovieL C R LFE

LS R S

L C R

S

L R

S

L C R

S (reverb)

V. Mult iD imension

L C R LF E

LS RS

W ith a ddi tional

vir tual speakers

L C R

S

L C R

S

L C R

S

V. Mu l ti RearL C R LFE

LS R S

W ith ad di tionalvir tual speakers

L C R

S

L C R

S

L C R

S

V. Sem i - MDimension

L C R


L C R


L C R


V i r tual Enhan cedA, B

L C R LFE


L C R

Al l other sp eakersvirtual

L C R

Al l other spe akersvirtual

L C R

Al l other spea kersvirtual

L C R LFE


Sm al l Hal lLarge Hal lOpera HouseJazz ClubDisco ClubChurchLive Hous eArenaStadiumG a m e

This table shows wh ich speakers are act ive dur ing a pa r t icular sound an d sof tware format input .

L C R LFE

LS R S

L C R

S

L R

S

L R

2 Channel L R L R L R L R

A.F.D.L C R

S

L R L RL C R LFE

LS R S

TABLE 2-1 - INPUT SOFTW ARE FORM AT

Dolby Digi tal (AC-3) 5.1 Chanel Surround D T S

D olby Pro log ic PC M Stereo M ono


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3. Digital Board Inputs

Digital Board Inputs

Analog Inputs

2 Channel Stereo Inputs

There are nine analog inputs on the digital board. They are as follows:

-

Tuner- Phono

- CD

- MD/Tape

- TV/SAT

- DVD/LD

- Video 1, 2, 3

These inputs enter the digital board as analog audio and supply one of the following audio formats: Mono, Stereoor Dolby Prologic. They go through a switching IC and then onto the Audio CODEC to be digitized. The digitadata stream is applied first to the Audio Decoder and then to the Audio DSP, which processes and applies the

effects of the chosen sound field.

5.1 Channel Input

The 5.1 Channel Input is a full surround sound analog audio input that bypasses the sound field processing ofthe digital board in the receiver. All the surround sound processing required to produce the 5.1 Channel Input isperformed by the device connected to this input, such as a DVD player with a 5.1 Channel Output. The 5.1Channel Input is applied directly to the output selector IC1502. IC1502s outputs are connected directly to theamplifier system. The 5.1 Channel Input actual consists of six signals: Front Left, Front Right, Rear Left, ReaRight, Center and Subwoofer. The Subwoofer is the 1 in the 5.1 designation.

Digital Inputs

There are two types of digital inputs - the Optical input and the Coaxial input. The only difference between these

two inputs is the medium used to transfer the signal between devices. The Optical input utilizes Fiber Optic cableto transmit data as light pulses down a glass fiber center conductor. Because light pulses are used, the FibeOptic cable is virtually immune to any external electrical interference, making it the preferred digital signal sourceThe Coaxial Input uses Coaxial cable similar to that found in Cable TV connections. It consists of a coppecenter conductor, a foam insulator and an outer braided wire shield. The Coaxial cable has good external noiseimmunity characteristics, but cannot compare to the Fiber Optic cable. Also, the bandwidth characteristic of theFiber Optic cable is much greater. Both of these input types are digital, using the same data protocol (S/P DIFformat). There are three Optical inputs, one Optical Output and one Coaxial input on this receiver.

Optical: Coaxial:

DVD/LD input DVD/LD

TV/SAT input

DAT/MD input

MD/DAT output


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COAXANTENNA

FRONTREAR

CENTERL

R

DEVICESDVDMULTI-CHANNEL DECODENOTE: THE DEVICE MUST BE CAPABLE OFPROCESSING AC-3,OR DTS SOFTWARE ANDOUTPUT 5.1 CHANNEL SIGNALS

ANALOG

INPUTS

VCRPHONO CD MD/DAT TAPETV/SAT

DVD/LD VCR DEVICES

DOLBY SURROUND DOLBY PROLOGIC STEREO MONO

SOFTWAREFORMATS

ANALOGINPUTS

AM

SIGNALGND

5.1 CH INPUTSUB

WOOF.

CTR SIN S-VIDEO

OUT

FRONT REAR CENT.

VIDEOOUT

MONITOR

OPTICAL

VIDEO IN CONTROL AII

DIGITAL

+

-

R

2ND AUDIO

OUT

MD/DATOUT

MD/DAT

IN TV/SATIN

DVD/LDIN

DVD/LD IN

B

S-VIDEOOUT

S-VIDEOIN

VIDEOIN

VIDEOIN

VIDEO OUT VIDEOOUT

VIDEO IN

L

R

IN IN OUT IN OUT IN A IN A IN AUDIO OUT A IN AUDIO OUT IN

S-VIDEOIN

S-VIDEOIN

CTR SSTAT.IN

CTR SOUT

CTR SOUT

L

R

STR-DE845(REARVIEW)

DIPOLE

WIREANTENNA

FIGURE 3-1 - STR-DE845 ANALOG & DIDITAL INPUTS

COAXIAL

FM75

DEVICESMD/DATTV/SAT

SOFTWAREFORMATSDOLBY DIGITALAC-3 (5.1)DTS (5.1)DOLBY PROLOGIC

PCM 48kHz, 41.1kHz,32kHz

DVD/LDDVD/LD(COAX)

SOFTWAREFORMATSDOLBY DIGITALAC-3 (5.1)DTS (5.1)DOLBY PROLOGICPCM 96kHz, 48kHz,41.1kHz, 32kHz

DEVICES

DIGITAL INPUTS

SUBWOOF

IMPED

SPEAKERS

10/15/0113CA124 1380

Table 3-1 Digital Input Sampling Frequency Compatibility

Input Sampling Frequency

Optical DVD/LD 96KHz, 48KHz, 44.1KHz, 32KHz

Optical TV/SAT 48KHz, 44.1Khz, 32KHz

Optical DAT/MD 48KHz, 44.1Khz, 32KHz

Coaxial DVD/LD 96KHz, 48KHz, 44.1KHz, 32KHzNOTE: If a signal with a sampling rate of 96kHZ is applied to the MD/DAT or TV/SAT inputs, intermittentaudio at the receiver outputs may occur.

These digital inputs are sent through the complete surround sound processing circuitry of the digital board toproduce the 5.1 Channel Output signals. This processing and signal flow will be discussed in detail in the nexchapter.


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FIGURE 3-2

S

S

R

C

L

FourChannelSignals

DolbySurroundProLogicEncoder

Software Medium Laser Disk DVD Disk CD VHS Tape Cassette Tape Cable Satellite TV Regular Tv

Left

Right

Center

Surround

DolbySurroundProLogicDecoder

LT

RT

LT

RT

Note: From a live performance or recording

DOLBY SURROUND PROLOGIC

DigitalDataStream

FIGURE 3-3

R

C

L

5.1ChannelSignals

DolbyDigitalorDTSEncoder

Software Medium Laser Disk DVD Cable

Satellite TV Regular TV

Left

Right

Center

LeftSurround

DolbyDigitalorDTSDecoder

Note: From a live performanceor recording

RightSurroundLowFreq.Effect

DigitalDataStream

LFE

LS

RS

DOLBY DIGITAL & DTS

Figure 3-1 illustrates the typical devices connected to the various receiver inputs and what software formats arecompatible with each input.

NOTE: The audio from the Tuner antenna section is also an input to the digital board. It is processed the sameas any of the other analog inputs in order to apply the desired sound field effects. The input signals to the tuneare off the air (FM and AM) signals. There is also an analog Video 3 Input on the front panel of the receiver thacan accommodate another VCR.

Software Formats Illustrated

Dolby Surround Prologic

Figure 3-2 illustrates the encoding and decoding of a Dolby Surround Prologic format. Note that this format canbe encoded on the software medium (DVD disk, VHS tape etc.) in a digital data stream or analog signal. Theoriginal four channels are encoded into two channels (Left Total and Right Total). At the decoder, the twochannel signal is decoded back to the original four channel surround signals (Left, Right, Center and Surround)Also note that the surround signal in the Prologic format in fed to both rear speakers, so both speakers receive

equal signals. There is a slight delay in time as compared to the front speakers.

