Sony STR-DE845 Training Manual Download Page 44 | Manualshive

Page: 44 / 61

background image

42

11. Troubleshooting Driver Amplifier & Bias Network Circuits

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 can
cause expensive damage to the Power Amplifier. While changing the active components, carefully inspect all
resistors and potentiometers. Now it is time to verify that the unit does not draw excessive current while following
the power relay bypass procedure.

«
...
42
43
44
45
46
...
»

Summary of Contents for STR-DE845

Page 1: ...i Product Hi Fi Technology and Troubleshooting Course A 124 Digital Board Hi Fi Output Model STR DE845 Troubleshooting Switching Power Supply Super Audio CD Model DAV 700 900 New Technology DAV S500 HCD S500 HCD C700 900 S ...

Page 2: ... 28 Regulation 32 How to Troubleshoot the Power Supply 33 Testing the Power Supply Unloaded 35 Troubleshooting Shortcuts 36 10 Hi Fi Output Troubleshooting Overview 37 11 Troubleshooting Driver Amplifier Bias Network Circuits 39 Protection light will not go off after replacing Output transistors 39 Excessive Current Draw 40 12 Troubleshooting Audio Protection Circuits 43 Offset Protection Circuit ...

Page 3: ...put The information in this book will also help the technician determine whether a customer s 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 digital board will also be covered showing the DSP circuit changes as compared to the STR DE845 only The overall operation of the digital board in ...

Page 4: ... detects the type of audio signal Software Format being input e g Dolby Digital Dolby Pro 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 the source sound exactly as it was re...

Page 5: ...eakers Depending upon where the actual rear speakers are positioned the virtual speakers positions 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 t...

Page 6: ... 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 sets of virtual rear surround speakers surrounding 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...

Page 7: ...FE FIGURE 2 10 1 2 3 1 2 3 R C L LFE 5 Virtual Enhanced B Uses 3D image processing to create one set of virtual rear speakers This is accomplished using only the front left and right speakers without using actual rear speakers ref Figure 2 11 ...

Page 8: ... pictures Entertainment scoring stage This sound field is ideal for viewing musicals or classic films where music is featured in the soundtrack 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 cases even have particular characteristics for ce...

Page 9: ...deo Games Game This sound field is designed to be used with video game software and a stereo input This mode will 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 actual audio applied to them by the receiver for the software while in a particular sound field mode Chart 2 1 ...

Page 10: ... the impedance of each speaker must not be less then 8 ohms and the impedance switch must be set for 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 and audio is applied to the speaker 2 There are not...

Page 11: ... R S V M ulti R ear L C R LFE LS RS W ith additional virtual speakers L C R S L C R S L C R S V Sem i M D im ension L C R All other speakers virtual L C R All other speakers virtual L C R All other speakers virtual Virtual Enhanced A B L C R LFE All other speakers virtual L C R All other speakers virtual L C R All other speakers virtual L C R All other speakers virtual L C R LFE All other speakers...

Page 12: ...The 5 1 Channel Input actual consists of six signals Front Left Front Right Rear Left Rear Right 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 c...

Page 13: ...NNA FIGURE 3 1 STR DE845 ANALOG DIDITAL INPUTS COAXIAL FM 75Ω DEVICES MD DAT TV SAT SOFTWARE FORMATS DOLBY DIGITAL AC 3 5 1 DTS 5 1 DOLBY PROLOGIC PCM 48kHz 41 1kHz 32kHz DVD LD DVD LD COAX SOFTWARE FORMATS DOLBY DIGITAL AC 3 5 1 DTS 5 1 DOLBY PROLOGIC PCM 96kHz 48kHz 41 1kHz 32kHz DEVICES DIGITAL INPUTS SUB WOOF IMPED SPEAKERS 10 15 01 13CA124 1380 Table 3 1 Digital Input Sampling Frequency Compa...

Page 14: ...rom the Tuner antenna section is also an input to the digital board It is processed the same as any of the other analog inputs in order to apply the desired sound field effects The input signals to the tuner are off the air FM and AM signals There is also an analog Video 3 Input on the front panel of the receiver that can accommodate another VCR Software Formats Illustrated Dolby Surround Prologic...

Page 15: ...OWN MIXED into any other format depending on the decoding applied This is similar 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 5 Dolby Digital EX 6 1 R C L LS RS LFE CS A center screen channel or speaker is necessary to ensure the precise localization of the ...

Page 16: ...d Chip Enable Lines All control signals are supplied by IC1201 System Control IC1201 Pins 108 and 107 control the digital input selection of IC1005 pins 2 and 14 These control lines are a simple two bit input Table 4 1 shows the two bit code for the corresponding input The resistors on the output of IC1201 R1282 and R1281 and on the input of IC1005 R1006 and R1007 are easy probe points to confirm ...

