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Troubleshooting Guide Overview
This troubleshooting guide is divided into three sections. The section that you use will be determined by the items available to you for use in troubleshooting. Section 1 allows for limited troubleshooting due to limited availability of items. Section 3 is the most complete troubleshooting section. Section 1: Bass Box Only Procedures is to be used if you have a bass module to troubleshoot, but no head unit or PC to turn the bass module on. It will take you through a troubleshooting process which will allow you to power up the amplifier PCB by itself, as well as some troubleshooting procedures for the Digital Signal Processor PCB, should it be at fault. Section 2: Bass Box with a Head Unit Procedures is to be used if you have a bass module and a head unit, but no PC. In this section you will be able to connect an audio signal to the head unit and turn the bass module on. This will allow you to signal trace and troubleshoot the amplifier PCB and the Digital Signal Processor PCB. Section 3: Computer Aided Troubleshooting Procedures is to be used if you have a PC that can be used to communicate with the Digital Signal Processor PCB of the bass module, and is the preferred method of troubleshooting. In this section you will be able to determine the EQ curve of the module under test as well as put the module into different test modes for easier troubleshooting. There is an Appendix at the back of this guide containing information such as simplified schematic diagrams, block diagrams, frequency response curves, tables, and computer setup information. See the table of contents for a complete listing.

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Table of Contents
Troubleshooting Guide Overview ....................................................................................................1 Table of Contents .......................................................................................................................... 2-3 Section 1, Bass Box Only Procedures....................................................................................... 4-21 Section 1 Contents ............................................................................................................................4 Test Set-up Parameters and Equipment .........................................................................................5 Bass Box Only Troubleshooting Procedures ..................................................................................5 Bass Box Only Test Procedures .................................................................................................. 6-7 Figure 1. Scope Photo of Boot Prompt at J5 Pin 11 ..........................................................................7 Amplifier PCB Hook-Up Procedures ......................................................................................... 8-11 Figure 2. Cable for Amplifier Output Connection at J701 .................................................................. 8 Figure 3. Output Wire Connection View at J701 ...............................................................................8 Figure 4. Input Wire Connection View at J700 .................................................................................. 9 Figure 5. Triac Jumping View on DSP PCB .....................................................................................10 Amplifier Test Procedures ..............................................................................................................12 DSP PCB Troubleshooting Procedures ................................................................................... 13-19 Figure 6. Codec to DSP, Digital Audio Signal Path ..........................................................................17 Figure 7. Micro to/from DSPs ..........................................................................................................17 Figure 8. DSP PCB Test Point Locations Layout Diagram, Solder Side ..........................................19 Scope Photos ............................................................................................................................ 20-21 Figure 9. Codec (U100) Scope Photo, Mute Condition ...................................................................20 Figure 10. Microcontroller (U202) Scope Photo, Power Up ............................................................21 Figure 11. Microcontroller 8 MHz clock at U202 pin 39 ...................................................................21 Section 2, Bass Module with Head Unit Procedures .............................................................. 22-41 Section 2 Contents ..........................................................................................................................22 Normal System Operation Description .........................................................................................23 Test Setup Procedures ...................................................................................................................24 Connection of Bass Module Using a CD-5/CD-20 Music Center .................................................24 Bass Box Troubleshooting Procedures ................................................................................... 25-33 Figure 12. Scope Photo of Boot Prompt at J5 Pin 11......................................................................26 Figure 13. Codec to DSP, Digital Audio Signal Path ........................................................................32 Figure 14. Micro to/from DSPs ........................................................................................................32 DSP PCB Troubleshooting ..............................................................................................................34 Figure 15. DSP PCB Test Point Locations Layout Diagram, Solder Side ........................................34 Scope Photos ............................................................................................................................ 35-41 Figure 16. Codec (U100) Scope Photo, Un-mute Condition ...........................................................35 Figure 17. Codec (U100) Scope Photo, Mute Condition ................................................................. 36 Figure 18. Microcontroller (U202) Scope Photo, Power Up ............................................................37 Figure 19. SPDIF Signal at U100 pin 42 .........................................................................................38 Figure 20. Microcontroller 8 MHz clock at U202 pin 39 ...................................................................38 Figure 21. Codec 11.2896 MHz Clock ............................................................................................39 Figure 22. 40 MHz DSP clock .........................................................................................................39 Figure 23. 3.3V Switching Power Supply Signals............................................................................40 Figure 24. Power Up Condition at U202 Pin 25 ...............................................................................40 Figure 25. Transmit Frame Sync .....................................................................................................41 Figure 26. Serial Data Clock ...........................................................................................................41 Figure 27. Audio Data .....................................................................................................................41 Section 3, Computer Aided Troubleshooting .......................................................................... 42-64 Section 3 Contents ..........................................................................................................................42 Test Setup Parameters and Equipment .........................................................................................43 Test Setup Procedure .....................................................................................................................43 2

Table of Contents (continued)
Troubleshooting Procedures ................................................................................................... 44-57 Figure 28. 25 Pin to 9 Pin Serial Data Cable...................................................................................44 Figure 29. DSP PCB Test Point Locations Layout Diagram, Solder Side ........................................44 Figure 30. Scope Photo of Boot Prompt at J5 Pin 11......................................................................47 Figure 31. Codec to DSP, Digital Audio Signal Path ........................................................................56 Figure 32. Micro to DSPs ................................................................................................................56 Scope Photos ............................................................................................................................ 58-64 Figure 33. Codec (U100) Scope Photo, Un-mute Condition ...........................................................58 Figure 34. Codec (U100) Scope Photo, Mute Condition ................................................................. 59 Figure 35. Microcontroller (U202) Scope Photo, Power Up ............................................................60 Figure 36. SPDIF Signal at U100 pin 42 .........................................................................................61 Figure 37. Microcontroller 8 MHz clock at U202 pin 39 ...................................................................61 Figure 38. Codec 11.2896 MHz Clock ............................................................................................62 Figure 39. 40 MHz DSP clock .........................................................................................................62 Figure 40. 3.3V Switching Power Supply Signals............................................................................63 Figure 41. Power Up Condition at U202 Pin 25 ...............................................................................63 Figure 42. Transmit Frame Sync .....................................................................................................64 Figure 43. Serial Data Clock ...........................................................................................................64 Figure 44. Audio Data .....................................................................................................................64 Appendix .................................................................................................................................... 65-87 Computer Setup Procedure ..................................................................................................... 65-66 Figure 45. Test Setup Diagram ........................................................................................................68 Figure 46. Fault Circuits ..................................................................................................................69 Figure 47. DSP PCB and Amplifier PCB Interconnection Diagram .................................................70 Figure 48. DSP PCB Basic Block Diagram ..................................................................................... 71 Figure 49. DC Power Supplies Simplified Schematic Diagram .......................................................71 Figure 50. Protection Circuit Simplified Schematic Diagram ...........................................................72 Figure 51. Microcontroller U202 Basic Block Diagram ....................................................................73 Figure 52. Satellite Amplifier DC Offset Detector Simplified Schematic Diagram ...........................73 Figure 53. Analog Signal Path from Input Jacks to Codec Simplified Schematic Diagram .............74 Figure 54. Digital Signal Path from Input Jack to Codec Simplified Schematic Diagram ................74 Figure 55. Analog Signal Path from Codec to Satellite Simplified Schematic Diagram ...................75 Figure 56. Transformer Wiring Diagram .......................................................................................... 75 Figure 57. Digital Bass Module Overall Turn-on Circuit Schematic Diagram .................................. 76 Figure 58. Lifestyle® 12 and 25 Series II Overall Frequency Response Curve ...............................77 Figure 59. Lifestyle® 30 Series II Overall Frequency Response Curve ...........................................77 Figure 60. Lifestyle® Series II Tone Control Frequency Response Curve .......................................78 Figure 61. Lifestyle® Series II Film EQ Frequency Response Curve ..............................................78 Figure 62. Lifestyle® Series II Dynamic EQ Frequency Response Curve .......................................79 Figure 63. Lifestyle® Series II 240 Volt Bass Frequency Response Curve ......................................79 SPDIF ................................................................................................................................................80 TTL to RS232 Converter .................................................................................................................80 TAP Commands ......................................................................................................................... 80-81 Hex Notation ....................................................................................................................................82 Firmware CHECKSUMS ..................................................................................................................82 Diagnostic voltages available at the uC ADC ports .....................................................................83 Two digit hex to voltage conversion ........................................................................................ 83-86 Thermistor readings (TAP command "ad2") ........................................................................... 86-87