Dolby Digital (AC-3), and DTS


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3. Digital Board I nput

FIGURE 3-4 - 5.1 Channel Downmixing

LC

R

LS

RS

LFE

LT

RT

L

R

Decoder "A"

Decoder "B"

Decoder "C"

Decoder "D"

Dolby Digital

or

DTS 5.1 ChannelData Stream

Dolby

Prologic

Decoder

LC

R

S

5.1 Channel

Signals

Two Channel

Stereo Signals

Mono Signal

Four Channel

Dolby Surround

signals

Figure 3-3 illustrates the encoding and decoding Dolby Digital and DTS 5.1 channel formats. These formats are

encoded into a digital data stream only, such as a DVD disc, Satellite signal, etc. (no analog encoding). Thereare actually six channels in the 5.1 channel format (Left, Right, Center, Subwoofer or LFE, Left surround and

Right surround). Note that the rear speakers are now fed totally separate surround signals that provide asuperior separation between the speakers when sounds are traveling around the system. Also added to this

format is the Low Frequency Effects (LFE) or Subwoofer signal.

5.1 Channel format compatibility

Figure 3-4 illustrates that the 5.1 Channel format is compatible with all of the other formats. The 5.1 channesignal as shown can be DOWN-MIXED into any other format depending on the decoding applied. This is simila

to the Prologic format, which is compatible with stereo and mono system due to the way it is encoded.

New Development in Digital Surround Technology

Dolby Digital Surround EX (6.1)

FIGURE 3-5Dolby Digital; EX (6.1)

RCL

LS RS

LFE

CS

A center screen channel (or speaker) is necessary to ensure the precise localization of the front sounds for theviewers. Dolby Digital Surround EX brings similar benefits to the surround sound field (side or rear speakers)

With Dolby Digital Surround EX, a center surround channel is reproduced. This speaker driven by the centesurround channel is positioned at the back/center of the listening room. Left and right surround sound is stil

reproduced by the side speakers (Ref. Fig. 3-5). This means that sounds can now be positioned behind the

audience, opening the door to exciting new effects such as true 360-degree pans. The center surround channealso makes front-to-back and back-to-front transitions more realistic. Dolby Digital Surround EX is fully compatible

with the current 5.1 Channel digital formats, and will play back normally on current 5.1 systems. Dolby DigitaSurround EX basically adds a center surround channel to 5.1 digital formats.


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4. Control Signal Block

Control Signal Block

Input/Output Select ICs Control Signal Block

IC303ANALOG

INPUTSELECT

12

IC301ANALOG

INPUT

SELECT

15 16

3 5 4

15 14 16

IC1005DIGITALINPUT

SELECT

2 14

7

17TO

IC304/PINS 3

& 5

19 17 18

47 48 46

93 92

2 CH. MODEFROM IC304

CLK

CE

SDI

L R

SDI14

CLK

CE

SDI CLK CE

A B

R1007

R1006

ANALOGINPUTSREARPANELJACKS

12 17

L

R

TOIC1101/PIN 3

ANALOG INPUTSREAR PANEL

JACKS

SD I CLK CE

R1282 R1281

EXTERNAL5.1 CH.J307

5.1 CH.INPUTFROMIC1503

TO IC304/PINS 3 & 5

CNP301

CNS306

CNS5

A B

DIGITALINPUTSFROM

X120116MHz

IC1201SYSTEM CONTROL

107108

FIGURE 4-1DIGITAL BOARDINPUT/OUTPUTSELECTOR ICs

CONTROL BLOCK

1A124 1365 11/20/01

IC1001IC1002IC1003

J1001

OPTICAL

COAXIAL

IC1502OUTPUTSELECT

15 14 16

19 AC 18

IC1005 CONTROL LINES

PIN No.

(OPTICAL) DVD/LD

(OPTICAL)TV/SAT

(OPTICAL)DAT/MD

(COAX) DVD/LD

A2

B14

0

1 0

0 1

1 1

0

TABLE 4-1

DIGITAL BO ARDMAIN BOARD

AU SW BOARD

2 1 3 CNP11

DIGITAL BOARD

Circuit description

NOTE: Reference Figure 4-1 for the following circuit description:

Data, Clock and Chip Enable Lines

All control signals are supplied by IC1201 (System Control). IC1201/Pins 108 and 107 control the digital inpuselection of IC1005 (pins 2 and 14). These control lines are a simple two-bit input. Table 4-1 shows the two-bicode for the corresponding input. The resistors on the output of IC1201 (R1282 and R1281) and on the input oIC1005 (R1006 and R1007) are easy probe points to confirm the bit pairs in the table.

The control lines for IC301, IC303 (analog input select ICs) and IC1502 (output select IC) are at IC1201/pins 46(CE), 47 (Data) and 48 (CLK). These control signals are somewhat difficult to view due the fact that they are onlypresent while switching between inputs via the front panel buttons of the receiver. However, the main concernhere is that there is communications between ICs and that the actual inputs do change. Waveforms 4-1, 4-2 and4-3 illustrate how the waveforms will appear on the oscilloscope while switching between inputs (e.g. Video 1,Video2, DVD/LD etc). Once again, these are not exact waveforms. Confirmation of data communicationsbetween ICs and data amplitude (5Vpp) are the important factors. All three pins (IC1201/46, 47 and 48) are at alow state (0V) while waiting for a button to be pressed (standby state).


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16

4. Control Signal Bl ock

WAVEFORM 4-4

DATA

CLK

CE

WAVEFORM 4-5

DATA

CLK

CE

Oscilloscope Settings:

5V/div.

100us/div or 50us/div

Trigger rising edge


5V/div.

2us and 200ns/div

Trigger rising edge

Circuit Description

Data, Clock, and Chip Enable Lines

The control lines for IC1401 (IC1201/parallel data lines 17 to 24, pin 25 (address line) and pin 16 (CE)) and

IC1503 (IC1201/pins 30 (data), 29 (CLK) and 28 (CE)) are only present during input switching. The waveforms

on the control lines are the same as those shown in Waveforms 4-1, 4-2 and 4-3, exceptstandby voltage stateis high (5V dc).

The waveforms on the control lines for IC1101 (IC1201/pins 112 (data), 110 (CLK), and 111 (CE)), and IC1301(IC1201/pins 1 (CLK), 2 (data), and 3 (CE)) are always present as digital data is present at one of the digital inpujacks (optical or coax). Waveforms 4-4 and 4-5 illustrate what is displayed on the oscilloscope. When the Inpu

mode is set to Analog input, all three control lines on IC1101 are inactive and the chip select line on IC1301 is

inactive (the other two lines on IC1301 are active with data, but the chip is not enabled).

The following waveforms can be viewed on the oscilloscope continuously when digital data is present at thedigital inputs andthat digital input is selected.

Master, Bit and Left/Right Channel Clock lines

All the control lines discussed so far are used either for input/output switching or to set up an IC for a particulafunction (e.g. Dolby Digital decoding). The Clock lines that will be looked at now are used for data manipulation

The Clock lines MCLK (Master Clock), BCLK (Bit Clock) and LRCLK (Left Right channel Clock) are all developedby IC1101 using X3501 (12.282MHz). The MCLK is applied only to IC1503 (CODEC), while BCLK and LRCLK

are applied to IC1301 and IC1503. These Clock lines are used to synchronize the system to the incoming audio

data stream so that appropriate decoding and coding can be performed. The following waveforms are alwayspresent and can be viewed easily with the oscilloscope. Waveform 4-7 is an expanded view of Waveform 4-6

The frequency for each clock signal is as follows:

MCLK 12.282MHz

BCLK 3MHz

LRCLK 48KHz

WAVEFORM 4-7

BCLK

LRCK

MCLK

WAVEFORM 4-6

BCLK

LRCK

MCLK

Data and Control Line Waveforms for IC1101


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SRAM Control Lines

Reset lines and Crystals

The main Reset line is applied to IC1201/pin 90. During normal operation, this line is High (5V dc).

