Bose FreeSpace DXA 2120 User manual

©2010 Bose Corporation Reference Number 294962-SM Rev. 01
Service Manual
FreeSpace® DXA 2120
Digital Mixer/Amplifier
(US and non-US units)
Electronic Copy Only

2
CONTENTS
Safety Information.............................................................................................................................3
Warranty .............................................................................................................................................3
Product Description ..................................................................................................................... 4-7
Specifications................................................................................................................................ 8-9
Electrostatic Discharge Sensitive (ESDS) Device Handling.....................................................10
Part List Notes ................................................................................................................................10
Packaging Part List, FreeSpace®DXA 2120 Amplifier/Mixer (see Figure 1) .............................11
Figure 1. FreeSpace DXA2120 Packaging View ............................................................................11
Main Part List, FreeSpace DXA 2120 Amplifier/Mixer (see Figure 2).........................................12
Figure2. FreeSpaceDXA2120Amplifier/MixerExploded View ......................................................13
Electrical Part Lists .................................................................................................................. 14-52
Control PCBAssembly ............................................................................................................. 14-16
DC24 PCBAssembly ................................................................................................................. 17-18
Digital Signal Processor (DSP) PCB Assembly ..................................................................... 19-28
Input/Output PCBAssembly .................................................................................................... 29-35
Amplifier PCBAssembly ........................................................................................................... 36-40
PSU PCBAssembly................................................................................................................... 41-44
RCAInput PCBAssembly ......................................................................................................... 45-49
RS-232 PCBAssembly ....................................................................................................................50
Speaker PCB Assembly ............................................................................................................ 50-51
Volt PCBAssembly ..........................................................................................................................52
Figure 3. FreeSpace DXA2120Amplifier with Top Cover Removed ...............................................53
Disassembly Procedures ......................................................................................................... 54-61
Test Procedures ....................................................................................................................... 62-70
FreeSpace DXA-2120 Firmware Update Procedure.............................................................. 71-72
FreeSpace DXA-2120 Wiring Diagram ..........................................................................................74
Figure 4. DSP and MCU PCB Topside Etch Layout........................................................................75
Figure 5. DSP and MCU PCB Bottom Etch Layout ........................................................................75
Figure 6. Input/Output PCB Topside Etch Layout............................................................................76
Figure 7. Input/Output PCB Bottom Etch Layout ............................................................................76
Figure 8. Volt PCB Topside Etch Layout .........................................................................................77
Figure 9. Volt PCB Bottom Etch Layout ..........................................................................................77
Figure 10. Speaker PCB Topside Etch Layout ................................................................................77
Figure 11. Speaker PCB Bottom Etch Layout .................................................................................77
Figure 12. RS232 PCB Topside Etch Layout..................................................................................77
Figure 13. RS232 PCB Bottom Etch Layout...................................................................................77
Figure 14. PSU PCB Topside Etch Layout......................................................................................78
Figure 15. PSU PCB Bottom Etch Layout ......................................................................................78
Figure 16.Amplifier PCB Topside Etch Layout................................................................................79
Figure 17.Amplifier PCB Bottom Etch Layout ................................................................................79
Figure 18. DC24 PCB Topside Etch Layout....................................................................................79
Figure 19. DC24 PCB Bottom Etch Layout ....................................................................................79
Figure 20. Control and Display PCB Topside Etch Layout..............................................................80
Figure 21. Control and Display PCB Bottom Etch Layout...............................................................80
Figure 22. RCAInput andA/D PCB Topside Etch Layout................................................................81
Figure 23. RCAInput andA/D PCB Bottom Etch Layout ................................................................81
Integrated Circuit Diagrams .................................................................................................... 82-91
Troubleshooting .............................................................................................................................92
Service Manual Revision History .................................................................................................93

