Tuesday, February 09, 2016

BOSE L1 MODEL 1 SYSTEM - Disassembling procedure - step by step disassembling procedure – L1 Model I Power Stand removal - Line Array Disassembly Procedures - Bass Module Disassembly Procedures - Audio system repair and service

Category: Audio System Repair and Service 

Contents of this article 

  • Stand disassembling 
  • Line Array disassembling 
  • Bass module dissembling 




BOSE L1 MODEL 1 SYSTEM

L1 Model I Power Stand Disassembly Procedures
1. Lower Housing Removal
1.1 Place the power stand on a soft surface so that the line array opening faces down.
1.2 Using a Phillips-head screwdriver, remove the 19 screws that secure the lower housing to the upper housing. Lift off the lower housing.

2. Amplifier Housing Removal
2.1 Perform procedure 1.
2.2 Make a note of the wiring, and disconnect the wiring harnesses and connectors that run to the amplifier housing. The amplifier housing is the large metal box with the four fans.
2.3 Using a Phillips-head screwdriver, remove the four screws that secure the power stand base plate to the bottom of the line array cavity. Lift it off of the cavity. Be careful not to damage any wires.
2.4 Once all of the wiring is disconnected, use a Phillips-head screwdriver to remove the 16 screws that secure the amplifier housing to the power stand upper housing. Carefully lift the amplifier housing out of the power stand upper housing.

3. Line Array Cavity Removal
3.1 Perform procedure 2.
3.2 Using a Phillips-head screwdriver, remove the three screws that secure the line array cavity to the upper housing. Lift the line array cavity off of the upper housing. The power stand foot pedal will disengage from the shaft.

4. Amplifier PCB Removal
4.1 Perform procedure 2.
4.2 Make a note of the wiring and disconnect all of the wiring harnesses that connect the power supply box to the DSP PCB and to the microprocessor PCB.
4.3 Using a Phillips-head screwdriver, remove the 24 screws that secure the power supply box top cover in place. Lift off the top cover.
4.4 Once you have the top cover off, make a note of the wiring configuration and unplug the wiring harnesses that connect to the amplifier PCB.
4.5 Using a Phillips-head screwdriver, remove the 6 screws that secure the amplifier PCB in place. Lift the amplifier PCB out of the chassis.

5. +/-27VDC SMPS Removal
5.1 Perform procedure 2.
5.2 Make a note of the wiring and disconnect all of the wiring harnesses that connect the power supply box to the DSP PCB and to the microprocessor PCB.
5.3 Using a Phillips-head screwdriver, remove the 24 screws that secure the power supply box top cover in place. Lift off the top cover.
5.4 Once you have the top cover off, make a note of the wiring configuration and unplug the wiring harnesses that connect to the switching DC power supply PCB you wish to remove.
5.5 Using a Phillips-head screwdriver, remove the 4 screws that secure power supply PCB in place. Lift the power supply PCB out of the chassis.

6. Auxiliary Power Supply Removal
6.1 Perform procedure 2.
6.2 Make a note of the wiring and disconnect all of the wiring harnesses that connect the power supply box to the DSP PCB and to the microprocessor PCB.
6.3 Using a Phillips-head screwdriver, remove the 24 screws that secure the power supply box top cover in place. Lift off the top cover.
6.4 Once you have the top cover off, make a note of the wiring configuration and unplug the wiring harnesses that connect to the switching DC power supply PCB you wish to remove.
6.5 Using a Phillips-head screwdriver, remove the 4 screws that secure the power supply PCB in place. Lift the power supply PCB out of the chassis.

7. EMI (FCC) Filter PCB Removal
7.1 Perform procedure 2.
7.2 Make a note of the wiring and disconnect all of the wiring harnesses that connect the power supply box to the DSP PCB and to the microprocessor PCB.
7.3 Using a Phillips-head screwdriver, remove the 24 screws that secure the power supply box top cover in place. Lift off the top cover.
7.4 Once you have the top cover off, make a note of the wiring configuration and unplug the wiring harnesses that connect to the EMI Filter PCB.
7.5 Using a Phillips-head screwdriver, remove the 4 screws that secure the EMI Filter PCB in place. Lift the EMI Filter PCB out of the chassis.

8. Chassis Fan Removal
8.1 Perform procedure 2.
8.2 Using a Phillips-head screwdriver, remove the 24 screws that secure the power supply box top cover in place. Lift off the top cover.
8.3 Using a Phillips-head screwdriver, remove the 4 screws that secure the fan to the chassis.
8.4 Follow the wire harness for the fan you are removing to the auxiliary power supply PCB and unplug it. Lift the fan out of the chassis.
Re-assembly note: When installing the new fan, be sure to match the orientation of the fan next to it so that it will move air in the proper direction when in use.