The other Resets are output to IC1101/ pin 48 (normal high 5V), IC1301/pin 62 (normal high 5V), IC1503/pin 17(normal high 5V) and IC1401/pin 26. This output is Low (0V), but it passes through inverter IC1202 and a High

(5V) is applied to IC1401. The crystal frequencies and amplitudes are shown in Table 4-2 below:

Table 4-2 Crystal Frequencies and Amplitudes

IC Ref. Number Crystal Ref.Number

Frequency Amplitude

IC1101 & 1301 X3501 12.282MHz 4Vpp

IC1401 X1401 10MHz 3Vpp

IC1201 X1201 16Mhz 4Vpp

9/26/01

IC1402

SRAM

17

41

D0 - D3 7 - 10

D4 - D7 13 - 16

D8 - D11 20 - 32

D12 - D15 35 - 38

A0 - A4 5 - 1A5 - A7 44 - 42

A8 - A11 27 - 24

A12 - A15 21 - 18

WE

OE

IC1401

AUDIO

DSP

53

|69

53

|

69

74

70

XWE

XOE

FIGURE 4-3 - SRAM BLOCK

There are 16 Data, 16 Address and two control lines (WE and OE) for the SRAM IC1402.. The SRAM is mainlyused for the processing of the Cinema and Hall sound fields where reverberation (Delay) is required to produce

the appropriate characteristics of a particular venue. The SRAM IC1402 is not used in any of the Virtual SpeakeModes. All processing is performed by internal RAM in IC1401, so no data is present on either the Data, WE o

OE lines. Waveforms 4-8, 4-9 and 4-10 show the activity on the Data lines. WE and OE lines are in three

different modes: AFD, 2CH and Mode (sound field selection mode). The main point of interest of these three


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5V/div

10us/div

Trigger rising edge

WAVEFORM 4-8

WE

DATA

OE

WAVEFORM 4-9

WE

DATA

OE

WAVEFORM 4-10

WE

DATA

OE

waveforms is the amount of activity in each mode. The first two modes (AFD and 2CH) show very little activity

because no reverberation is necessary and all the processing is being performed in the DSP internal RAM. Thethird mode, where any of the Cinema studio and Hall modes can be selected, shows increased activity. Note

The Normal Surround mode does not use reverberation so when in this mode, the waveforms will look like theWaveforms 4-8 and 4-9. The increased data activity confirms that the DSP and the SRAM are attempting to

produce the selected sound field. This does not confirm that the data is good; further testing is necessary and

will be discussed in a later section.

Data and Control Line Waveforms for IC1402


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5. Analog Signal Block

Analog Signal Block

NOTE: In Figure 5-1, only the left channel signal flow is shown but the same signal flow can be used to trace theright channel analog signal through the same ICs except pin numbers are different. Also, all resistors shown onthis figure are surface mount components with easy probing points.

Test Disk: YEDS-18 Track 2 (1KHz signal)

Equipment: CD player connected to CD analog input jack.

or DVD player connected to DVD/LD analog input jack

Caution: The 1KHz test signal is good for signal tracing up to IC1301/pin 85. After this point, the signal outpuwill depend upon the sound field selected. For example, if Normal Surround mode is selected, only audio will bepresent on the center channel. This is because the 1kHz signal is equal in both the Left and Right channels. Iis detected as monaural and sent to the center channel. In other sound fields such as Cinema and Hall, thesystem sends certain amounts of the 1KHz signal to all speakers. Using the 1KHz signal for testing can help in

understanding how the various sound fields process signals as described in the Sound Field section of thiscourse. One important point to remember is that no LFE (subwoofer) channel will be present when using the1KHz signal. Track number 4 (100Hz signal) on the YEDS-18 disk can be used to produce signals on the LFEchannel. To fully test all channels on a sound field, a movie sound track or music should be used.

Troubleshooting all Signal Paths: The above procedure is good for signal tracing up to IC1301/pin 85. Thesignal path after IC1301 is broken into three separate lines (IC1301/pin 24 SOA, pin 23 SOB and pin 22 SOC)All three lines are digital data. To view data activity on all three lines, a DVD disc with Dolby Digital encodeinformation must be used for the audio source. For the following test procedure, the Dolby DVD Demo and TesDisc are is used.

Test Disc: Dolby Digital Test DVD version 1.5

Test CD Ordering Information:

TEAC AMERICA, INC.7733 Telegraph Road, Montebello, California 90640

Tel: 1-(323) 727-7643, Fax: 1-(323) 727-7612Email: [email protected]


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11/20/01

LEFT CHANNELFROM ANALOGINPUTSIC301, IC303

IC3046

57

C311

-+

C381

R391

CNP301

16 5

CNP11

1 CNP10

TO IC15022 CH.MODE INPUT

1CNP7

- +

- +

+

-

6

+-

IC1504R1522

C152229

30

R1524

R1526

23|

28

9

5.1 CHANNELOUTOUT TOIC1507,IC1506,IC1505

R155885

24

23

22

SDISOA

SOB

SOC

IC1301DIGITAL

DECODER

IC1403

4

5

3

117

118

119

R1303

R1304

R1305

R1450

R1451

R1452

2

3

4

6

7

8

R1401

R1402

R1403

53|

69

76

|94

DATA

ADDRESSSRAMIC1402

IC1401AUDIODSP

SIA

SIB

SIC

SOA

SOB

SOC

LIN-

LIN+

SDTOSDI 1

SDI 2

SDI 3

IC1503AUDIOCODEC

NOTE: ONLY LEFT CHANNEL IS SHOWN IN THIS DIAGRAM. THE RIGHT CHANNEL HAS AN IDENTICALSIGNAL PATH

FIGURE 5-1 - ANALOG SIGNAL BLOCK 5A124

6

4

2

R1571

R1570

+-

1

7

DIGITAL BOARD

MAIN BOARD AU SW BOARD

B+ 3

2

5

Description: This will exercise the Front Left, Front Right, Center, Left Surround and Right Surround channelsSo, data can be viewed on IC1301/ pin 24 (SOA Front Left/Right), pin 23 (SOB Center/Subwoofer), and pin 22(SOC Rear Left/Right). Reference Waveforms 5-3, 5-4 and 5-5 for example waveforms on IC1301/pin24, pin 23and pin 24. Note that the Subwoofer (LFE) is not being exercised. The Subwoofer can be tested using theYEDS-18 disc (100Hz track). The signal path can now be traced from IC1301, through IC1401, up to IC1503. Allines should show data activity. The Dolby DVD Demo and Test Disc have several other useful tracks for tespurposes. The description of each track is beyond the scope of this book, but would be very beneficial to

explore.

Circuit Description


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The signal from the analog switching ICs (IC301and IC303) passes through Buffer IC304 (located on the Mainboard), and then splits off in two directions after CNP11. One path is to IC1502 (Output Select IC), which is usedwhen the receiver is set to 2CH mode. Note: The digital board is totally bypassed when 2CH mode is selectedThe other connection is to the Digital board through CNP7 pin 1. The signal at this point can be viewed on eitheside of C1522 (6Vpp). The signal then goes through R1522 (10kohm), which causes significant signal loss andthe signal is too low to probe at IC1504/pin 6. The signal is amplified by IC1504 and the signal levels at theoutput are 1.4Vpp (pin 7) and 1.4Vpp (pin 1). The signals at pins 7 and 1 are identical, but 180 degrees out o

phase. The signal is then applied to the IC1503 (ref. Appendix for CODEC functional description) to be A/Dconverted. The digital output signal at pin 9 (IC1503) is difficult to view on an analog oscilloscope. Waveforms5-1 and 5-2 illustrate what can be viewed on an analog oscilloscope. Note:When attempting to view Waveforms5-1 and 5-2, use the HOLDOFF control on the oscilloscope to lock the digital packets on the display as shownThe display will only lock on the packets when an audio signal is applied; otherwise, the display will be unsteadyas shown below.


