2005 Pioneer Home Audio Seminar VSX49TX

Transcription

1 2005 Pioneer Home Audio Seminar VSX49TX Pioneer Electronic Service, Inc. 2005

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3 Introduction Why the VSX49TX? The VSX49TX is not current product, however it tends to be the most difficult to repair! What will be covered? The receiver in general; more specifically Display & System Micro Amplifier and Protection circuit. Power Supply DSP circuitry Trouble Shooting Tips

4 This seminar manual will be specifically about troubleshooting techniques, no operation instructions, no theory!

5 What will you get out of this? You will learn the most successful troubleshooting methods designed to get the unit on and off your bench as quickly as possible. You will learn more accurate repair techniques and avoid having to replace costly boards on out-of-warranty units. Replacing expensive boards can sometimes mean the difference between getting the repair or having the customer walk!

6 Topics we will cover Minor disassembly DSP circuitry Amplifier & Protection circuits System Microprocessor Display Microprocessor Power Supply Additional resources

7 Disassembly Remove no more than you have to! Use caution when removing the back panel screws. They are different! You are using your ESD wrist strap aren t you? ESD precautions are a fact of life! Why do your work over and over again due to static damaged components!

8 To start 1. Place unit as pictured and remove top, bottom and side covers. 2. Prop up unit as pictured for easy access. 3. Remove all screws holding the DSP boards, as well as any attached connectors or wire ties.

9 Remove only the screws necessary as shown below. Why spend more time than you have to?

10 Use caution when removing screws. There are 3 different types!

11 Keep track of the screw types. Correct place for screw with integral flat and attached star washer.

12 With the screws removed, gently pull back on the back panel, while extracting the DSP and DSP3 assemblies.

13 DSP boards removed

14 Digital Signal Processing The DSP circuit consists of 3 boards 1. AWK7719 DSP ASSY 2. AWK7727 DSP3 ASSY 3. AWK7725 DAC10 ASSY

15 DSP assemblies DAC10 ASSY #3 DSP3 ASSY #2 DSP ASSY #1

16 DSP ASSY

17 DSP3 ASSY

18 DAC10 ASSY

19 Setup DVD Digital Input either Coaxial or Optical Speaker setup 5.1 or 5 channel(without Subwoofer) Must use DVD with Surround information {Be sure to look at front panel display} For the purpose of this seminar, we will follow the left surround channel only. Indicators must illuminate for all channels driven. No illumination, no audio!

20 For your reference only Depending on the accuracy of your scope, this voltage, 5 volts (TTL level), may vary by + or -.5 volts.

21 DSP Audio Block Diagram

22 DSP Audio Circuit

23 DSP Audio Circuit continued

24 DSP Audio Circuit continued

25 DSP Audio Circuit continued

26 DSP Audio Circuit continued

27 DSP Audio Circuit continued

28 Test point DIR & DIT Pin 3 IC112 DIR & DIT Pin 3 In

29 Test point DIR&DIT IC101 Pin 3 More noise than signal IC101 Pin 3 DIR & DIT In

30 Test point DIR&DIT Pin 25 IC101 Pin 25 DIR&DIT Out

31 Test point DIR&DIT Pin 25 IC101 Pin 25 DIR&DIT Out

32 Test point Selector IC112 Pin 3 IC 112 Pin 3 Selector In

33 IC112 Pin 3 Selector In Test point IC112 Pin 3

34 Test point Selector IC112 Pin 4 IC112 Pin 4 Out

35 Test point Selector IC112 Pin 4 Test Point Pin 4 Out

36 IC301 DSP1 Pin 6 In Test point DSP1 IC301 Pin 6

37 Test point DSP1 IC301 Pin 6 Waveform very small. More noise than signal!

38 Test point DSP1 IC301 Pin 12 IC301 DSP1 Pin 12 Out

39 Test point DSP1 IC301 Pin 12

40 Test point DSP2 IC401 Pin 11 IC401 DSP2 Pin 11 In

41 Question How do I troubleshoot the DSP2 IC? It s located directly under the DSP3 ASSY. Answer.. Simply remove the DSP3 ASSY. There won t be any sound output from the unit, but you can scope the digital waveform none the less! DSP2 IC is under here.

