Bose 402 Series User manual

Service Manual
©2009 Bose Corporation
402®Series II Loudspeaker
Reference Number 260431-SM Rev. 02
Electronic copy only

2
SPECIFICATIONS
WARRANTY
5 year limited warranty
PROPRIETARY INFORMATION
THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION
OF BOSE®CORPORATION WHICH IS BEING FURNISHED
ONLY FOR THE PURPOSE OF SERVICING THE IDENTIFIED
BOSE PRODUCT BY AN AUTHORIZED BOSE SERVICE CEN-
TER OR OWNER OF THE BOSE PRODUCT, AND SHALL NOT
BE REPRODUCED OR USED FOR ANY OTHER PURPOSE.
Specifications ....................................................................................................................................1
Disassembly/Assembly Procedures ........................................................................................... 2-3
Figure 1. Schematic Diagram ..............................................................................................................3
Test Procedures ................................................................................................................................4
Main Part List.....................................................................................................................................5
Figure 2. Exploded View ......................................................................................................................5
Crossover PCB Part List ..................................................................................................................6
Figure 3. Crossover PCB Layout ........................................................................................................6
Packaging Part List ...........................................................................................................................6
Figure 4. Packaging View ....................................................................................................................6
External dimensions:
Single speaker: 23.3" H x 8.2" W x 7.8" D (59.2 x 20.8 x 19.8)cm
Packed system: 27.0" H x 12.0" W x 11.0" D (68.6 x 30.5 x 27.9)cm
Weight:
Single speaker: 17.5 lbs (7.94 kg)
Packed system: 21.3 lbs (9.66 kg)
Transducer: Four 4.5" environmental drivers per enclosure
Internal cabinet volume: 1067.9 cu. In. (17.5 liters)
Port:
Type: Two rectangular ports located at the top and bottom.
Total port area: 8.84 sq. in. (57 sq. cm)
Port length: 3.23" (8.2cm)
Resonance frequency: 90 Hz
Impedance: 8 ± 2 Ohm
Power handling: 120W continuous per IEC-268-5
Sensitivity: 90 dB SPL, 1W, 1m
CONTENTS

3
Figure 1. Exploded View
MAIN PART LIST
1
2
34
56
2
7
8
9
10
11
12
13
14
15
16
17
12x
4x
2x
2x
2x 2x
2x
2x
12x
4x
4x
Item
Number Description Part Number Qty Note
1 GRILLE, BLACK
GRILLE, ARCTIC WHITE
GRILLE, PRO GRAY
252380-001
252380-002
252380-004
1
2 SCREW, TAPP, 8-15, HEXW, SLOT 290290-12 14
3 DRIVER ASSEMBLY, 4.5" 291020-001 4 1
4 GASKET, DRIVER, 4.5" 128407 4
5 FOAM, ACOUSTIC, 19.75"x7"x1 120357 1
6 CLIP, TINNERMAN 187943 2
7 CROSSOVER ASSEMBLY 291042-001 1
8 CONN, SPEAKON, PANEL MOUNT 258213-002 2
9 SCREW, THUMB, M8x1.25x25mm 137050 2
10 CONN, FUSE CLIP, 1 POS, FEMALE 121112 2
11 SCREW, TAPP, 6-20x.5, PAN, XR 290296-08 2
12 TAPE, FOAM 257555 1
13 NUT, J-TYPE, 8-32 109481 12
14 INSERT, KNURLED 290293-01 4
15 DEFLECTOR 126973-1 1
16 SCREW, TAPP, 6-13x.625, PAN 290294-10 4
17 NAME PLATE, LOGO, BLACK
NAME PLATE, LOGO, WHITE 254458-001 254458-002 1
Note: When ordering a driver, also order a driver gasket.

4
PACKAGING PART LIST
Figure 3 Packaging View
Item
Number
Description Part
Number
Qty
1 LAMP, AXIAL LEAD 114462 2
2 20uF, CAP, FILM, 75V, 10% 119026 1
CROSSOVER PCB PART LIST
Figure 2. Crossover PCB Layout
21
x2
1
2
3
4
2
3
5
6
Item
Number
Description
Part Number
Qty
Note
1 PACKING, FOAM, BOTTOM, EPS 258908 1
2 PACKING, FOAM, P/U, RIGHT 258927 2
3 PACKING, FOAM, P/U, LEFT 258928 2
4 MANUAL, OWNERS 256597 1
5 BAG, POLY, 13.5x35x9.5x1 MIL 114522 1
6 CARTON, RSC, 402 II 256591 1