5V/div

10us/div

Trigger trailing edge

Adjust Holdoff

WAVEFORM 5-1DISPLAY LOCKED ON PACKETS

WAVEFORM 5-2DISPLAY UNLOCKED ON PACKETS

NOTE: There is no output signal at IC1503/pin 9 when in either 2CH or Analog mode (MODE button selection)The audio outputs of IC304 are also connected directly to IC1502 (Output Select IC). IC1502 selects inputs onpin 19 and pin 10 and sends it to the outputs as a 2-Channel format.

All the waveforms from IC1301/pins 22 (SOA), 23 (SOB) and 24 (SOC) to IC1503/pins 6 (SDI 1), 7 (SDI 2) and8 (SDI 3) are identical throughout the path (IC1301, IC1403, IC1401 and IC1503). Once again, in the digitadomain these waveforms are difficult to lock on the display of an analog oscilloscope. Waveforms 5-3, 5-4 and5-5 show what should be displayed when probing the three signal paths (SOA, SOB and SOC) in normal operationUse the HOLDOFF control to lock the data packets on the display. If there is not an analog input, the packets wilnot lock (unlocked waveform illustrated by Waveform 5-2). The main concerns while viewing these waveformsare: 1) there is no loss of data input (IC1301/pin 85) causing unlocked display condition; and 2) there is datapresent on all lines (no open traces).


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NOTE: There is no data present on the SOB and SOC lines in the following sound fields: Mono, Stereo and alHall modes. There is data only on SOA in these modes. Channel designation for SOA, SOB and SOC are asfollows:

SOA Front left/right

SOB Center/Subwoofer

SOC Rear left/\right

WAVEFORM 5-3IC1301 (SOA) Pin 24

WAVEFORM 5-4IC1301 (SOB) Pin 23

WAVEFORM 5-5IC1301 (SOC) Pin 22

IC1503 takes the three inputs at pins 6 (SDI 1), 7 (SDI 2) and 8 (SDI 3), performs the D/A conversion anddecodes the signal into the 5.1 Channel signals (Left, Right, Center, Subwoofer, Left Surround and Right Surround)

At this point, all the signals are analog and easy to trace through IC1507, IC1506 and IC1505, and then onto thepower amplifier stages.


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6. Digital Signal B lock

Digital Signal Block

WAVEFORM 6-1

S/P DIF

IC1201SYSTEM CONTROL

IC1101DIGITAL

AUDIOI/F

RECEIVER

IC001OPTICAL

RECEIVER

IC1007

WAVE

SHAPER

6

5 3

2

IC1002OPTICAL

RECEIVER

IC1003OPTICAL

RECEIVER

5

4

6

3

7

IC1005DIGITAL

INPUTSELECT

3 IC1301DOLBY

DIGITAL

AUDIODECODER

16 84

C11090.01uF

R11091M

SAME AS ANALOGBLOCK CIRCUIT

REF. ANALOGBLOCK DIAGRAM

6

D SIG

D/LD

SAT

T/MD

COAX

DVD/LD

OUT

IN

IN

IN

IN

SDI A

DATA IN

DATA

C1010

2pF

R1003100

R1011100

C102047pF

R1002

100

R10091k

C1007

22uF

R100875

R1001

100

D1101

R101356k

R1110

22k

B+

J1001

COAX

R1108100

R110210k

FIGURE 6-1 - DIGITAL SIGNAL BLOCK 3A124 1368 10/1/01

22

24

23

REAR L/R

CENTER SUB

FRONT L/R

Test Disk; YEDS-18

Track 2 (1KHz)

Circuit Description

The Optical inputs are fed into IC1001, IC1002 and IC1003 optical receivers. Here the Pulsing Light signal isconverted to an electrical/digital signal and applied to IC1005/pins 5, 4 and 3 respectively. The signal at this poinis in the S/P DIF format and is shown below in Waveform 6-1.

Oscilloscope Settings;

2V/div

2us

Trigger rising edge

Adjust Hold-off to lock display


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6. Digital Signal Block

WAVEFORM 6-2Sound Data Stream

The desired input signal is selected by IC1005/ pin 7(Digital Input Select). The input signal is then applied toIC1101/pin 3(Digital Audio I/F Receiver) .The digital signal format is still S/P DIF. The Digital Audio I/F Receivetakes the S/P DIF format, strips off all of the overhead control data and sends the sound data (e.g. Dolby DigitalDTS and 2CH) to pin 16. The Sound Data stream is shown in the Waveform 6-2.

Oscilloscope Settings;

2V/div

2usTrigger rising edge

Adjust Hold-off to lock display

The sound data stream then goes to IC1301/pin 84 (Dolby Digital Audio Decoder). The decoded extracts thethree mixed channel signals (Front L/R, Center/LFE and Rear L/R). The outputs from IC1301 are Front L/RIC1301/pin-24, Center/LFE IC1301/pin-23 and Rear L/R IC1301/pin-22. NOTE: The digital signal flow afteIC1301 is identical to the analog signal flow description. Reference the Analog Signal block diagram circuidescription and signal flow.


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7. Mute Signal Bloc

Mute Signal Block

IC1201

SYSTEM CONTROL

114 85 31

ERROR

SURROUND

MUTE

0V

NORMAL

SOFT

MUTE

R1241 R1247

10K 10K R121810K

MUTE

Q1507

QV S.W. BOARD

C1214

2200pf

Q1204

0V

NORMAL

DIGITAL

AUDIOI/F

RECEIVER

IC1101

34ERRORMUTE

R1110

0V

NORMAL

1K

AUDIO

CODEC

IC1503

3

S MUTE

FIGURE 7-1 - MUTE SIGNAL BLOCK 4A124 1 /21/ 02

Q1203

NOT USED ON STR-DE845

Circuit Description

NOTE: Reference figure 7-1 for the following circuit description.

The receiver is muted by one of three ways: 1) Surround Mute (front panel button); 2) Error Mute (an error in the

digital data input to IC1101) or 3) Soft-Mute (through software in IC1201 system control). All mute lines are at a

low state (0V) in normal operation (active high and are activated during the following actions:

1) Surround Mute: Output from IC1201 pin 85.

a) Depression of front panel mute button

b) While switching between inputs

c) While switching between sound fields

d) During power on

2) Error Mute: Output from IC1101 pin 34 and then applied to IC1201 pin 114.

a) If an error is detected in the data to IC1101 (input must be S/P DIF format)

b) If there is no connection to the optical or coaxial inputs (the device must also be powered on)

c) If the analog input is selected

d) During power ON

3) Soft Mute: Output from IC1201 pin 31. Not functional on this Model (Continuous LOW state).

The active high from the Surround mute and Error mute lines is applied to the base circuits of Q1204 and Q1203respectively. The active high turns the transistors ON, which then applies a low (ground) to the base of Q1507

on the AU SW board and hard mutes the audio outputs.


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8. Troubleshooting Block

Troubleshooting Block

Aside from confirming the normal operating signals and voltage already discussed in this course, the digitaboard can be troubleshot by dividing the board into specific sections using various normal operating modes

Figure 8-1 and the text below will describe how this can be accomplished.