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Section 1 Bass Box Only Procedures
Section 1 Contents
Section 1, Bass Box Only Procedures....................................................................................... 4-21 Test Set-up Parameters and Equipment .........................................................................................5 Bass Box Only Troubleshooting Procedures ..................................................................................5 Bass Box Only Test Procedures .................................................................................................. 6-7 Figure 1. Scope Photo of Boot Prompt at J5 Pin 11 ..........................................................................7 Amplifier PCB Hook-Up Procedures ......................................................................................... 8-11 Figure 2. Cable for Amplifier Output Connection at J701 .................................................................. 8 Figure 3. Output Wire Connection View at J701 ...............................................................................8 Figure 4. Input Wire Connection View at J700 .................................................................................. 9 Figure 5. Triac Jumping View on DSP PCB .....................................................................................10 Amplifier Test Procedures ..............................................................................................................12 DSP PCB Troubleshooting Procedures ................................................................................... 13-19 Figure 6. Codec to DSP, Digital Audio Signal Path ..........................................................................17 Figure 7. Micro to/from DSPs ..........................................................................................................17 Figure 8. DSP PCB Test Point Locations Layout Diagram, Solder Side ..........................................19 Scope Photos ............................................................................................................................ 20-21 Figure 9. Codec (U100) Scope Photo, Mute Condition ...................................................................20 Figure 10. Microcontroller (U202) Scope Photo, Power Up ............................................................21 Figure 11. Microcontroller 8 MHz clock at U202 pin 39 ...................................................................21

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Test Set-up Parameters and Equipment
Use the disassembly/assembly procedures found in the AM25/30P Series II service manual part number 199401, to access the PCBs. Speaker Output Loading: Unless testing the amplifier for its rated power output, all tests are to be performed with the speaker outputs unloaded. The amplifier can be tested with loads as long as the PCB is still mounted in its heatsink. Left Front Output: Right Front Output: Center Output: Left Surround Output: Right Surround Output: Bass Channel Output: Equipment Requirements: Test Cable part number 199527 Test Set-up 1. Set up the bass box as shown in the Test Setup Diagram, (Figure 45. in the Appendix) Note: Since you have only the bass box for troubleshooting and are not using a PC to communicate with the module, you will not use the connectors for the PC, the audio jacks or the digital input jack on the test cable. You will use the 3.5mm mono jack and the 9 Volt battery to turn the module on. When the module is powered on using the battery or a DC power supply, it will come up with the amplifiers muted. You will not be unmuting the amplifiers and passing an audio signal while performing the tests in this section. If the module passes the tests in this section, you can use the amplifier test procedures to test the amplifier board on its own and verify that it is okay. 8 Ohm, 1%, 50W 8 Ohm, 1%, 50W 8 Ohm, 1%, 50W 8 Ohm, 1%, 50W 8 Ohm, 1%, 50W 4 Ohm, 1%, 100W

Bass Box Only Troubleshooting Procedures
1. Module Power-up 1.1 With the top cover removed and the line cord connected to an AC mains source, connect the 9 Volt battery to the 3.5 mm mono plug, TIP (+) RING (-), located on the test cable. This will power up the module. Note: If you disconnect AC mains from the module, you will need to disconnect and reconnect the 9 Volt battery to the 3.5 mm plug to get the module to power up again. 2. Check for Voltage at the Transformer 2.1 Check for voltage at the transformer secondary. If there is voltage at the transformer secondary, skip to procedure 4. If there is no voltage on the transformer secondary, continue on to step 2.2. 5

Bass Box Only Test Procedures
2.2 Check for AC mains voltage, 120 or 240 VAC at the transformer primary. If there is voltage at the transformer primary, remove AC mains power and check the thermal fuse in the transformer primary. Replace the transformer if the internal fuse is open. If there is no voltage at the transformer primary, proceed as follows. 2.2.1 Check the fuse located on the PCB. 2.2.2 Ensure that the 18 conductor ribbon cable is fully seated. 2.2.3 With the line cord connected, connect the 10V turn-on signal to the 3.5 mm mono plug located on the test cable. Check the voltage at U300 pin 1. If it is ~1.25 VDC, U300 should be on, turning triac D302 on. Go to procedure 4. If it is ~0.8 VDC, the opto-coupler U300 is crowbarred off keeping triac D302 off, which connects AC mains voltage to the transformer primary. Disconnect power to the bass module and go to procedure 3. 3. U300 Crowbarred Off, Triac D302 Off Note: Refer to Figure 50. Protection Circuit Simplified Schematic Diagram in the Appendix for an overview of the protection circuit. 3.1 If the bass module crowbars off (shuts off) immediately (<50 msec) after applying the 10V turn-on signal, check the "protect" signal at J8 pin 6. If the voltage on J8 pin 6 is greater than approximately +0.7 VDC, it will turn on Q202 and if the voltage is less than approximately -0.7V, it will turn on Q203. Turning on either Q202 or Q203 causes Q202 and Q203 to latch and this will activate the crowbar. If there is a fault condition at J8 pin 6, check the ±12 VDC, ±17 VDC and ±34 VDC power supplies. If the ±12 VDC power supply is not working and the ±34 VDC power supply is working, check resistive fuses R714 and R713 located on the amplifier PCB. A failed component could be causing one or more of these supplies to sag, causing the unit to crowbar off. If the DC power supplies are working, continue onto step 3.2. 3.2 DC offset at the output of the bass amplifier J703 pin 2 (+) and pin 1 (-) will produce a fault condition `protect" voltage (greater than approximately ± 0.7 VDC) at J8 pin 6. Check the components in the bass amplifier with an Ohmmeter. 3.3 If the bass module crowbars off after approximately 3 seconds, there could be DC offset on one or more satellite outputs. The satellite outputs are summed through the "speaker output DC offset" circuit (SD251571, grid location A7). The output of this circuit, P66, is sent to the microcontroller U202 pin 25. In normal operation, the voltage at U202 pin 25 should be 2.5 VDC. If the voltage strays more than 1 VDC from the normal 2.5 VDC, microcontroller U202 pulls pin 39 (P22) to ground (normally high impedance) pulling R308 to ground latching the circuit consisting of Q302 and Q303 (SD251571, grid location B4). This latch circuit, when latched, will shut off the opto-isolator U300, which will shut off the triac D302 disconnecting AC from the primary of the transformer. Note: U202 pin 26 is connected to U202 pin 39. The head unit does not send an "ON" command to the bass module. The uC knows when the power has just come up by watching the status of the 10V turn-on voltage via pin 26, which is connected to the same circuit mentioned above that the uC uses to shut down the triac. 3.4 If everything checks out up to this point and the bass module is not crowbarred off, then go to procedure 4.