9. Microprocessor PCB Removal
9.1 Perform procedure 1.
9.2 Make a note of the wiring configuration and unplug the six wire harnesses from the connectors on the board.
9.3 Lift the microprocessor PCB off of the connectors that engage it on the bottom of the board and the pins that connect to the preset switches.
Re-assembly note: When re-installing this PCB, be sure that all of the pins from the preset switches are straight and properly engage the connectors on the bottom of the microprocessor PCB.

10. DSP PCB Removal
10.1 Perform procedure 1.
10.2 Make a note of the wiring configuration and unplug the six wire harnesses from the connectors on the board.
10.3 Using a pair of needle-nose pliers, compress the bottoms of the plastic standoff posts used to attach the DSP PCB to the Input/Output PCB. Lift the DSP PCB off of the I/O PCB.

11. Input/Output PCB Removal

11.1 Perform procedures 9 and 10.
11.2 On the front panel of the power stand, remove the four knobs for the mic trim and level controls.
11.3 Using a nut driver, remove the nuts and washers for the 1/4 inch phono jacks.
11.4 Using a Phillips-head screwdriver, remove the screws that secure the XLR, Data in/out and Neutrik connectors to the front panel.
11.5 Lift the I/O PCB off of the input panel
Line Array Disassembly Procedures
Note: The line arrays are divided into a lower line array, which plugs directly into the power stand, and an upper line array, which uses a bayonet arrangement to align the upper array to the lower array for connection. All electrical connections are automatically made when the arrays are mounted into the power stand and the upper array is mounted to the lower array.
Note: Refer to Figure 8 for the following procedures.
1. Grille Removal
1.1 Using a Phillips-head screwdriver, remove the six screws that secure the end cap to the line array enclosure. Lift off the end cap. Unplug the molex connector from the speaker harness.
1.2 Grasp the edge of the grille and gently lift it away from the enclosure.
2. Nameplate Removal
2.1 Perform procedure 1.
2.2 On the back of the grille, unbend the legs of the logo. Lift off the nameplate.
3. Driver Removal
3.1 Perform procedure 1.
3.2 Using a Phillips-head screwdriver, remove the four screws that secure the driver to the enclosure.
3.3 Lift the driver out of the enclosure. Note the wiring configuration and cut the wires as close to the driver terminals as possible.
4. Upper Line Array Top End Cap Removal
4.1 Using a Phillips-head screwdriver, remove the seven screws that secure the end cap to the line array enclosure. Lift off the end cap.
Re-assembly note: Make sure that the end cap gasket is properly aligned to achieve an airtight seal.
5. Upper Line Array Bottom End Cap Removal
5.1 Using a Phillips-head screwdriver, remove the seven screws that secure the end cap to the line array enclosure. Lift the end cap away from the enclosure. Unplug the molex connector from the speaker harness.
Re-assembly note: Make sure that the end cap gasket is properly aligned to achieve an airtight seal.
6. Lower Line Array Top End Cap Removal
6.1 Using a Phillips-head screwdriver, remove the six screws that secure the end cap to the line array enclosure. Lift off the end cap. Unplug the molex connector from the speaker harness.
Re-assembly note: Make sure that the end cap gasket is properly aligned to achieve an airtight seal.
7. Lower Line Array Bottom End Cap Removal
7.1 Using a Phillips-head screwdriver, remove the seven screws that secure the end cap to the line array enclosure. Lift the end cap away from the enclosure. Unplug the molex connector from the speaker harness.
Re-assembly note: Make sure that the end cap gasket is properly aligned to achieve an airtight seal.
8. Front Cap Removal
8.1 Using a Phillips-head screwdriver, remove the four screws that secure the front cap to the bottom front of the line array enclosure. Lift the end cap away from the enclosure
Bass Module Disassembly Procedures
1. Grille Removal
1.1 Using an allen wrench, remove the four screws that secure the grille to the upper and lower speaker end caps.
1.2 Lift off the grille.
2. Nameplate Removal
2.1 Perform procedure 1.
2.2 On the back of the grille, remove the retaining nut and spring from the post of the nameplate. Lift the nameplate off of the grille.
3. Driver Removal
3.1 Perform procedure 1.
3.2 Using a Phillips-head screwdriver, remove the four screws that secure the driver to the bass module enclosure.
3.3 Lift the driver out of the enclosure. Note the wiring configuration and cut the wires as close to the driver terminals as possible.
Re-assembly notes:
- When soldering the speaker harness wires to the new driver, be sure to observe polarity of the driver harness wires.
- Be sure to properly align the gasket behind the new driver to ensure an airtight fit.
4. Input Panel Removal
4.1 Using a Phillips-head screwdriver, remove the four screws that secure the input panel to the bass module enclosure.
4.2 Lift the input panel away from the bass module enclosure.
4.3 Make a note of the wiring configuration and un-solder the speaker harness wires from the input panel.