1/21/02FIGURE 8-1 - TROUBLESHOOTING BLOCK 6A124

IC1401

DSP5.1 CH.AUDIO

INPUTSIGNALS

IC1301DIGITAL

AUDIODECODER

84

IC1403

BUFFER

IC1005DIGITAL

INPUTSELECT

IC1101DIGITAL

I/FRECEIVER

DIGITALINPUTS

IC1402SRAM

85 DATA DATA

DATA

ADDRESSIC1503CODEC

INPUTCIRCUIT

AUDIOINTERFACE

OUTPUT

CIRCUIT

9

DATADIGITAL INPUT

PATH ONLY

IC1504IC1554

4R AMPS

2 CH.AUDIO

INPUTSIGNALS

IC1502OUTPUT

SELECT

5.1 CH.AUDIO

FROM J307

5.1 CH.

AUDIO

SIGNALSTO AMPS

ANALOG INPUT

PATH ONLY

ANALOG INPUTSFROM IC304

MAIN BOARD

Troubleshooting Procedure

As can be seen from Figure 8-1, the analog and digital inputs follow two separate paths up to IC1301, and thenthe signal path is the same for both analog and digital all the way through to the speakers. This configuration can

be used to divide the circuit into sections and to determine in which IC a problem is occurring. The digital boardcan be divided into five sections using various inputs and receiver self tests. The following steps are not in any

particular order and can be performed in any order to better conform to the specific problem at hand:

Procedures:

1) The 5.1 Channel Input(J307) can be used to completely bypass the digital board circuitry. This input isapplied directly to IC1502. The circuits being tested are IC1502 and all audio and power amplifiers tha

follow. A DVD player with a 5.1 Channel output would be used for this test.

2) The 2 Channel (2CH) Mode (**with an analog Input signal**)can be selected to test IC304 (not shown

on Main Board), IC1502 and all audio and power amplifiers that follow. Once again, all digital boardcircuitry is bypassed.

3) Set the receiver for AFD or any Sound Field (e.g. Normal Surround), and select an Analog Input to se

up and test the following signal path:

Analog input IC304 IC1504 IC1554Partial IC1503 IC1301 IC1403 IC1404Partial IC1503IC1502Audio Amps

****ICs bypassed are IC1005 and IC1101


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8. Troubleshooting Block

4) Set the receiver for AFD or any Sound Field (e.g. Normal Surround), and select a Digital Input to seup and test the following signal path:

Digital inputIC1005IC1101IC1301IC1403IC1401Partial IC1503IC1502AudioAmps

****ICs bypassed are IC304, IC1504, IC1554 and Partial IC1503 (Input Circuit)

5) The DSP/SRAM Self Testcan be performed to check the operation of the DSP (IC1401), SRAM (IC1402)

and their interface. The DSP also outputs a 1KHz test tone (digital data on IC1404/pins 2, 3 and 4). Toenter the Self-Test mode from the POWER-OFF state, place the receiver in DSP test mode by pressingand holding the MODE and DIMMER buttons simultaneously while powering the receiver ON. The DSPoutputs data to the SRAM and then reads it back. If the data does not match, an error will be displayed(internal operation of DSP and SRAM, and the data and address buses are checked). The 1khz test tonecan be used to further section off the digital board. The following signal path is tested:

DSP IC1401IC1503IC1502Audio Amps

****ICs bypassed are IC304, IC1504, IC1554, Partial IC1503 (Input Circuit), IC1301, IC1005, IC1101 andIC1403

Example of a trouble analysis using above procedures:

Customer complaint: Experiences distortion when connected to the DVD/LD optical input jack. Technicianconfirms complaint.

Procedure:

1) Performing the DSP/SRAM Self Test will quickly divide the digital signal path in half. If the self tespasses and there is no distortion in the 1KHz test tone, then the distortion is being caused by one offour ICs: IC1403, IC1301, IC1101 or IC1005.

2) Now perform procedure number 3 above - the Analog Input test. If the distortion is still not presentthen the problem is with IC1005 or IC1101. If the distortion occurs on all digital inputs including thecoaxial input, then the Optical receiver ICs can be eliminated (not shown on this diagram). The dataon the output of IC1005 can be checked for any distortions (ref. S/P DIF signal waveform figure). Ino distortion is present, the defective component is IC1101.

With a little thought and creativity, most problems on the digital board can be troubleshot to component leveusing these five procedures in various orders.


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9. DAV-C700 Switch ing Type Power Supply

DAV-C700 Switching Type Power Supply

This switching power supply description and troubleshooting currently applies to these three Sony models:

DAV-S500 (HCD-S500)

DAV-C700 (HCD-C700)

DAV-C900 (HCD-C900)

Switching Power Supply Advantages

Although switching power supplies have the disadvantage of containing more parts than a 60 Hz. power transformesupply, the following advantages listed in Chart 9-1 outweigh this disadvantage:

Chart 9-1 - Advantages of Switching Power Supplies

1. Low cost (much cheaper power transformer) 4. Lower heat generated (higher efficiency)

2. Lightweight (small transformer) 5. Small or same size

3. Excellent voltage output stability (regulation) 6. Can operate over wide input voltages.

Concerns and Procedures

With switching power supplies, new safety concerns, circuit details and repair procedures are divided into thefollowing sections:

Safety for both you and the circuit

Power supply operation

Power supply regulation

How to troubleshoot the power supply

Testing the power supply unloaded

Troubleshooting shortcuts

I - Safety for You and the Circuit

When repairing products with pulse power supplies,you MUST use an isolation transformer for techniciantest equipment and product safety. The external isolation transformer just prevents immediate damage to

your instruments and the product.

In the power supply circuitry there is a HOT groundthat is connected to one side of the AC line and a COLDground that is often the same as chassis or speaker ground, isolated from the AC line. Use the correc

ground when measuring voltages.

Lethal voltages are still present during troubleshooting so caution must be observed.

II Power Supply Operation

This section is divided into the following topics:

Power Supply Control what turns it ON/OFF

Switching Power Supply Block Overall operation

Power Supply Operation Standby Mode

Power Supply Operation Power ON Mode


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9. DAV-C700 Switching Type Power Supply

Power Supply Control

See Figure 9-1 for the control of the power supply stage. In this A/V product there is:

A front panel latching master power ON/OFF switch (S901) that applies AC power to the product;

5.6V applied to the CPU when the power supply is in the Standby mode; and

Voltages output the power supply (not shown) when the CPU is instructed to turn ON the power supply.

Switching

Power Supply

Figure 9-1 - Switching

Power Supply Control

CPU

IC901

Serial to

Parallel

IC902

SWQ002AC

Master Pwr

S901 Play

Eject

Remote

Control

Data

5.6V

P Cont 2

M12V

to

Driver

IC401

13V

P Cont 1

There are two power ON commands from CPU IC901 (DVD board) to the switching power supply. P Cont 1takes the switching power supply out of the Standby mode and into the ON mode. The power supply will outpu

four voltages (not shown), powering up the unit. Both P Cont 1 and 2 go HIGH when the DVD/CD mode isrequested. The power supply produces an additional voltage of 3.3V in the DVD/CD mode (not shown).

Switching Power Supply Block

Refer to Figure 9-2 for the following power supply block description. Each switching power supply has a

fundamental oscillator/voltage output section and a control section. The oscillator section always uses a high

frequency oscillator (IC901) to feed a small power transformer (T901). The power transformer has multiplesecondary windings to deliver the various voltages the product needs to function.

The control section varies in any switching power supply to meet the product needs. In this product, the switching

power supply must output 5.6Vdc when the unit is plugged in (standby mode) and the remainder of voltageswhen the unit is powered ON. This means the switching power supply is partially operational when AC power is

applied.

SW. Q915

STANDBY

D912

SW.

Q907, 9

IC905

ERROR REG.

IC902

SWITCHING

REGULATORIC901SW.

Q901,

Q902

REG.

Q903,

D903

POWER

TRANSFORMER

T901

D902IC906

IC903

62Vdc

TH901

9.1

163V

13V

Vcc20V STBY = 11V

ON = 20VSTBY = 0VON = 5V

5.6V

P CONT 1

13V

27V

P CONT 2

3.3V

6.5V

P CONT 1

PRIM. SEC.S901

F901

5A

FIGURE 9-2 - DAV - C700 POWER SUPPLY BLOCK 11/27/019.1A124 1416


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ch1: pkpk= 246 V

ch1: freq= 11.6kHz

CH1!50.0 V= MTB1.00ms- 0.78dv ch1+

1

T

This switching power supply actually has four modes of operation: OFF, Standby, Power ON and power ON in

DVD. In the OFF mode, S901 is open. In the standby mode, S901 closes, the oscillator (IC901) outputs in burstsand the error regulator (IC902) is disabled (by D912) to prevent the oscillator from shutting down. In standby, the

power supply only outputs 5.6 volts (and 19Vdc from the 27V line). In the power ON mode when P Cont 1 goesHIGH, the oscillator switches to a continuous sine wave output and the error regulator is enabled to maintain a

stable 27Vdc output. In the power ON in DVD mode, P Cont 2 also goes HIGH, turning ON regulator IC906

IC906 outputs 3.3 Vdc to the DVD board.