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Bass Box Only Test Procedures
4. Microprocessor Circuit Check 4.1 The serial data output leaves the DSP PCB at J5 pin 11 (U202 pin 43, signal name "TTY OUT") and the boot prompt can be checked here at power-up with an oscilloscope. The first thing the uC is supposed to do when it comes out of reset is to print the following to the "debug" output J5 pin 11. ** %0001#01 This is visible as two bursts of activity. One immediately following the rising edge of the RESET line (**) and one about 50 msec later (%0001#01). After printing the boot prompt, the uC will only print error codes. Thus, a lack of activity on this signal after the initial two bursts is expected. Short bursts of activity is likely to be the uC printing out an error code. Refer to Figure 1.

Upper trace: RESET (active low) pulse U202 pin 14 or U200 pin 2 Middle trace: +5V supply Lower trace: Serial data from uC, J5 pin 11 Figure 1. Scope Photo of Boot Prompt at J5 Pin 11 4.2 If there is no boot prompt at U202 pin 43, then check for the following; +5 VDC at U202 pin 40 and U202 pin 18, 8 MHz clock on both sides of X600, reset pulse at power-up at U202 pin 14. If the +5 VDC, 8 MHz clock and reset pulse are okay and there is no boot prompt, then the uC has failed. Replace the uC U202. 4.3 If everything looks okay up to this point, you can go to the amplifier hookup procedures and the amplifier test procedures to test the amplifier board on its own if you suspect it is the problem. If you suspect the DSP board, you can go to the DSP troubleshooting procedures to further troubleshoot the DSP board, or you can send it in for repair or replacement. 7

Amplifier PCB Hook-Up Procedures
This procedure will allow you to connect and operate the amplifier PCB by itself, with no DSP board connected. This will enable you to determine whether the amplifier PCB or the DSP PCB is defective. If you can turn the the amplifier PCB on, and perform the test procedures later in this section, then the amplifier PCB should be fine and the DSP board is most likely at fault. You can isolate the failure on the DSP board further using the DSP troubleshooting procedures later in this section. Below is a picture of the cable for the audio outputs on the amplifier PCB which will be connected to J701 on the amp PCB. This cable can be built using the interconnect cable, Bose® part number 190701-001, and soldering wires to the connector end.

Figure 2. Cable for Amplifier Output Connection at J701

Figure 3. Output Wire Connection View at J701

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Amplifier PCB Hook-Up Procedures

Figure 4. Input Wire Connection View at J700 1. Remove the top cover assembly using the disassembly/assembly procedures located in the service manual part number 199401. The first PCB board you see is the DSP PCB (it has a shield on it). Disconnect the gray interconnect cable from the top PCB. Disconnect the white ribbon cable from the bottom PCB (amplifier board). 2. Connect individual 22 AWG, solid core wires to connector J700 at the L/R/C/LS/RS output jack. This is the location where the white ribbon cable was connected. Connect the 8-wire test cable (see Figure 2) to the 8-wire gray cable coming from the amplifier PCB. Refer to Figure 4 and the Input Connector Table on page 11 for the following instructions. Connect a wire to pins 2, 3 and 4 of the connector J700. These are the mute lines used for un-muting the amplifier outputs. Connect individual wires to pins 12 (right channel), 10 (left channel), 9 (center channel), 8 (bass channel), 7 (left surround) and 6 (right surround). Leave the woofer connector where it is. You should connect the wires one channel at a time. Connect a single wire to pin 11 for a signal ground and connect a jumper wire from the audio signal ground to the shield on the DSP PCB.

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Amplifier PCB Hook-Up Procedures
3. Jumper point A to point B on the PCB as shown in Figure 5 below. Point A is the fuse clip and Point B is J7 pin 1. There are two versions of the Triac, one is a through hole device and the other is a surface mount device. This procedure will work with either version. 4. Connect an oscilloscope to the pair of wires for the channel under test as wired in step 2. Refer to the Output Connector Table on page 11 for the for a listing of the correct pair of wires to test the channel desired (L, R, C, LS or RS). 5. Apply a 250 Hz, 63 mVrms signal to the input wires connected in step 2, and connect the audio signal generator ground to pin 11 and the shield. 6. Apply AC mains voltage to the AC input jack. Be careful around the connector J7 on the top PCB. This connector has the line voltage on it. 7. Connect a +5 Volt DC supply to connector J700 pins 2, 3 and 4 (+5 volt mute lines). This will unmute the amplifiers. 8. At this point you should be able to hear audio coming out of the bassbox and/or see a sinewave on the oscilloscope. Check all of the outputs. If you can pass an audio signal through all six outputs, check the outputs at the ribbon cable at J701 with a satellite speaker (or an 8 Ohm load). Using the Amplifier Test Procedures on page 12, check each of the outputs for proper operation. If all channels are operating to specification with the loads according to the test procedures then you can assume the DSP PCB to be defective. 9. At this point, you can go to the DSP PCB troubleshooting procedures, or replace the DSP PCB. 10. If there is no output from the satellite or bass channels, then you will need to troubleshoot the amplifier PCB.