5
3.4 Cut the wires as close as possible to the
driver’s wire terminal.
4. Driver Replacement
4.1 Referring to the schematic below, attach
the wires to the driver (1).
4.2 Line up the driver (1) to the cabinet and
secure it with three screws (7).
4.3 Line up the deflector (8) with the cabinet
and secure it with four screws (12).
5. Crossover Removal
5.1 Remove the three screws (7) securing the
top driver (1) to the cabinet. Lift out the driver.
5.2 Remove the two screws (7) securing the
crossover PCB to the cabinet.
5.3 Pull the crossover PCB through the driver
opening in the cabinet.
Deflector
Crossover PCB
DISASSEMBLY/ASSEMBLY PROCEDURES
45
0
Note: Numbers in parenthesis correspond to
call-outs in figure 1.
1. Grille Removal
1.1 Rotate the Bose® logo (9) 450to release
the grille (6).
1.2 Grasp the edge of the grill and pull it off.
2. Grille Replacement
2.1 Rotate the Bose logo (9) 450so the
locking tabs on the logo line up with the slot
on the deflector (8). Press the grille into place.
2.2 Rotate the Bose logo horizontally, locking
the grille into place.
3. Driver Removal
3.1 Perform procedure 1.
3.2 Remove the four screws (12) securing the
deflector (8) to the cabinet. Lift off the deflector.
3.3 Remove the three screws (7) securing the
driver (1) to the cabinet. Lift out the driver.

6
7.3 Pull out the Speakon connector and
remove the wires.
8. Speakon Connector Replacement
8.1 Referring to figure 1, attach the wires to
the Speakon connector (4).
8.2 Align the Speakon connector in the
cabinet.
8.3 Reshape the tinnerman clip (5) or use a
new one. Place an appropriate size wood
block between the Speakon connector (rear
of speaker) and a hard surface. Using a flat-
blade screwdriver (or similar tool) and a
hammer, secure the tinnerman clip into place.
Make sure the Speakon connector is securely
fastened.
6. Crossover Replacement
6.1 Replace the two screws (7) securing the
crossover PCB (3) to the cabinet.
6.2 Perform procedure 4 and 2.
7. Speakon Connector Removal
7.1 Perform procedure 3.1-3.3 to remove the
two center drivers.
7.2 Using a flat-blade screwdriver, pry out the
tinnerman clip (5) securing the Speakon
connector (4) to the cabinet.
DISASSEMBLY/ASSEMBLY PROCEDURES
Speakon
Connector
Tinnerman Clip
Figure 4. Schematic Diagram

7
1. Phase Test
1.1 Observing polarity, apply 9 VDC to the
input connector. Refer to the figure below.
1.2 All driver cones should move outward.
Referring to figure 4, rewire any driver that
moves inward.
2. Crossover Test
2.1 Connect a 0.5 Ohm resistor and amplifier
to the speaker input connector as shown in
the diagram below.
2.2 Apply a 2 Vrms, 8 kHz signal to the
speaker input connector.
2.3 Measure the voltage across the 0.5 Ohm
resistor. It should be 68-90 mVrms. If the
voltage is out of range, check the crossover
components and wiring.
3. Rub and Tick Test
3.1 Apply a 9 Vrms, 10 Hz signal to the
speaker input connector.
3.2 No extraneous noises such as rubbing,
scraping or ticking should be heard.
Note: To distinguish between normal suspen-
sion noise and rubs or ticks, slightly displace
the cone of the driver with your fingers. If the
Amplifier
+
-
0.5 Ohm
+
-
Speaker
Volt meter
-+
Speaker output
TEST PROCEDURES
noise can be made to go away or get worse, it
is a rub or tick and the driver should be
replaced. If the noise stays the same, it is
normal suspension noise and the driver is
fine. Suspension noises will not be heard with
program material.
4. Air Leak Test
4.1 Apply a 15 Vrms, 65 Hz signal to the
speaker input connector.
4.2 Listen for air leaks around the drivers and
cabinet seam. Reposition or replace any
gasket that is found to leak. Repairs made to
the cabinet seam should not be visible from
the exterior of the speaker.
5. Sweep Test
5.1 Apply a 9 Vrms, 10 Hz signal to the
speaker input connector.
5.2 Sweep the signal generator from 10 Hz to
500 Hz.
5.3 Apply a 500 Hz, 2 Vrms signal to the
speaker input connector.
5.4 Sweep the signal generator from 500 Hz
to 5 kHz.
5.5 Listen for buzzes, rattles or other noises.
Redress any wire that buzzes; replace any
driver that is found to be defective.
Note: A whooshing noise from the port at its
resonance frequency of approximately 90 Hz
is acceptable.
1+
2+
1-
2-
Positive input
Negative input

8
SERVICE MANUAL REVISION HISTORY
Date Revision
Level
Description of Change Change Driven By Pages
Affected
02/01 00 Document release revision 00
Service manual release All
02/06 01 Added RoHS part numbers This product is now built
with RoHS compliant parts. 3
1/07 No change Corrected part number, Driver
Assembly, 4.5” Correct part number is 254451 3
5/09 02 - New part numbers for
speaker parts and packaging
- Layout changed to reflect
current manuals
Part changes
Service manual layout
change
3, 4
All
1

Specifications and Features Subject to Change Without Notice
Bose Corporation
The Mountain
Framingham Massachusetts USA 01701
P/N 260431-SM Rev. 02 05/2009 (P) For Technical Assistance or Part Orders, Call 1-800-233-4408
http://serviceops.bose.com