Power Supply Operation Standby Mode

When front panel S901 is closed, AC is input to the switching power supply and the supply enters the Standby

Mode to output 5.6Vdc. At one of the AC inputs of bridge rectifier D902, 62Vdc is available with respect to ho

ground. This voltage is regulated by Q903 down to 20Vdc and applied to switches Q901-Q902. In the standbymode, only 11Vdc is passed by the switches into Switching Regulator IC901 at Vcc. With 11Vdc input IC901, the

oscillator outputs bursts of 200kHz. See Waveform 9-1.

Waveform 9-1 - Standby Mode IC901 Output

Name Location Voltage/divChannel 1 Drain Output C916 / IC901/pin 3 248Vp-p

Time base 1msec/div

The burst output of IC901 is applied to power transformer T901. T901 outputs two (standby) voltages, listedin Chart 9-2:

Chart 9-2 - T901 Output Voltages (after rectification)

Standby Mode Power ON

9Vdc 13Vdc

19Vdc 27Vdc

To keep T901s output voltages present but reduced in the standby mode, the error regulator (IC902) must bedisabled. That is the function of D912. To prevent IC901s oscillator from shutting off, D912 is enabled to bringup the error input voltage at IC901/pin 1 to within the operating range of 0.8V 4Vdc. See Figure 9-3. D912 is

enabled using inverters Q905 and Q908. In the standby mode, P Cont 1 = 0Vdc. This voltage is inverted byQ905 and Q908, placing 0Vdc (gnd) at D912s Anode, enabling it. D912 clamps the voltage into PC901 (disabling

IC902) and PC902 outputs 9.5V at pin 3. This 9.5V output voltage is reduced by R912 to produce 1.1Vdc a

IC901/pin 1 to keep the oscillator alive.


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Chart 9-3 - Standby Mode IC901 Control Voltages

Switching Regulator input Voltage Purpose

IC901/pin 4 (Vcc) 11 Vdc Vcc input for burst oscillator output

IC901/pin 1 (Error correction) 1.1 Vdc Fixed error correction voltage to prevent oscillator shutdown

If a circuit failure disabled D912, error regulator IC902 would be operational, outputting a correction voltage of

about 0V to Switching regulator IC901/pin 1 in this oscillator burst (standby) mode. This 0Vdc is output becauseIC901 is producing less power (outputting only bursts), but error regulator IC902 outputs 0V attempting to raise

the output to normal. Unfortunately, 0V is below the normal operating range of the oscillator in IC901 so IC901would attempt oscillation a few times and finally shut off. If shutoff occurs, removing Vcc to IC901 will reset it.

Consequently, both of these two control voltages must be input for oscillator IC901 to function in the Standby

Mode. See Chart 9-3 below:

IC905REG

BA05T901

POWER

TRANS.

PC901

ISOLATORTLP421

IC907INV.

TE85R

3

4 1

2

4 5

2

4

IC901

SW REG

STRF642651

3

R907

D903

18V

Q903

18V

SOURCE

D904

NP

Q902

P

Q901

S901F901

5A

D902

TH901

163V

+C902

5.6V+18V

PC902

TLP421

ISOL.

R908

33k1W

62Vdc

C91624V

SOURCE

R905

11V=STBY 20V=ON

FIGURE 9-3 - DAV- C700 POWER SUPPLY CIRCUIT

9.1

6.8V=ON

18V=STBY

5.6V Vcc

3

4

24V

2

2

IC902

ERRORSE-B2

1

3

4

1

R904

R919

R920

P CONT 1

(DVD BD.CN008)

5.6V

TO CPU

IC901

(DVD BD.)

STBY=19VON=28V

STBY=0VON=4.7V

HOT

COLD

R912HEAT

SINK

13V

27V LINE

R917

R916

D912(15V)

Q915

Q905

Q908

CHASSIS

CN904

1.1V 9.5V 0V 17V

2.2V 7.5V 13V 27V

STBY

ON

IC901/1 PC901/3 D912/A IC902/2

CN905

2

10

11/27/019.2aA124 1415

Power Supply Operation Power ON P.Cont 1 comes from the CPU and is used to toggle the power supplybetween the Standby Mode (LOW) and the Power ON Mode (HIGH). In the Power ON mode, the HIGH has two

purposes. The first is to apply full voltage to switching regulator IC901/pin 4 (20Vdc). See Figure 9-3. Thischanges the oscillator output of IC901 from a burst signal to a continuous oscillator output.


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, I I

ch1: pkpk= 301 V

ch1: freq= 213kHz

CH1!50.0 V= MTB2.00us- 0.54dv ch1+

1

T

Waveform 9-2 - Normal IC901 Output at Power ON 213kHz (205kHz in DVD)

Name Location Voltage/div

Channel 1 Drain Output C916 / IC901/pin 3 300Vp-pTime base 2usec/div

To do this, P.Cont 1 turns ON Q915, which forces Inverter IC907 to output a HIGH at pin 4 for PC902. The

transistor in isolator PC902 turns OFF, allowing switches Q901 and Q902 to fully conduct (via R905). As a resultthe entire regulated 20Vdc from regulator Q903 (emitter) is applied through Q902 (e-c) into switching regulator

IC901/pin 4. The higher Vcc voltage causes IC901 to change from a burst output to a continuous sine waveoutput in the Power ON Mode. The continuous sine wave output is shown in Waveform 9-2.

The HIGH at P.Cont 1 has a second purpose. It is also used to enable error regulator IC902. In the Power ON

mode when P.Cont 1 is 5Vdc, D912 is switched out of the circuit. Q908 turns ON and Q905 turns OFF so D912sanode is floating and effectively out of the circuit. When D912 is no longer clamping IC902/pin 2s outpu

voltage, IC902 can regulate the 27Vdc output from T901.

Figure 9-3 shows the regulating circuit. The regulation components consist of IC902 and PC901. Both act as

inverters. IC902 is the error regulator, monitoring the 27 volt line at pin 1 (Pwr On = 6.3Vdc). PC901 is anoptical-isolator, isolating the cold ground from the hot ground signal. PC901 also acts to invert the signal from

IC902. If the 27V-output line increases, the resultant correction voltage input the switching regulator IC901/pin

1 also goes high to compensate.

III - Regulation

The power supply output regulation was not fully explained in the switching power supply operation. The mystery

of how the DC error correction voltage input IC901/pin 1 controls the power supply output voltage is not necessaryfor repairs, but is important to completely understand the switching power supply regulation concept.

Concept

In this switching power supply there is a frequency controlled oscillator (IC901) and a resonate circuit load. The

resonate circuit is formed by power transformer T901 (the inductor = L), and C916 (the capacitor = C). Theseparts are located at the top of Figure 9-3.


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Normal OperatingPoint (200kHz)

T901

Output

FrequencyFigure 9-4 T901Output Curve

T901

C912820

200V C916

2

3

4

5 1

1

2

3

4

9

10

11

CN905CN9041

11

COLDGROUND

TH901

D902

R908HOT

GROUND

R902

R903

SW REG.IC901

D911HEAT SINK=COLD GROUND

OUTPUT INPUT

13V

6.5V

3.3V

5.6V

P.CONT 1

P.CONT 2(DVD ONLY)

RESET

5.6V - STBY/ON

D909

PC901

(REG)

PC902

DAV C700

POWER BOARD

FIGURE 9-5 - DAV C700 POWER BOARD

27V

OUTPUT

10/19/019.5A124 1383

D912

By setting the input oscillator frequency (the Normal Operating Point in Figure 9-4) to above the resonancepoint, T901s output voltage can be adjusted by changing the input frequency. The input frequency can be

changed by adjusting the DC error voltage into IC901s oscillator (pin 1). When the normal operating point is

above resonance as shown in Figure 9-4, T901s output voltage is inversely proportional to its input frequency.