Page 17: ...ITAL AUDIO DECODER RST IC1404 SDI CLK CE R1289 R1286 R1288 1 2 3 5 R1265 R1270 R1275 82 83 12 282MHz X3501 12 282 MHz LR CLK BCLK 15 14 26 IC1401 AUDIO DSP HAD CE RST 97 70 74 41 17 IC1402 SRAM 6 25 16 26 5 4 39 IC1503AUDIOCODEC 43 11 41 17 42 30 35 28 32 29 LRCLK MCLK R1263 R1252 R1242 R1245 R1285 IC1202 RST 96 KHz 96 KHz RST CE HAO CE CLK CDTI CDTO RST CLK CLK RSTCLK RST CE SDO SDO CE PDO PDI RS...

Page 18: ...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 the digital inputs and that 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 pa...

Page 19: ...6Mhz 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 1 A5 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 mainly used for the processing of the Cinema and Hall sound fields where reverberation Delay is requi...

Page 20: ...rformed in the DSP internal RAM The third 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 the Waveforms 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 confi...

Page 21: ...bwoofer channel will be present when using the 1KHz signal Track number 4 100Hz signal on the YEDS 18 disk can be used to produce signals on the LFE channel 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 The signal path after IC1301 is broken into three separ...

Page 22: ...ALOG 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 channels So 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 23 an...

Page 23: ...gital packets on the display as shown The display will only lock on the packets when an audio signal is applied otherwise the display will be unsteady as shown below Oscilloscope Settings 5V div 10us div Trigger trailing edge Adjust Holdoff WAVEFORM 5 1 DISPLAY LOCKED ON PACKETS WAVEFORM 5 2 DISPLAY UNLOCKED ON PACKETS NOTE There is no output signal at IC1503 pin 9 when in either 2CH or Analog mod...

Page 24: ...ter Subwoofer SOC Rear left right WAVEFORM 5 3 IC1301 SOA Pin 24 WAVEFORM 5 4 IC1301 SOB Pin 23 WAVEFORM 5 5 IC1301 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 and decodes 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...

Page 25: ...pF R1003 100Ω R1011 100Ω C1020 47pF R1002 100Ω R1009 1k C1007 22uF R1008 75Ω R1001 100Ω D1101 R1013 56k R1110 22k B J1001 COAX R1108 100Ω R1102 10kΩ 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 is co...

Page 26: ...TS and 2CH to pin 16 The Sound Data stream is shown in the Waveform 6 2 Oscilloscope Settings 2V div 2us Trigger 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 the three mixed channel signals Front L R Center LFE and Rear L R The outputs from IC1301 are Front L R IC1301 pin 24 Center LFE IC1301 pin 23 an...

Page 27: ...ration 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 ...

Page 28: ...he 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 board can 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 s...

Page 29: ...s tested DSP IC1401 IC1503 IC1502 Audio Amps ICs bypassed are IC304 IC1504 IC1554 Partial IC1503 Input Circuit IC1301 IC1005 IC1101 and IC1403 Example of a trouble analysis using above procedures Customer complaint Experiences distortion when connected to the DVD LD optical input jack Technician confirms complaint Procedure 1 Performing the DSP SRAM Self Test will quickly divide the digital signal...

Page 30: ... divided into the following 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 technician test equipment and product safety The external ...

Page 31: ...n 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 multiple...

Page 32: ...egulated by Q903 down to 20Vdc and applied to switches Q901 Q902 In the standby mode 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 div Channel 1 Drain Output C916 IC901 pin 3 248Vp p Time base 1msec div The burst output of IC901 i...

Page 33: ...IC901 to function in the Standby Mode See Chart 9 3 below IC905 REG BA05 T901 POWER TRANS PC901 ISOLATOR TLP421 IC907 INV TE85R 3 4 1 2 4 5 2 4 IC901 SW REG STRF64265 1 3 R907 D903 18V Q903 18V SOURCE D904 N P Q902 P Q901 S901 F901 5A D902 TH901 163V C902 5 6V 18V PC902 TLP421 ISOL R908 33k 1W 62Vdc C916 24V SOURCE R905 11V STBY 20V ON FIGURE 9 3 DAV C700 POWER SUPPLY CIRCUIT 9 1Ω 6 8V ON 18V STBY...

Page 34: ... floating and effectively out of the circuit When D912 is no longer clamping IC902 pin 2 s output 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 an optical isolator isolating the cold groun...

Page 35: ...he DC error voltage into IC901 s oscillator pin 1 When the normal operating point is above resonance as shown in Figure 9 4 T901 s 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...