42 Test point DSP2 IC401Pin 11 In

43 IC401 DSP2 Pin 5 Out DSP2 IC401 Pin 5 Out

44 DSP2 IC401 Pin 5 Out

45 DSP3 IC501 Pin 6 In IC501 DSP3 Pin 6 In

46 DSP3 IC501 Pin 6 In

47 DSP3 IC501 Pin 12 Out IC501 DSP3 Pin 12 Out

48 DSP3 IC501 Pin 12 Out

49 DAC10 CN6002 Pin 11 In DAC10 ASSY CN6002 Pin 11 In

50 DAC10 CN6004 Pin 10 Out DAC10 ASSY CN6004 Pin 10 Out

51 DAC10 CN6004 Pin 10 Out End of the line! Analog audio! Success!

52 Conclusion to DSP troubleshooting 1. Follow the digital signal into and out of DSP1, DSP2 and DSP3 ICs. Compare to waveforms seen in this presentation. 2. Look at the digital signal entering DAC10 ASSY. Look for analog signal to follow. 3. Loss of signal at any point requires back tracking to last good test point.

53 DSP Audio Flow Path Ideal path to follow(left Surround) JA107(DSP ASSY) IC101(DSP ASSY) IC112(DSP ASY) IC301(DSP1)(DSP ASSY) IC410(Selector)(DSP ASSY) IC401(DSP2)(DSP ASSY) CN402(DSP ASSY) CN501(DSP3 ASSY) IC501(DSP3)(DSP3 ASSY) CN501(DSP3ASSY) CN402(DSP ASSY) CN402(DSP ASSY) CN707(DSP ASSY) Continued

54 Continued DSP Path CN6002(DAC10) IC6061(DAC10) IC6303(DAC10) IC6305(DAC10) CN6004(DAC10) CN5813(MotherASSY) CN5818(Mother ASSY) CN5001(VR &Pre Out) IC5001(VR & Pre Out) IC5061(VR & Pre Out) CN5006(VR & Pre Out) CN4801(Power Amp) IC4401(Power Amp) JA4801(Power Amp) Speaker

55 DSP Socket Issues IC304 on DSP ASSY and IC504 on DSP3 ASSY. Cold solder connections on these sockets can cause loss of audio in DSP mode. For complete loss of audio, at times associated with these sockets, try resoldering socket to PCB first. At the same time, clean and coat pins of socket and IC with DeOxit, or similar compound. If this doesn t resolve the problem, remove the IC socket and solder the IC directly to the board.

56 DSP troubleshooting tips Complete loss of audio Step 1. Use Multi-Channel input jacks at rear. Step 2. Switch unit to Multi-Channel. Step 3. If audio returns, unit has a DSP ASSY problem. If still no audio, remove DSP ASSY board and repeat steps 1 and 2. If audio returns, probable cause DSP ASSY. Step 4. If unit still has no audio, probable cause is VR & PRE OUT ASSY and beyond. Step 5. To further isolate the problem, remove Main in/ Preout jumpers and insert audio directly into Main in, front channel. If still no audio, unit has amplifier problem. Don t forget to reinsert jumpers!

57 Easy tips for troubleshooting audio Loss of Analog audio Insert audio(signal Injector), or noise(put finger on Test Point to generate noise), to ensure continuation of signal past that point. Move forward or backward in the circuit as needed. Noise on Analog audio channel Use capacitor, or just short(if there is no DC voltage present) Test Point to ground at any point to silence the noise. From that point and beyond, the circuit is OK. Move forward or backwards in the circuit as needed. Please use caution and exercise good judgment!

58 Amplifier and Protection Circuit

59 Protection Circuit

60 Problem Unit shuts off Display reads AMP ERROR Probable cause Damaged amplifier components.

61 Can there be other causes? YES! How do I know if the amplifier is damaged for certain?

62 How to check for DC Offset CN5819 DC Detection, Pin 15. Should be low(0v + -.5V)in normal operation. A high(5v + -.5V) denotes DC Offset and probable Amplifier damage.

63 What if DC Offset is detected? How do I know which of the 7.1 channel(s) is bad?

64 Test points to narrow choices for DC Offset Please note: DC Offset at these Test points can only be measured when the Power Supply voltages are up to spec.