IV - How to Troubleshoot the Power Supply

There are three complicated failures that require a troubleshooting plan:

Power Supply is Dead - No voltages

Power Supply will not Power ON - Standby voltage is OK Output Voltages are Low One or more voltages are low or high

Refer to Figure 9-5 for the location of grounds and accessible components used for troubleshooting.

T901s output voltages are dependent upon the match between its resonate frequency and the input frequency

from the oscillator (IC901). When IC901s oscillator frequency is the same as the T901-C916 resonate frequencythere is maximum power transferred from T901s primary to secondary, producing maximum output voltage

(peak of Figure 9-4s bell curve).


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Power Supply is Dead

Normally when you press the front panel ON switch, the CPU (on the DVD board) is powered with 5.6Vdc. The

unit can then power ON when you press either the front panel Play or one of the five Eject buttons. The displaywill then illuminate, showing the units model number and then the input mode - DVD.

In the following steps, you will verify the voltages necessary to sustain the oscillator operation. You must usean

isolation transformerand be cautiouswhen probing the components to avoid shorting parts. First, locate thehot and cold grounds using Figure 9-5.

1. Plug the unit into AC and press the front panel Power button IN (should latch in).

2. Measure the PS Output voltage at CN904/pins 1 or 2 (normally 19Vdc in this Standby Mode). Refer to Figure

9-5 to locate the cold ground for this voltage measurement.

NO voltage - proceed to step 3 (next). The power supply is dead.

19V is present - Go to step 8. The power supply is running in standby mode but may not power ON.

3. Verify 163Vdc from the bridge rectifier at either end of 9.1-ohm TH901. Use the HOT ground at R902 (Fig 95).

4. This 163Vdc should pass through T901s primary winding and appear at IC901/pin 3, which is inaccessible

from the top. Check for this voltage at the lead of C916 nearest R903. Use HOT ground at R902 (Fig 9-5)

5. Verify about 60Vdc and 24Vdc at the two leads of R908. This is the lower voltage from the bridge rectifieD902, reduced by R908. Use the HOT ground at R902 (Fig 9-5).

6. This voltage should be regulated by Q901-Q903 down to 11Vdc at IC901/pin 4 in this Standby Mode (20Vdc

when the unit is ON). Use the HOT ground at R902 (Fig 9-5).

7. If these voltages in steps 1-6 are present, IC901 should be oscillating, producing the two Standby Modevoltages listed in Chart 9-5. Use the cold ground at D909s heat sink (Fig. 9-5). If the two standby voltages

are present, the standby section of the supply is OK, the problem is that the power supply will not turn ON (go

to step 9). If the supply voltages are missing, the power supply is in protection (next step 8) or the oscillator(IC901) is defective.

Chart 9-4 - Power Supply Output Voltages Use Cold Ground

Location Standby Mode Power ON ModeCN904/pin 1, 2 19Vdc 27Vdc

CN905/pin 1 0.22Vdc 13.6Vdc


CN905/pin 3 0V 3.3Vdc


8. If there are still no standby output voltages, the power supply may have started and gone into protectionWhen the front panel power button is pressed and the oscillator at IC901/pin 3 (actually scope probed at

C916) appears (as bursts), then stops, IC901 is in protection. An incorrect voltage input to IC901/pin 1 could

cause this. An applied voltage above or below 0.8-4Vdc will stop the oscillator. This operating voltage comesfrom the regulator parts PC901, D912 and IC902 all of which must be checked.

Power Supply will not Power ON

9. If both standby voltages are present (see Chart 9-4), the power supply works in standby but will not poweON, causing the dead power supply symptom. Check for a normal 5.6Vdc (reset) from the power supply to

the CPU at CN905/pin 9. Zero volts inhibit the CPU (held at reset) so the CPU cannot turn the power supply

ON. This reset line (not shown) comes from the power supply board.

10. P Cont 1 at CN905/pin 10 should change from 0Vdc (standby) to 4.7Vdc (ON) when the front panel PLAY oany Eject button is pressed. Measure P Cont 1 at CN905/pin 10. If this voltage:


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Remains at 0V - CPU IC901 on the DVD board is not outputting this power ON command.

Goes to 4.7Vdc - the problem is on this power supply board. Go to step 11.

11. Use Figure 9-5 to locate D912/Anode and measure its voltage. A normal 13Vdc when P Cont 1 is HIGH

(powered ON) means the regulator parts are defective. Check or replace IC902, D912 and PC901. If youmeasured 0Vdc at D912/Anode, Q905 or Q908 is defective.

Output Voltages are Low in the Power ON Mode

One voltage missing- If one output voltage were missing, you would troubleshoot that output line for a deadshort in the load or an open in the source voltage line.

One or more power supply voltages missing- When one or more power supply output voltages are low, theproblem is either an excessive load or the power supply cannot deliver the normal current. Use Chart 9-5 to

determine if the load is within the normal range.

Chart 9-5 Power Supply Load Current

Output Voltage Location Tuner Mode Video Mode DVD Mode

27V CN904/pins 1 and 2 367 ma 367 ma 367 ma

13Vdc CN905/pin 1 200 ma 227 ma 581-1,200 ma

6.4Vdc CN905/pin 2 823 ma 843 ma 823 ma3.3Vdc CN905/pin 3 2.6 ma 2.5 ma 446 ma

5.6Vdc CN905/pin 4 70 ma 70 ma 82 ma

The wires from CN905 may be removed for current tests by lifting the plugs wire holder.

All T901 voltages are LOWor HIGH- If ALLthe T901 power transformer output voltages are proportionallylow or high, the regulating stage or the basic power supply cannot deliver the voltage or normal current. Use

Chart 9-6 (steps 1-3 along the top) to help determine which of these stages is not operating properly.

Chart 9-6 - Troubleshooting for Incorrect Output Voltages

1.Power ON and measureCN904/pin 1 voltage

2.Measure PC901/pin 3 (use HOTgnd). Typical voltage is 7.5Vdc

3.Suspect

This voltage is Higher Basic Power supply IC901, T901, C91627V Output Voltage=Higher than normal This voltage is Lower Error regulator parts about IC902, PC901

This voltage is Higher Error regulator parts about IC902, PC90127V Output Voltage=Lower than normal This voltage is Lower Basic Power supply IC901, T901, C916

PC901/pin 3 voltage is normal- If the voltage at PC901/pin 3 is a normal 7.5Vdc (Chart 9-6, step 2),

either: 1) test the power supply unloaded in the next section; or 2) follow the troubleshooting steps inPower Supply is Dead because the supply may be partially in the standby mode causing the low output

voltages.

V - Testing the Power Supply Unloaded

You can run this power supply unloaded to determine if the power supply could generate a voltage, but the outpu

voltages will be a little higher than normal.

1. Unplug both output connectors CN904 and CN905.

2. Connect CN905 pin 4 to pin 10. Caution: When counting pins, the second pin has no number so the pincomplement of connector CN905 is: 1, X, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. When in doubt, count from pin 11 to the

pins you want. Connecting pins 4 to 10 places the standby voltage into the power ON line.


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3. Plug the unit into AC and press the front panel Power ON switch so it latches in. The power supply should

start and produce the following voltage. See Chart 9-7 below:

Chart 9-7 - No Load Power Supply Output Voltages Use Cold Ground

Location No Load Voltage Normal Power ON Voltage

CN904/pin 1, 2 27-29Vdc 27Vdc



CN905/pin 3 0V * 3.3Vdc


* 3V will output if a HIGH is also placed at CN905/pins 10 & 11.