Figure 5. Triac Jumping View on DSP PCB 10

Amplifier PCB Hook-Up Procedures
Input Connector Table

J700 Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Pin 9 Pin 10 Pin 11 Pin 12 Pin 13 Pin 14 Pin 15 Pin 16 Pin 17 Pin 18

Description Not used Logic signal +5Volts Logic signal +5Volts Logic signal +5Volts Left and right audio return Right surround audio input Left surround audio input Bass audio input Center audio input Left audio input Input ground reference Right audio input Protect -12 Volts Input ground reference +17 Volts (fused) Input ground reference +12 Volts
Output Connector Tables

Note

J701 Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8

Description Center channel audio return Left audio output Center audio output Right audio output Left and right audio return Right surround audio return Left/right surround audio return Left surround audio output

Note

J703 Pin 1 Pin 2

Description Bass audio return Bass audio output

Note

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Amplifier Test Procedures
Note: Unless you are testing the amplifier for its rated power output, all tests are to be performed with the speaker outputs unloaded. The amplifier can be tested with loads as long as the PCB is still mounted in its heatsink. Speaker Load Table

Output Bass Channel output Left Channel output Right Channel output Center Channel output Left Surround output Right Surround output
1. Bass Channel Gain Test

Location J703 pin 2 +, J703 pin 1 J701 pin 2 +, J701 pin 5 J701 pin 4 +, J701 pin 5 J701 pin 3 +, J701 pin 1 J701 pin 8 +, J701 pin 7 J701 pin 6 +, J701 pin 7 -

Recommended Load 4 Ohm, 1%, 100 Watts 8 Ohm, 1%, 50 Watts 8 Ohm, 1%, 50 Watts 8 Ohm, 1%, 50 Watts 8 Ohm, 1%, 50 Watts 8 Ohm, 1%, 50 Watts

1.1 Apply a 200 mVrms, 300 Hz signal to the input wires for the bass channel input at connector J700 pins 8 (signal) and 11 (ground). Also ground pin 11 to the shield. 1.2 Reference a dB meter to the input. Measure the gain at the output. It should be +21.5 dB ± 2 dB. 1.3 Change the input signal to 20 Hz. Reference a dB meter to the input. Measure the gain at the output. It should be +21.5 dB ± 2 dB. 2. Left, Right, Center and Surround Channel Gain Test 2.1 Apply a 200 mVrms, 100 Hz signal to the input wires on connector J700 pins 6 (RS), 7 (LS), 9 (C), 10 (L), 12 (R) and pin 11 (ground). 2.2 Reference a dB meter to the input. Measure the gain at the output of each channel. It should be +11.5 dB ± 2 dB. 2.3 Change the input signal to 15 kHz. Reference a dB meter to the input. Measure the output of each channel. It should be +11.5 dB ± 2 dB. 3. Bass Channel Distortion Test 3.1 Connect a 4 Ohm load to the Bass channel output at J703 pins 1 (-) and 2 (+). 12

3.2 Apply a 100 mVrms, 100 Hz signal to the input wires for the bass channel input at connector J700 pins 8 (+) and 11 (-). 3.3 Measure the distortion at bass channel output. It should be <0.4% at 0.5 Watts output. 3.4 Change the input level to 1.35 Vrms. 3.5 Measure the distortion at the bass channel output. It should be <0.3% at 65 Watts output. 4. Left, Right, Center and Surround Channel Distortion Test 4.1 Connect each of the outputs to an 8 Ohm load. Apply a 533 mVrms, 1 kHz signal to the input wires at connector J700 pins 6, 7, 9, 10, 12 and 11. 4.2 Measure the distortion at the outputs. It should be < 0.3% at 0.5 Watts output. 4.3 Change the input level to 4.1 Vrms. 4.4 Measure the distortion at the outputs. It should be < 0.3% at 30 Watts output. 5. DC Offset Test 5.1 Disconnect all loads. Ground all audio inputs and apply a 5 Volt DC signal to the mute lines pins 2, 3 and 4. 5.2 Measure the DC offset on all the outputs, it should be < 20 mVdc.

DSP PCB Troubleshooting Procedures
DSP PCB Troubleshooting Procedure Setup 1. Remove all test cables used in the amplifier test procedures, if necessary, and reassemble the electronics module, leaving the top cover off. Refer to the Digital Bass Box service manual, Bose® part number 199401 for disassembly/assembly procedures. 2. Using the test cable, part number 199527, connect the module as shown in Figure 45. Test Setup Diagram shown in the appendix. Using this setup, the amplifiers will not be un-muted, so you won't be able to pass an audio signal through the module, but the voltages and signals shown in the DSP troubleshooting section will be present. You will not be connecting a PC or an audio or digital signal source. You will use the 3.5mm mono jack and a 9 Volt battery to turn the module on after applying AC mains power through the power cord. Note: If you disconnect AC mains from the module, you will need to disconnect and reconnect the 9 Volt battery to the 3.5 mm plug to get the module to power up again. 1. Quick Check/Possible Problems With DSP PCB 1.1 Because the DSP IC's legs are very fine, there is a chance for shorts or opens. Probing can result in shorting them. Boot data can be garbled due to a short or open on the DSP IC pins. 1.2 The 40 MHz oscillator, CR400, might not be working. 1.3 There might be a broken "via" in the PCB. This is a hole in the PCB that connects traces on the top side of the PCB to traces on the bottom side of the PCB. This type of problem can be difficult to isolate. 1.4 If the problem has not been isolated, go to procedure 2. Note: Refer to Figure 8. DSP PCB Test Point Locations Layout Diagram, Solder Side on page 19 for the following procedures. 2. Miscellaneous DSP PCB Troubleshooting Tips 2.1 +17V, ±12V Power Supplies The PCB draws power from three different supplies: 2.1.1 +17V unregulated, at about 250 mA when everything is running normally. The +17V supplies the unregulated voltages for the two voltage regulators on this PCB: the +5V linear regulator U1, and the 3.3V switching regulator U500. The +17V is brought onto the PCB from J8 pin 3. Note that the +17V unregulated supply can vary from about +17V to as low as +10V, depending on conditions. On the bench, the value may be more typically +15V or so. Whatever the exact voltage, in this document it will be referred to as the "+17V" supply. 2.1.2 ±12V, at about 40 mA or so. The ± 12V supplies are for the op-amps U103 -- U105. +12V is brought onto the PCB from J8 pin 1, and -12V is supplied from J8 pin 5. 2.2 +5V Supply Check the +5V supply first, since the +5V powers the microcontroller and without it, nothing else works. Check the following points: 13