Page 36: ...en 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 Mode voltages listed in Chart 9 5 Use the cold ground at D909 s 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 volta...

Page 37: ...r output voltages are proportionally low 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 measure CN904 pin 1 voltage 2 Measure PC901 pin 3 use HOT gnd Typical voltage is 7 5...

Page 38: ... Tested See if CPU pwr ON command arrives at PC902 Standby Mode front panel button in Press the Play or an Eject button to power ON Voltage at PC902 pin 2 should change from 4 7V to 5 6V Stby voltage IC907 Q915 Pwr ON Path from CPU DVD bd See if CPU pwr ON command finally arrives at IC901 pin 4 Standby Mode Release front panel Pwr to turn OFF unit then press button in again Short PC902 pins 1 and ...

Page 39: ...wer relay must be bypassed Of course you can locate the power relay and simply add jumpers to the relay contacts There is a quicker way to bypass the power relay but it requires a very dangerous tool This tool shown in Figure 10 1 is like an extension cord only it has two male ends If this cord is ever plugged in to the AC outlet first the other end will be live and exposed Keep this tool safely a...

Page 40: ...ossover distortion Problems with the Driver amplifier cause small DC offset voltages to appear at the amplifier s 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 amplifier s output one output transistor shorted between C E As problems with the Output stages are the most common and easily found ...

Page 41: ... 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 have small DC offset voltages at the Driver amplifier output the protection circuit will be triggered and the receiver will enter the protection mode In this case change the Driver amplifier IC If that does not solve the problem check the positive and negati...

Page 42: ...lifier has a bias network problem if you still experience excessive current draw There are two methods to determine which channel is drawing current if there is any question as to which amplifier has the problem First you follow the procedure for bypassing the power switch detailed in the Overview chapter As you raise the AC line voltage you will hit a point where the current draw starts to increa...

Page 43: ... DE615 BIAS NETWORK FB OUT IN DRIVE AMP Obviously the Jumper Method is much slower but a lot safer than the Find the HOT transistor method I recommend practicing both methods as physical access limitations shift the advantage from one method to the other NOTE Service bulletin HPF0643 covers a Bias Circuit change for receiver models STRV555ES STRV444ES and STRV333ES Troubleshooting Bias Network Cir...

Page 44: ...ponents diodes or transistors in the bias network Shotgunning is preferred since intermittent bias components can cause expensive damage to the Power Amplifier While changing the active components carefully inspect all resistors and potentiometers Now it is time to verify that the unit does not draw excessive current while following the power relay bypass procedure ...

Page 45: ...unning circuits keep in mind that PNP transistors fail more frequently than any other component found in the shutdown circuit Always check PNP transistors and steering diodes for leakage When a surround sound unit is in Protect Mode the most difficult task is determining where the problem is coming from Problems can be in any one of the Power amplifiers or in the Protection circuits themselves We ...

Page 46: ...ter is pulled down by the negative B supply voltage through R1 When current flows through Q3 s E B junction Q3 turns ON When Q3 turns ON its collector will go LOW activating the Protection circuit NOTE The output transistors used in most receivers are Darlington pairs in a single package The voltage measurement across the B E junctions for a Darlington pair will be approximately 1 2V Troubleshooti...

Page 47: ...0 and Q200 the voltage drop across the resistor pairs R100 R200 and R5 R6 will also increase When the voltage drop across R6 reaches 0 6 volts Q4 will turn ON When Q4 turns ON current flowing through Q4 E C junction R4 the 15K ohm resistor D3 and R3 will pull up Q3 s base and Q3 will turn ON When Q3 turns ON its collector will go LOW activating the protection circuit Troubleshooting Method When D3...

Page 48: ...range were designed to match the audible range of human hearing they represented just one small portion of the sounds that exist in nature With the continuous progress being made in digital technology it became possible to make recordings that contained a greater volume of information allowing for further improvements in sound quality These technical developments opened the door for the creation o...

Page 49: ...dard Super Audio CD can provide space for 2 channel stereo data as well as an area for up to 6 track multi channel data and an extra data area for still pictures text data or other information both of which will be used in the near future Three disc variations are available for the Super Audio CD format The single layer Super Audio CD and dual layer Super Audio CD discs contain either one or two h...

Page 50: ...igh frequencies via a digital filter After interpolation processing at which time the data is recreated the signals are passed through a Σ modulator that converts the signals back into a 1 bit data pulse stream Additionally when recording decimated PCM data to a CD disc signals undergo 16 it 216 or 65 536 stage quantization at a sampling frequency of 44 1kHz Data exceeding this sampling frequency ...