VI - Troubleshooting Shortcuts

Because the circuit board is dense, access to some parts is difficult or impossible from the top of the board.Temporally changing circuit conditions to see if some circuit groups work in this power supply is a good way to

speedily arrive at the non-working part. These shortcuts do not replace a complete troubleshooting plan.

Chart 9-8 - Shortcut ProceduresPurpose Conditions Procedure Normal Result Parts Tested

See if CPU pwr ONcommand arrives atPC902

Standby Mode (frontpanel button in)

Press the Playor an Ejectbutton to powerON.

Voltage atPC902/pin 2should changefrom 4.7V to5.6V

Stby voltage,IC907, Q915, PwrON Path fromCPU (DVD bd.).

See if CPU pwr ONcommand finallyarrives at IC901/pin4.

Standby Mode Releasefront panel Pwr to turnOFF unit, then pressbutton in again.

ShortPC902/pins 1and 2 together.

Voltage atIC901/pin 4should changefrom 11V to 20V.

Q901-Q903,D903, PC902

See if CPU pwr ONcommand alsoenables theregulating circuit(cancels the StbyMode).

Standby Mode Releasefront panel Pwr to turnOFF unit, then pressbutton in again.

Press the Playor an Ejectbutton to powerON.

Voltage atD912/Cathode(band) shouldchange from14.8V to 28V

D917, Q905,Q908.

PS. Shorting pins of PC901 (regulating circuit) will cause IC901s oscillator to stop until power is removed (no

damage will result). The power supplys 27V output line will momentarily rise from 19V to 38Vdc when pins 1-

2 are shorted, or decay toward 0 when pins 3-4 are shorted.

Caution: Never cause the power supply output to go to a maximum of 38Vdc while connected to the load.


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10. Hi-Fi Output Troubleshooting Overview

Hi-Fi Output Troubleshooting Overview

10/26/0110.1A124

V I

SWITCHED AC OUTLET(s)(Outlet shape and position variesaccording to destination)

FIGURE 10-1

Troubleshooting Audio Power Amplifiers is frequently a matter of simply changing a pair of output transistorsOther times the protection light just will not go off. In the worst-case scenario, the newly replaced transistors aredestroyed as power is applied. In this document we will examine troubleshooting methods for the more difficul

problems. We will break down our problems into two types:

Excessive Current Draw Constant Protection Light Indication

We start with the following assumption: you have changed two or more output transistors. Because of thepossibility that the new transistors will be damaged, it is wise to take a cautious approach when applying powerto the unit. A Variac will be used to slowly increase the AC power to the unit while watching for excessivecurrent draw. Before power can be applied in this way, the power relay must be bypassed. Of course, you canlocate the power relay and simply add jumpers to the relay contacts. There is a quicker way to bypass the powerelay, but it requires a very dangerous tool. This tool (shown in Figure 10-1) is like an extension cord only it hastwo male ends. If this cord is ever plugged in to the AC outlet first, the other end will be live and exposed. Keepthis tool safely away from anyone not familiar with electricity.

By FIRST plugging this cord into the SWITCHED outlet on the rear panel of the receiver, then SECONDLYplugging it into the AC outlet of a Variac, you will bypass the power relay. Now, slowly increase the AC voltagewhile watching the current meter on the Variac for a sharp increase in current. If the current raises rapidly, STOPlower the voltage back to 0 volts and turn to the Excessive Current Draw section of this document. If the uni

does not draw excessive current by the time the AC voltage reaches 100 volts, turn the Variac voltage back to 0volts. Then remove the bypass cord and connect the unit to an AC outlet in the normal manner and press thepower button.

The Power Amplifier can be broken into three sections (shown in Figure 10-2):

Output stage

Bias network

Driver Amplifier


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10, Hi-Fi Output Troubleshooting Overview

DRIVEAMP

BIASNETWORK

+

-

FB FBOUTPUT

TORELAY

OUTPUT(-)

(+)

AUDIO

IN

FIGURE 10-2 10/26/0110.2A124

Problems with the bias network usually cause excessive current draw. In rare cases, bias network problems maycause crossover distortion. Problems with the Driver amplifier cause small DC offset voltages to appear at theamplifiers output (speaker connection). Problems with the output stage cause either excessive current draw(both outputs shorted C/E) or large DC offset voltages at the amplifiers output (one output transistor shortedbetween C/E). As problems with the Output stages are the most common and easily found with an ohmmeterwe will focus on the other two areas.


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11. Troubleshooting Driver Amplifier & Bias Network Circuits

Troubleshooting Driver Amplifier & Bias Network Circuits

BIASNETWORK FB

OU

RE

OUTPUT(-)

(+)

FIGURE 11-1 - PROTECTION MODE 10/30/11.1A124

1 2 4 5 6 7 83 9

VCC

VSS

+VEOUT

-VEOUT

IC601STK350-230

HF

INPUT

(+)

(-)

-57.5

1.1

-154.4

C606

R605470

C

603

54.3

C604

R604 68

R603330

R60268

C60547

16V+

C602100 FB

-0.1

-0.1

+

C60110

50V

R6011

IN

2

3

4

6

7

8

9

1

TR3

TR2

TR1

R1

R2TR4

5

R9

R4 TR5

D1 R5D2

TR8

R8 R7

D4 D3R3

TR7

TR8

R5

INPUT

NF

-VEOUT

+VEOUT

V55

GNO

VCC

IC601 STK350-230

Protection light will not go off after replacing Output transistors

Most modern Power Amplifiers use an IC package for the Drive Amplifier (shown in Figure 11-1). If you havesmall DC offset voltages at the Driver amplifier output, the protection circuit will be triggered and the receiver wilenter the protection mode. In this case, change the Driver amplifier IC. If that does not solve the problem, check

the positive and negative power supplies to the Driver amplifier IC. Sometimes there are switching networks inthe B+ and B- paths to the Driver amplifier IC. These switching networks are used to limit the gain of the Driveamplifier.

NOTE: Small offset voltages on multiple channels are usually caused by bad ground connections (troubleshootfor open ground trace or traces).


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FIGURE 11-3 - TROUBLESHOOTING BIAS 10/26/0111.3A124

STR-GX47ES

BIASNETWORK

FB OUT

(-)

(+)

IN DRIVEAMP

FB

STR-D315

BIASNETWORK

FB OUT

(-)

(+)

IN DRIVEAMP

STR-DE615

BIASNETWORK

FB OUT

(-)

(+)

IN DRIVE

AMP

Obviously the Jumper Method is much slower (but a lot safer) than the Find the HOT transistor method. recommend practicing both methods as physical access limitations shift the advantage from one method to theother. NOTE: Service bulletin HPF0643 covers a Bias Circuit change for receiver models STRV555ESSTRV444ES, and STRV333ES.

Troubleshooting Bias Network Circuits


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Once you have located the bad channel, it is time to shotgun (due to very few components) all the active components(diodes or transistors) in the bias network. Shotgunning is preferred since intermittent bias components cancause expensive damage to the Power Amplifier. While changing the active components, carefully inspect alresistors and potentiometers. Now it is time to verify that the unit does not draw excessive current while followingthe power relay bypass procedure.


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12. Troubleshooting Audio Protection Circuits

Troubleshooting Audio Protection Circuits

FIGURE 12-1 - PROTECTION BLOCK 10/26/0112.1A124

CH1OVER

CURRENTPROTECT

+/- OFFSETPROTECTCH1

POWERAMP

CH2

CH3

CH4

CH5 CH2 OCP

PROTECT

OUT SYSCON MP

PROTECTIN

CH4 OCP

CH3 OCP

CH5 OCP

TOSPEAKER

PROTECTIONRELAY

The most common problem in audio receivers is protection light is ON and no sound. The usual cause is oneor more shorted Output transistors in one of the Power amplifiers. In many cases, you can find the source of theproblem with an ohmmeter by checking the E/C juncti

26441030 training manual

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