DSP PCB Troubleshooting Procedures
2.2.1 At the input side to the +5V regulator U1. This is a typical 7805 3-terminal linear regulator, so it needs at least 7.5V at the input to stay in regulation. If there is +17V at J8 pin 3, but no voltage at the input side of U1, check the components in between (R10 and R11, large SMD resistors on the bottom side). 2.2.2 At the output side of the +5V regulator. Check that the 5V output is clean and that the regulator is not oscillating. The regulated +5V is supplied to the rest of the PCB via a couple of filter components, so check for +5V at the following points: 2.2.3 U102 pin 20; if no +5V here, check L200 (bottom side, between U101 and U104). 2.2.4 U100 pin 40; if no +5V here, check both L2 (top side, near U100 pin 20) and L1 (bottom side, directly under U100). 2.3 8 MHz Clock The micro requires an 8 MHz clock to run. This clock is developed by an internal oscillator which requires an external ceramic resonator (X600). Check for the 8 MHz clock at: 2.3.1 Ceramic resonator X600 (top side, next to U202). There should be a roughly sinusoidal waveform, 0V to 5V, on both sides of X600. See Figure 51 in the Appendix. If there is no 8 MHz clock, possible causes are: · No +5V; check L200. · Poor soldering If the 8 MHz clock is present at X600, and its amplitude is roughly 5Vpp, but the microcontroller won't issue a boot prompt or turn on the 3.3V power supply, possible causes are: · Dead micro. · A missing RESET pulse at power up. Power the board down and back up again, and verify that the micro is getting a healthy RESET pulse at power up. The reset IC (U200, SOT-23 bottom side) should hold the micro's RESET input (pin 14) low for about 250 msec after the +5V supply has stabilized. The RESET input should transition from low to high cleanly and briskly. If it appears to be floating, check R280. 2.4 3.3V Supply The 3.3V supply is supplied by the switching regulator IC U500. This IC works by rapidly switching its output between +17V and ground; the output filter (L500 and C500) blocks the 100 KHz switching waveform and passes only the average 3.3 VDC. Note that the micro can turn U500 on or off, via one of its output ports (U202 pin 41) and Q500. U500 powers up off with its "soft-start" node (pin 19) clamped to ground, which inhibits operation, and it remains in this state until the micro boots successfully and pulls the base of Q500 to ground. The point to remember is that the 3.3V supply does not power up until after the micro boots successfully. Assuming that the micro does boot successfully, check U500 for the following waveforms at the following points: 2.4.1 +17V on both sides of the surface-mount inductor L501 (top side). 2.4.2 5.1 VDC at U500 pin 18. This is a reference voltage generated by U500. Its presence here on pin 18 will show that U500 is getting power. 14

DSP PCB Troubleshooting Procedures
2.4.3 Check that U500 pin 11 is connected to ground. This pin is U500's ENABLE input; if it isn't grounded, U500 shuts down. 2.4.4 Check that the base of Q500 (bottom side) or U202 pin 41 (same node) is pulled to ground. If Q500 is turned on, U500 shuts down. This node is pulled up to +5V with R282 (sheet 2); the micro pulls this node low after it boots. If the micro doesn't boot, U500 never turns on. 2.4.5 100 KHz switching waveform on the +17V side of the toroidal inductor L500. This waveform should switch rapidly (<100 nsec) between about -0.35V and VCC, with an average DC voltage of 3.3V, Figure 40. If the voltage at this node dips well below -0.35V, then check D500 (bottom side). 2.4.6 If still no luck, check L500. If it's a toroidal inductor, check that it's properly soldered to the PCB. 2.5 11.2896 MHz Codec Clock If the micro and DSP appear to have booted properly, check the codec U100 for signs of health. The codec does not power up in a useful state all by itself; the micro must program a number of internal registers via the I 2 C buss inputs to the codec . (I 2 C is a 2 wire serial buss; one line for the data, one line for the clock.) To quickly determine if the codec was properly initialized by the micro, check for; 2.5.1 0V -- 5V, 11.28 MHz sine wave on both terminals of the crystal CR100. If the 11.28 MHz clock, Figure 38, is not oscillating, possible causes might be: · No +5V power to the codec U100. Check both power pins (19 and 40). If there's power on one but not the other, check L1 and R3 (bottom side, directly under U100). · I 2 C data or clock signals missing. Check for digital activity (0V -- 5V) on these signal paths: U202_32 -- R253 -- U100_4 U202_33 -- R265 -- U100_3 Once the micro boots, there is a fair amount of regular activity on these two lines. The micro checks the codec's error status register about every 5 msec , so if these lines are silent, suspect a bad micro or a broken connection somewhere in between the micro and the codec. Also, the micro will output an error code if it detects an on going problem with the I 2 C. · A problem in the network of components around CR100, R175, R176, C139, C140. Check CR100 · Codec power-down input at pin 8. Normally, this signal is pulled up for proper codec operation. When this pin is low, the codec enters a low-power reset state. The micro will pulse this line low for a few msec to reset it prior to initialization. If this line is held continuously low for some reason, the codec's oscillator won't operate, and the analog reference voltage (about 2.3V) at pin 16 disappears. If the 11.28 MHz codec clock is oscillating, then verify the following digital output signals from the codec: 2.5.2 Bit clock at R186, U100_38: 11.2896 MHz square wave 2.5.3 Frame clock at R185, U100_37: 44.1 KHz square wave 15

DSP PCB Troubleshooting Procedures
2.5.4 Output data, U100_36: "irregular" digital activity at R187, similar to Figure 44. 2.6 Codec Revision Code The CS4226 codecs must be rev. G or higher. Specifically, the rev. code must NOT be "C". The rev. letter is the letter immediately preceding the date code silkscreened on the IC, e.g. CRYSTAL (logo) CS4226-KQ EP (part number) JTAAXG9819 (rev. G, date code 9819 [19th week of `98]) 2.7 DSP 40 MHz Clock 2.7.1 The DSPs run on a 40 MHz clock; the easiest place to check for this is at J401_4 (J401 is the un-loaded 14-pin connector between DSP2 and the shield fence). This is a buffered version of the 40 MHz clock that drives the DSP. This clock has very fast edges (3 nsec rise times), so if you're using a low-quality scope probe, don't be too alarmed by what you see. A cheap scope probe or a long or missing ground lead will distort this signal beyond recognition. In this case, it's ugly, but it's not a serious issue, all you're trying to do is verify that the clock is oscillating. However, pay attention to the frequency, this is a third overtone oscillator, which means it may prefer to oscillate at 13.333 MHz (40/3). If the network of components around CR400 is incorrect in some way, it may prefer to oscillate at some frequency unrelated to what's printed on the crystal. 2.7.2 40 MHz clock frequency at U104 pin 4: 40 MHz If there's no 40 MHz clock at all: · Check U400 (LCX00) for proper soldering, and check for 3.3V on U400_14. · Check to make certain that all the components around the crystal (C402, C403, R411, R412, R409 -- bottom side, under CR400) are OK. 2.8 DSP Reset Pulse Check for a clean reset DSP reset pulse at the collector of Q200 (top side, near U102). At powerup, Q200 is biased on, driving the collector low, until the micro boots properly. After the micro boots, it turns Q200 off and allows the DSP reset line to be pulled high. This signal is digital, and should be either at 0V or at 3.3V. 2.9 Digital One-shot U106 U106 is a flip-flop wired up to produce a narrow pulse on the falling edge of the 44.1 KHz clock. Without the signal that this IC produces, the DSP can't send or receive from the codec properly. Inputs to U106: 2.9.1 U106 pin 1: 44.1 KHz clock 2.9.2 U106 pin 5: 11.28 MHz clock 2.9.3 Output from U106 pin 13: 100 nsec pulse, at 44.1 KHz rate, similar to Figure 42.