65 What if the voltage is within spec? Check these transistors for all channels. Possibly shorted!

66 None of those other parts bad? Last place to look!

67 Amplifier

68 Amplifier Failures 1. Voltage Amp Bad Voltage Amp IC. If after replacing damaged IC(s), the amplifier(s) still shows DC Offset, one or both of these resistor(s) may be open!

69 Amplifier Failures 1. Amplifier output Number 1 cause Always replace in pairs. Don t assume this is the only damage!

70 Amplifier Failures 2. Amplifier output If amplifier continues to have DC Offset after replacing output F.E.T.s, be sure to check these.1 Ohm resisters

71 System Microprocessor Basics

72 Standby Voltage On/Off RYCTRL= Relay Control Don t become confused! This output line controls the operation of the standby 5.6 V line, not the AC relays.

73 Energizing AC Relays If no DC Offset is present, Pins 58 and 60 will change state to control Port Expander IC. PIN 60 EXPOE2 Change of state enables Expander IC 1103 to allow data input. PIN 58 EXPDT2 Data output to Expander IC1103 to control AC1 and AC2 lines for AC relays.

74 Turn on signal for AC relays from Micro RAC1 & RAC2 To turn on AC Relays Tip Look for change of state Data and control lines

75 Mute Main and Multi-Room Pin 67 changes state to mute audio lines supplying MULTI-ROOM Outputs. Pin 66 changes state to mute all audio lines to MAIN amplifiers.

76 Display Microprocessor Basics

77 Turn on procedure Key Scan 1 line Key Scan in lines. Most important for Turn On, Key Scan 1. Look for low when pressing the Stand By button. This point, when statically measured, (when pushed) 14.9K Ohms to ground. IC3001

78 Communication between Micros Wake-Up output signal from IC3001, Pin 7, to input IC 5801, pin 20.

79 Volume up and down Volume up Look for change of state from high to low when turning volume up. Tip: Erratic voltage at Test point? Change Volume Encoder.

80 Volume down Look for change of state from high to low when turning volume down. Tip: Erratic voltage at Test point? Change Volume Encoder.

81 Changing inputs Look for change of state from high to low when turning the input knob to the left. Tip: Changing inputs by itself? 1. Look into bulletin SI-H04018-G.PDF 2. Change Input Encoder.

82 Changing inputs Look for change of state from high to low when turning the input knob to the right. Tip: Changing inputs by itself? 1. Look at bulletin SI-H04018-G.PDF 2. Change Input Encoder.

83 Things to keep in mind First and foremost, don t overlook the obvious! This is a very complex receiver. There are 16 fuses, A.K.A. IC Protectors, 11 regulator ICs and countless fusible resistors! There are published Tips related to nothing but blown fuses!

84 To aid in Troubleshooting First be sure the unit is not drawing more than 1.65 amps at 120 volts! Placing a short across C1002 will allow the unit to be run up slowly on a Variac.

85 Normal Condition Unit at idle, no input, no load (Note: 2.5 amp scale) 1.65 amp + or 10%

86 Note to current draw Normal current draw after settling, 1.65 amps. Note: The unit will draw in excess of 7.5 amps as you run up the AC voltage. Look for the current to drop as soon as you stop increasing the voltage. If it doesn t, pull the plug! The unit is shorted!

87 Be sure to check all regulated supplies

88 Power supply voltages CN volts Digital volts Digital volts volts volts volts Tuner volts volts

89 Power supply voltages J Ground

90 Power supply voltages J volts 2. Ground volts volts 5. Ground volts

91 Power supply voltages Very important! Stand by 5.6 volts for the microprocessor

92 Please check on our Web Site for all Tips and Bulletins when repairing any product.

93 One brief note on ESD Located on our PioneerElectronics.com website under training 5S ESD Training The importance of ESD safe practice and preparation is vital to our mutual success. It s no longer business as usual in the Digital Environment. Precautions must be taken or damage WILL occur

94 Additional resources for ESD information 1. ESDsystems.com 2. Desco.com

95 We sincerely hope you will benefit from this information. Thank you

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