Bose 321 270000 sm rev2 pages38 49
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39 DISASSEMBLY PROCEDURES 3.5 On the rear of the console base (21), unclip the four tabs that secure the I/O panel (19) to the base. Pull away and down on the top of the I/O panel until it unclips from the base. It should come off completely. 3.6 Carefully lift the front edge of the main PCB (20) out of the base. Slide the main PCB forward slightly until it clears the jacks on the back of the board. Lift the main PCB out of the base. Re-assembly notes: Be sure to install a thermal barrier, Bose part number 267574-001 into the console chassis before re-installing the main PCB. On the main PCB, check to make sure that the large thermal pad (16) is in place on top of the DVD decoder IC (U3000) and the small thermal pad (17) is in place on top of the CODEC IC (U4000). Check that the eight small EMI shield conductive strips (15,18) are in place in the groove around the bottom of the casting (14). On the heatsink (9), use a straight-edge razor blade to scrape off any thermal phase change pad (11) material. Take care to not scratch the coating on the heatsink. Clean off any residue with alcohol. On the main PCB, clean any thermal phase change pad residue off of the output IC. Apply a small amount of thermal compound to the back of the output IC. 4. LCD Display PCB Removal 4.1 Perform procedure 2. 4.2 On the main PCB (20), unplug the ribbon cable at jack J6500. Peel off the foil ground strap (24) located directly under the ribbon cable. You will need to re-install this later. 4.3 Using a small flat-tip screwdriver, press in the tabs that secure the bezel sub assem- bly (26) to the console base (21). There are two located at the top of the base behind the front panel near the ribbon cable and the heatsink (9). There are two more inside the opening for the DVD drawer.Release the four tabs on the bottom of the base directly behind the bezel sub assembly. Take care not to drop the LCD display PCB. 4.4 Place the bezel sub assembly face down on a soft surface. Lift the LCD display PCB out of the bezel sub assembly. Using a small flat-tip screwdriver, flip up the edge of the ZIF connector at J2. Unplug the ribbon cable. Take care to not plug and unplug this cable too many times. It has a carbon coat- ing that wears off after just a few removals and insertions, ruining the cable. Bass Module Procedures Refer to Figure 2 for the following proce- dures. 1. Rear Enclosure Removal 1.1 Place the bass module on its side. Using a Phillips-head screwdriver, remove the four screws (9) that secure the rear enclosure (8) to the bass module. 1.2 Slide the rear enclosure off of the bass module. 2. Power Transformer Removal 2.1 Perform procedure 1. 2.2 On the bass module PCB/heatsink assembly, unplug the cables at J3 and J5 that run to the power transformer. Unplug the woofer harness cable at J7. 2.3 Using an 8/32" nut driver, remove the four nuts (6) that secure the power trans- former (7) to the bass module enclosure. 2.4 Lift the power transformer off of the mounting studs (5) and out of the enclosure.
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40 DISASSEMBLY PROCEDURES 3. Bass Module PCB/Heatsink Assembly Removal 3.1 Perform procedure 1. 3.2 On the bass module PCB/heatsink assembly (10), unplug the cables at J3 and J5. Unplug the woofer harness cable at J7. 3.3 Remove the four screws (11) that secure the bass module PCB/heatsink assembly to the enclosure. Lift it out of the enclosure. 3 21 Satellite Array Procedures Note: The standard 321 (non-GS) satellite arrays are non-repairable. The only parts that can be replaced are the grille and the name- plate. 1. Grille Removal 1.1 Wrap some masking tape around the shaft of a flat-tip screwdriver approximately 1/2" back from the end. This is needed to protect the plastic enclosure of the array. 1.2 Place the satellite array on its back on a bench. Use your thumb to press down on the array grille at the center of the curve near the side. At the same time, use the screwdriver to pry the end of the grille off of the array enclosure. Repeat this at the other end of the grille. 2. Nameplate Removal 2.1 Perform satellite array procedure 1. 2.2 On the back of the grille (1), unbend the two metal legs that secure the nameplate (2) to the grille. Pull the nameplate away from the grille.3 21 GS Satellite Array Procedures Note: Refer to the figure below for the following procedures. 1. Grille Removal 1.1 Using a scribe or small flat blade screw- driver to grasp the edge of the grille (2). Gently pull the grille away from the enclo- sure. 2. Twiddler TM Removal 2.1 Perform procedure 1. 2.2 Using a Philips-head screwdriver, re- move the four screws (5) that secure the driver (1) you wish to remove. 2.3 Lift the driver out of the enclosure and remove the two faston connectors of the wiring harness. Re-assembly note: Be sure that the driver gasket is properly aligned behind the driver to ensure an airtight seal. 1 2 3 44x 58x1