16

DSP PCB Troubleshooting Procedures
2.10 5V / 3.3V Level Translators The micro (U202) and the codec (U100) run on +5V, while the DSPs run on 3.3V. There are a couple of level-translator ICs required to bridge this gap: U101, a 74LCX244, a 3.3V part which has "5V tolerant" inputs. U102, a 74ACT244, a 5V part with input logic thresholds that are compatible with 3V logic ("TTL", or 0.8V/1.5V). Since there's a problem somewhere on the PCB, it isn't safe to assume that you'll be able to observe any digital activity on the pins listed below, although normally there would be. Mainly what we're looking for is evidence that a buffer gate isn't buffering; i.e., a signal is present on the input, but there's no similar signal on the output. From the codec U100 to DSP1: U101_13 --> U101_7 U101_15 --> U101_5 U101_17 --> U101_3 From DSP1 to the codec U100 U102_2 --> U102_18 U102_4 --> U102_16

5V
U100 SDIN1 CS4226 codec 36 SDOUT1 SCLK LRCLK 38 37 34 16 4

5V
18

3V 2

DSP1

DSP2
83 84 85 80 DTO 81 TCLKO 82 TFSO

U102

73 DT1 TCLK1 TFS1

DRO RCLKO RFSO

DR1 RCLK1 RFS1

76 77

3V
13 15 17 7 5 3

3V
DTO TCLKO TFSO 80 81 82 83 84 85 DRO RCLKO RFSO DT1 TCLK1 TFS1 72 73

75 76 77

DR1 RCLK1 RFS1

1

5
1 shot

10 U101

U106

Figure 6. Codec to DSP, Digital Audio Signal Path
U101

From the micro to DSP1: U101_4 --> U101_16 U101_2 --> U101_18 From DSP1 to the micro: U102_15 --> U102_5 U102_17 --> U102_3 From the micro to DSP2: U101_8 --> U101_12 U101_6 --> U101_14 From DSP2 to the micro: U102_11 --> U102_9 U102_13 --> U102_7
5V
Uc U202

8 7 6 5

4 2 5 3

16 18 15 17 U102 U101
3V

DSP1

12 11 10 9

8 6 9 7

12 14 11 13 U102
3V

DSP2

Figure 7. Micro to/from DSPs 17

DSP PCB Troubleshooting Procedures
2.11 Evidence that the DSPs have booted 2.11.1 DSP Output Ports Observe the following signals as the power to the PCB comes up: U102_15 U102_11 These signals are part of the communications buss between each DSP and the microcontroller, and are pulled up to +3.3V by resistors. One of the very first things that either DSP will try to do is talk to the micro, which initially requires pulling these signal lines low. If DSP1 is working, U102_15 will show some activity about 100 msec after the 3.3V supply comes up. If DSP2 is working, U102_11 will show some activity about 100 msec after the 3.3V supply comes up. If these signals power up to 3.3V and sit there doing nothing, then one or both of the DSPs failed to boot. 2.11.2 Boot Activity on External Address Buss The DSPs have no internal program ROM, and must boot from the external PROM. The boot happens in two stages. First, a short (256 words) boot loader program is loaded automatically; second, the boot loader program is executed. Typically, the boot loader program loads the other 99% percent of the PROM contents into the DSPs. The first stage of the boot is hard-wired into the DSPs, so as long as the DSPs have power, a 40 MHz clock, and a few other signals, the first stage of the boot always happens when the reset line goes high. However, the second stage happens only if the boot loader program actually works, which of course it won't if the DSPs are trying to boot from an empty or damaged PROM, or if the data lines or address lines between the PROM and the DSPs are shorted together. Observe the activity on PROM pin 30 at power-up. A successful boot will show a flurry of activity about 30 msec long immediately following the release of the DSP reset line (collector of Q200). An unsuccessful short boot won't last more than 300 usec. If it becomes clear that the DSPs aren't booting, the problem might be caused by: · Solder problems affecting the fine pitch leads on the DSPs. This is the most common source of DSP boot errors. Examine the leads of each DSP under an illuminated magnifying glass, checking for shorts (which are usually pretty easy to see) and opens (which sometimes are not). · Solder problems affecting the 4 resistor r-packs. These are attached to some critical DSP buss signals, so a loose connection here can cause problems.

18

DSP PCB Troubleshooting Procedures

Figure 8. DSP PCB Test Point Locations Layout Diagram, Solder Side 19

Scope Photos
The bass module is muted when it is first powered up and will not un-mute until it receives an "un-mute" or "volume up" command. Muted data consists of all zeroes; this condition is shown in the lower trace of the codec (U100) scope photo, mute condition.

Upper trace: LR_CLK (U100 pin 37) 44.1 kHz square wave Middle trace: SDOUT1 (U100 pin 36) serial data out Lower trace: SDIN1 (U100 pin 34) serial data in Figure 9. Codec (U100) Scope Photo, Mute Condition The significance of the SDOUT1 signal (U100 pin 36) is that it represents the digital audio data at the start of the digital audio signal path. This data is transmitted serially to the DSP1, which requires three signals to accept it: SCLK (U100 pin 38): to clock the serial data in LRCLK (U100 pin 37): to indicate the start of each audio sample SDOUT1 (U100 pin 36): the serial audio data The significance of the SDIN1 signal (U100 pin 34) is that it represents the output of the digital audio signal chain. The data is shifted out from DSP2 using the clock signals mentioned above. If this signal is dead, DSP2 is most likely not running. See Figure 44.

20

Scope Photos

Figure 10. Microcontroller (U202) Scope Photo, Power Up Upper trace: RESET pulse (active low), U202 pin 14 or U200 pin 2 Middle trace: +5V supply Lower trace: Serial data from uC, J5 pin 11 The first thing the microcontroller supposed to do when it comes out of reset is to print the following to the debug output J5 pin 11. ** %0001#01 This is clearly visible as two bursts of activity (4800 BAUD), one immediately following the rising edge of the reset line ( ** ) and one approximately 50 msec later (%0001#01). After printing the boot prompt, the Uc will only print error codes. Thus, a lack of activity on this signal after the initial two bursts is expected. Short bursts of activity is likely to be the uC printing out error codes.

Figure 11. Microcontroller 8 MHz clock at U202 pin 39 21

Section 2 Bass Module with Head Unit Procedures
Section 2 Contents
Section 2, Bass Module with Head Unit Procedures .............................................................. 22-41 Normal System Operation Description .........................................................................................23 Test Setup Procedures ...................................................................................................................24 Connection of Bass Module Using a CD-5/CD-20 Music Center .................................................24 Bass Box Troubleshooting Procedures ................................................................................... 25-33 Figure 12. Scope Photo of Boot Prompt at J5 Pin 11......................................................................26 Figure 13. Codec to DSP, Digital Audio Signal Path ........................................................................32 Figure 14. Micro to/from DSPs ........................................................................................................32 DSP PCB Troubleshooting ..............................................................................................................34 Figure 15. DSP PCB Test Point Locations Layout Diagram, Solder Side ........................................34 Scope Photos ............................................................................................................................ 35-41 Figure 16. Codec (U100) Scope Photo, Un-mute Condition ...........................................................35 Figure 17. Codec (U100) Scope Photo, Mute Condition ................................................................. 36 Figure 18. Microcontroller (U202) Scope Photo, Power Up ............................................................37 Figure 19. SPDIF Signal at U100 pin 42 .........................................................................................38 Figure 20. Microcontroller 8 MHz clock at U202 pin 39 ...................................................................38 Figure 21. Codec 11.2896 MHz Clock ............................................................................................39 Figure 22. 40 MHz DSP clock .........................................................................................................39 Figure 23. 3.3V Switching Power Supply Signals............................................................................40 Figure 24. Power Up Condition at U202 Pin 25 ...............................................................................40 Figure 25. Transmit Frame Sync .....................................................................................................41 Figure 26. Serial Data Clock ...........................................................................................................41 Figure 27. Audio Data .....................................................................................................................41