Page 51: ...ES FOR SUPER AUDIO CD AND CONVENTIONAL CD 11 27 01 13 2A124 1393 BASE LEVEL BASE LEVEL ONE SAMPLING INTERVAL ONE SAMPLING INTERVAL BASE LEVEL SAMPLING RATE SAMPLING RATE ONE SAMPLING INTERVAL COMPARISON OF INPUT OUTPUT INPUT SINE WAVE 1 BIT QUANTIZER OUTPUT WAVE QUANTIZATION NOISE 1 0 FIGURE13 4 OUTPUT FROM 1 BIT QUANTISER 1 21 02 13 3A124 1393 DeltaSignal Σ Modulation and A D Converter As shown i...

Page 52: ...he 1 bit converter consists of 0 and 1 1 bit data This output data is analysed against the incoming signal to detect errors The error data is retarded the duration of one sample by the delay device and reintroduced to the incoming analogue signal as compensation data to be subtracted This process of continually returning error data for input to the 1 bit converter for each sample is the concept fo...

Page 53: ...quantization noise resulting from the Σ modulator is more segmented even though the original input sine wave is the same Because of the higher sampling frequency the amount of low frequency quantization noise is reduced while the amount of high frequency quantization noise is increased In reality whether the process is conducted by the Σ modulator or a 1 bit converter the volume of quantization no...

Page 54: ... enjoy even higher quality sound With future advances of this specific technology alone the broad dynamic range that so characterizes the Super Audio CD format will be even more of a reality Figure 13 8 shows a theoretical simulation of a very simplified Σ modulation system In principle it is possible to achieve an audio range and a dynamic range exceeding 120dB With DSB playback frequency charact...

Page 55: ...o feel the air The DSD system used in Super Audio CD is able to express the artistic quality of a performance like never before communicating the liveliness of the performer and the vividness of the hall Disc Features and Watermark Technology New Large Capacity Disc Thanks to the DSD format used by Super Audio CD data capacity was increased to four times that of a conventional CD using PCM Even wi...

Page 56: ...data Each Area TOC contains recorded information about the tracks included in that particular section Thanks to the combination of these two player side operation and track access become very simple With Super Audio CD disc title track title and artiste information for example can be easily displayed on the player very similar to the CD TEXT feature with conventional CD Up to 24 Music Titles and M...

Page 57: ...ty HD layer of information As mentioned previously this disc provides a 4 7Cbyte capacity There is also a dual layer disc which combines two Super Audio CDs into one disc for providing extended playback with a maximum capacity of 8 5Cbytes The third disc type is hybrid featuring an HD layer and a CD layer The layers of both the dual layer disc and the hybrid disc are 0 6mm thick Two of these layer...

Page 58: ...termark maker s discretion which is imprinted on the disc in the form of text or an image If a counterfeit disc is inserted in the Super Audio CD player the player detects the absence of the invisible Watermark and prevents playback Both types of Watermarks are almost impossible to duplicate clearly making it easy to distinguish between real and pirated discs especially for the visible Watermark w...

Page 59: ...APPENDIX ...

Page 60: ...R Center Subwoofer and Rear L R channels The output pins are as follows DATA0 pin24 is Front L R DATA1 pin23 is Center Subwoofer and DATA2 pin22 is Rear L R The Analog Stereo inputs are first digitized by the CODEC and then inputted to the DAD at SDIA1 pin85 Because this is a 2 channel signal only DATA0 pin24 Front L R will be active DATA1 and DATA2 will be inactive IC1401 Audio DSP The Front L R ...

Page 61: ...S Sony Electronics Inc EMCS A Service Company 1 Sony Drive Park Ridge New Jersey 07656 All Rights Reserved 2001 A1241201 S 01 21 02 is a trademark of Sony Electronics ...

Reviews:

No comments

Related manuals for STR-DE845

Brand: Spektrum Pages: 19

Brand: Cambridge Audio Pages: 27

FTDX5000 - SOFTWARE UPDATE INFORMATION...

Brand: Yaesu Pages: 10

Brand: Aiwa Pages: 36

Brand: Icom Pages: 32

Brand: Yaesu Pages: 42

Brand: Vitek Pages: 10

Brand: GME Pages: 12

Brand: Wonde Proud Pages: 11

UM-XSW-D0-LEN-V03-01

Brand: Swisson Pages: 16

PowerTalk Head w/ADSP & SNS 04-22

Brand: SGC Pages: 72

Brand: Vitek Pages: 20

Brand: Planet Audio Pages: 24

Brand: Strong Pages: 17

Brand: August Pages: 13

AIR-EAGLE SR L 38-2000-N

Brand: BWI Eagle Pages: 3

Brand: Kramer Pages: 17

Brand: Domain Pages: 14

Brands by name

0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Popular brands

Load more brands