Click here to return to the main table of contents

22

Normal System Operation Description
Basic System Operation The Lifestyle® Series II system uses digital signal processing to bring even greater realism and impact to both movies and music recordings. Built-in Dolby Digital (AC-3) decoding delivers up to 5.1 discrete audio channels (i.e., five for the independent Satellite Speakers and one for rich bass from the Acoustimass® module) from DVD, digital TV, next-generation cable boxes, and satellite receivers. With analog formats, as well as for two-channel PCM and Dolby Digital bitstreams, Videostage® decoding directs stereo information to the surround channels, so the sound of stereo broadcasts and rented or recorded tapes can approach that of your DVD discs. In addition, Videostage decoding processes a one-channel program and directs five-channel sound to five independent speakers. Dialogue remains locked on-screen, while music and ambient effects fill the room to increase the listening enjoyment. The Lifestyle® Series II systems offers the option of listening in 5, 3 or 2-speaker mode. The system turns on in Surround (5-speaker) mode. For most video material (mono, stereo, or surround), listening in 5 or 3-speaker mode helps anchor the dialogue to the picture while providing a fuller sound. Enhanced Mode for Movie Soundtracks (Film EQ) Pressing the VIDEO 1, VIDEO 2, or AUX turns the system on in enhanced mode, with bass and treble settings specially designed for proper playback of movie soundtracks. Press the same button (VIDEO 1, VIDEO 2, or AUX) again to alternate between enhanced mode for movies and standard mode for other listening. Pressing TAPE turns the system on in standard mode. Press TAPE again to alternate between enhanced mode for movies and standard mode for other listening. Note: Enhanced mode provides more bass and treble, as is specified for proper playback of movie sound. Dynamic Range Compression Dynamic Range compression automatically adjusts the volume to allow you to hear soft sounds (particularly dialogue) and to prevent you from being overwhelmed by a loud special effect (i.e., an explosion). This feature is engaged when you turn on the system, but you may turn it on (one chime) or off (two chimes) (see explanation table on the next page) using the STEREO twospeaker button. Simulated Surround for Mono Movie Material Bose® Videostage decoding can process a one-channel program into five-speaker sound directing the signals so that dialogue remains locked on-screen, while music and ambient effects fill the room. You experience a surround sensation, providing extra enjoyment when you watch older (i.e., pre-stereo) movies. This feature can be used for mono TV, FM, and AM programs. Press the SURROUND (5-speaker) button to turn it on (one chime) or off (two chimes). This feature is automatically engaged when a Dolby Digital bitstream indicates that it contains a mono program.

23

Connection of Bass Module Using a CD-5/CD-20 Music Center
Test Setup Procedures Connect the input cable, part number, (253346 for the CD-20) or (253347 for the CD-5) to the music center and the bass module. Connect the power supply to the music center and the line cord to the bass module. Connect a satellite speaker to one of the output RCA connectors on the bass module. Apply a 100 mVrms, 250 Hz signal to the left and right AUX input on the music center. Turn the music center on and adjust the volume to maximum using the either the remote control or the buttons on the music center's control panel. The remote control would be the best option. Turn the system on by selecting the Aux button on the remote, and listen for audio from the bass box as well as the satellite speaker. If you hear audio using the remote control and a satellite speaker, check the outputs for left, right and center channel. Follow the instructions (from the owners manual) listed below for proper system function. If no audio output, go to the DSP troubleshooting section. Enhanced Mode Table

Source Video 1, Video 2, or Aux Tape CD and AM/FM

Default Mode Enhanced mode Standard mode Standard mode

Change Mode Select the same source for standard mode Select the same source for enhanced mode Cannot change mode in these sources

Dynamic Range Compression Table

Source Video 1, Video 2, or Aux

Dynamic Range Compression On by default

Change Dynamic Range Press and hold the STEREO (2speaker) button until two chimes are heard Press and hold the STEREO (2speaker) button until one chime is heard

CD, AM/FM, or Tape

Off by default

Simulated Surround (mono into 5 speakers)

Audio Source Mono Dolby Digital

Simulated Surround On by default

Any other audio source

Off by default

Change Simulated Surround Press and hold the SURROUND (5-speaker) button until two chimes are heard (OFF) Press and hold the SURROUND (5-speaker) button until one chime is heard (ON)

Reset Factory Speaker Level Settings

Selection Center Speaker Level Surround Speaker Level

Reset Factory Settings Press STEREO and CENTER (3-speaker) button until you hear a 3 note chime Press SURROUND (5-speaker) button until you hear a 3 note chime
24

Bass Box Troubleshooting Procedures
1. Check for Voltage at the Transformer 1.1 With the bass module completely assembled and the cover off, check for voltage at the transformer secondary. If there is voltage at the transformer secondary, skip to procedure 3. If there is no voltage on the transformer secondary, continue on to step 1.2. 1.2 Check for AC mains voltage, 120 or 240 VAC at the transformer primary. If there is voltage at the transformer primary, check the thermal fuse in the transformer primary and replace the transformer if it is open. If there is no voltage at the transformer primary, proceed as follows. 1.2.1 Check the fuse located on the PCB. 1.2.2 Ensure that the 18 conductor ribbon cable is fully seated. 1.2.3 With the line cord connected, connect the 10V turn-on signal to the 3.5 mm mono plug located on the test cable. Check the voltage at U300 pin 1. If it is ~1.25 VDC, U300 should be on, turning triac D302 on. Go to procedure 3. If it is ~0.8 VDC, the opto-coupler U300 is crowbarred off keeping triac D302 off, which connects 120 VAC to the transformer primary. Disconnect power to the bass module and go to procedure 2. 2. U300 Crowbarred Off, Triac D302 Off Note: Refer to Figure 50. Protection Circuit Simplified Schematic Diagram in the Appendix for an overview of the protection circuit. 2.1 If the bass module crowbars off (shuts off) immediately (<50 msec), check the "protect" signal at J8 pin 6. If the voltage on J8 pin 6 is greater than approximately +0.7 VDC, it will turn on Q202 and If the voltage is less than approximately -0.7V, it will turn on Q203. Turning on either Q202 or Q203 causes Q202 and Q203 to latch and this will activate the crowbar. If there is a fault condition at J8 pin 6, check the ±12 VDC, ±17 VDC and ±34 VDC power supplies. If the ±12 VDC power supply is not working and the ±34 VDC power supply is working, check resistive fuses R714 and R713 located on the amplifier PCB. A failed component could be causing one or more of these supplies to sag, causing the unit to crowbar off. If the DC power supplies are working, continue onto step 2.2. 2.2 DC offset at the output of the bass amplifier J703 pin 2 (+) and pin 1 (-) will produce a fault condition "protect" voltage (greater than approximately ±0.7 VDC) at J8 pin 6. Check the components in the bass amplifier with an Ohmmeter. 2.3 If the bass module crowbars off after approximately 3 seconds there could be DC offset on one or more satellite outputs. The satellite outputs are summed through the "speaker output DC offset" circuit (SD251571, grid location A7). The output of this circuit, P66, is sent to the microcontroller U202 pin 25. In normal operation, the voltage at U202 pin 25 should be 2.5 VDC. If the voltage strays more than 1 VDC from the normal 2.5 VDC, microcontroller U202 pulls pin 39 (P22) to ground (normally high impedance) pulling R308 to ground latching the circuit consisting of Q302 and Q303 (SD251571, grid location B4). This latch circuit, when latched, will shut off the opto-isolator U300, which will shut off the triac D302 disconnecting AC from the primary of the transformer. Note: U202 pin 26 is connected to U202 pin 39. The head unit does not send an "ON" command to the bass module. The uC knows when the power has just come up by watching the status of the 10V turn-on voltage via pin 26, which is connected to the same circuit mentioned above that the uC uses to shut down the triac. 25

Bass Box Troubleshooting Procedures
Note: Refer to Figure 15. DSP PCB Test Point Locations Layout Diagram, Solder Side on page 34 for the following procedures. 3. Microprocessor Circuit Check 3.1 The serial data output leaves the DSP PCB at J5 pin 11 (U202 pin 43, TTY OUT) and the boot prompt can be checked here at power-up with an oscilloscope. The first thing the uC is supposed to do when it comes out of reset is to print the following to the "debug" output J5 pin 11. ** %0001#01 This is visible as two bursts of activity. One immediately following the rising edge of the RESET line (**) and one about 50 msec later (%0001#01). After printing the boot prompt, the uC will only print error codes. Thus, a lack of activity on this signal after the initial two bursts is expected. Short bursts of activity is likely to be the uC printing out an error code. Refer to Figure 12.

Upper trace: RESET (active low) pulse U202 pin 14 or U200 pin 2 Middle trace: +5V supply Lower trace: Serial data from uC, J5 pin 11 Figure 12. Scope Photo of Boot Prompt at J5 Pin 11 3.2 If there is no boot prompt at U202 pin 43, then check for the following; +5 VDC at U202 pin 40 and U202 pin 18, 8 MHz clock on both sides of X600, reset pulse at power-up at U202 pin 14. If the +5 VDC, 8 MHz clock and reset pulse are okay and there is no boot prompt, then the Uc has failed. Replace the Uc U202.

26

Bass Box Troubleshooting Procedures
4. No Audio at Speaker Outputs 4.1 If there is no audio from the speaker outputs when an analog signal is applied to the input of the bass module, follow the audio signal path through the system. Refer to the following table. If there is audio from the speaker outputs when an analog signal is used but not when a SPDIF (Sony/Philips Digital Interface Format) signal is used, go to procedure 5.

Verify Signal at input connector Digital data from codec

Digital data from DSP to codec Codec output

At Location J5 pin 9 (L) and pin 1 (R) U100 pin 38 (sclk) U100 pin 37 (frame_sync) U100 pin 36 (data from codec) U100 pin 34 U100 pin 21 (right surround) U100 pin 22 (bass) U100 pin 23 (center) U100 pin 24 (left surround) U100 pin 25 (left) U100 pin 26 (right) U103 pin 1 (left) U103 pin 7 (right) U103 pin 8 (center) U103 pin 14 (left surround) U104 pin 1 (right surround) U104 pin 7 (bass) J8 pin 9 (left) J8 pin 7 (right) J8 pin 10 (center) J8 pin 12 (left surround) J8 pin 13 (right surround) J8 pin 11 (bass) J8 pin 17 (bass, left, right) J8 pin 16 (center) J8 pin 15 (left surround, right surround)

Note DIN input connector For pin 38 see Fig 34 For pins 37 and 36, see Fig 33 See Figure 33 High frequency noise, 2.3 Vdc bias

Buffers output

Gain of 6, no DC bias, less high frequency noise

Output at connector

Analog audio exits the DSP PCB at this point to enter the amplifier PCB

Amplifier mutes okay

0V = muted 5V = un-muted

5. No Audio Output when using a SPDIF Input (Figure 54, Digital Signal Path from Input Jack to CODEC Simplified Schematic Diagram) 5.1 Apply a SPDIF signal to the bass module SPDIF input and adjust the volume on the head-unit to maximum. 5.2 Check SPDIF signal path;

J5 pin 4 U100 pin 42 (if codec is in digital mode there should be 2.3 VDC on U100 pin 42).
5.3 Verify the DC voltage on the PLL line is clean; indicates that the PLL has locked onto the SPDIF signal. U100 pin 17.

27

Bass Box Troubleshooting Procedures
5.4 Capture the PLL tuning voltage as it goes from 0V (analog mode) to about 2V (digital mode). Voltage should slew and settle within about 5 msec. Any AC on the tuning line after the initial 10 msec, indicates a stability problem with the PLL circuit. 5.5 Verify that there is no error bit output from the codec. U100 pin 30 should be 0V. 5.6 Verify that the uC can see the SPDIF input. Check the voltage at the collector of Q201 and U200 pin 23. The voltage should be < 1 VDC, if there is an SPDIF present and > 4VDC if there is no SPDIF. 5.7 If the problem can't be located, go to procedure 6. 6. Quick Check/Possible Problems With DSP PCB 6.1 Because the DSP IC's legs are very fine, there is a chance for shorts or opens. Probing them can result in shorting them. Boot data can be garbled due to a short or open on the DSP IC pins. 6.2 The 40 MHz oscillator, CR400, might not be working. 6.3 There might be a broken "via" in the PCB. This is a hole in the PCB that connects traces on the top side of the PCB to traces on the bottom side of the PCB. This type of problem can be difficult to isolate. 6.4 If the problem has not been isolated, go to procedure 7. 7. Miscellaneous DSP PCB Troubleshooting Tips 7.1 +17V, ±12V Power Supplies The PCB draws power from three different supplies: 7.1.1 +17V unregulated, at about 250 mA when everything is running normally. The +17V supplies the unregulated voltages for the two voltage regulators on this PCB: the +5V linear regulator U1, and the 3.3V switching regulator U500. The +17V is brought onto the PCB from J8 pin 3. Note that the +17V unregulated supply can vary from about +17V to as low as +10V, depending on conditions. On the bench, the value may be more typically +15V or so. Whatever the exact voltage, in this document it will be referred to as the "+17V" supply. 7.1.2 ±12V, at about 40 mA or so. The ± 12V supplies are for the op-amps U103 -- U105. +12V is brought onto the PCB from J8 pin 1, and -12V is supplied from J8 pin 5. 7.2 +5V Supply Check the +5V supply first, since the +5V powers the microcontroller, and without it, nothing else works. Check the following points: 7.2.1 At the input side to the +5V regulator U1. This is a typical