3
SAFETY INFORMATION
1. Parts that have special safety characteristics are identified by the symbol on schematics
or by special notes on the parts list. Use only replacement parts that have critical characteristics
recommended by the manufacturer.
2. Make leakage current or resistance measurements to determine that exposed parts are
acceptably insulated from the supply circuit before returning the unit to the customer.
Use the following checks to perform these measurements:
A. Leakage Current Hot Check-With the unit completely reassembled, plug the AC line cord
directly into a 120V AC outlet. (Do not use an isolation transformer during this test.) Use a
leakage current tester or a metering system that complies with American National Standards
Institute (ANSI) C101.1 "Leakage Current for Appliances" and Underwriters Laboratories (UL)
UL6500 / UL60065 / IEC 60065 paragraph 9.1.1. With the unit AC switch first in the ON position
and then in OFF position, measure from a known earth ground (metal waterpipe, conduit, etc.)
to all exposed metal parts of the unit (antennas, handle bracket, metal cabinet, screwheads,
metallic overlays, control shafts, etc.), especially any exposed metal parts that offer an electrical
return path to the chassis. Any current measured must not exceed 0.5 milliamp. Reverse the
unit power cord plug in the outlet and repeat test. ANY MEASUREMENTS NOT WITHIN THE
LIMITS SPECIFIED HEREIN INDICATE A POTENTIAL SHOCK HAZARD THAT MUST BE
ELIMINATED BEFORE RETURNING THE UNIT TO THE CUSTOMER.
B. Insulation Resistance Test Cold Check-(1) Unplug the power supply and connect a jumper
wire between the two prongs of the plug. (2) Turn on the power switch of the unit. (3) Measure
the resistance with an ohmmeter between the jumpered AC plug and each exposed metallic
cabinet part on the unit. When testing 3 wire products, the resistance measured to the product
enclosure should be between 2 and infinite MOhms. Also, the resistance measured to exposed
input/output connectors should be between 4 and infinite MOhms. When testing 2 wire prod-
ucts, the resistance measured to exposed input/output connectors should be between 4 and
infinite MOhms. If it is not within the limits specified, there is the possibility of a shock hazard,
and the unit must be repaired and rechecked before it is returned to the customer.
CAUTION: The Bose®FreeSpace® DXA 2120 Digital Mixer/Amplifier
contains no user-serviceable parts. To prevent warranty infractions,
refer servicing to warranty service stations or factory service.
PROPRIETARY INFORMATION
THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OF
BOSE CORPORATION WHICH IS BEING FURNISHED ONLY FOR
THE PURPOSE OF SERVICING THE IDENTIFIED BOSE PRODUCT
BYAN AUTHORIZED BOSE SERVICE CENTER OR OWNER OF
THE BOSE PRODUCT, AND SHALL NOT BE REPRODUCED OR
USED FOR ANY OTHER PURPOSE.
The Bose FreeSpace DXA 2120 Digital Mixer/Amplifier is covered by a limited 2-year transfer-
able limited warranty.
WARRANTY

4
Product Description
The Bose®FreeSpace®DXA 2120 Digital
Mixer/Amplifier integrates digital signal
processing with two 120-watt output
channels. Designed as a mixer/router for
business music applications, it features
an LCD panel and control buttons behind the front cover for ready access and easy configura-
tion.
The mixer/amplifier provides six inputs, including 4 Mic/Line inputs, 1 Page input, and 1 Direct
input. The Direct input can override all sources playing on the output channels. Each Mic/Line
input provides both RCA and Euroblock jacks. The Euroblock connectors will accept either a Mic
or Line level input. The RCAjacks accept Line level inputs only.
Two output channels are wired for 120 watts at 4 ohms each. For 70/100 volt applications, a
jumper is required for proper configuration. In 70/100V applications, the two outputs will operate
at 100 watts per channel. A third output is available for an auxiliary line out.
Additional features include:
•Signal Mixing: In Mixer Mode, simultaneously combines up to four inputs for any of the
three outputs.
•Signal Routing: In Dual Mono Select Mode, one or two inputs go to each of two outputs in
different zones and can be remotely selected. Or in Stereo Select Mode, two stereo sources
go to one output zone and can be remotely selected.
•Opti-voice®Paging: Provides a smooth transition between music and page signals.
•Dynamic Equalization: Maintains tonal balance at all listening levels.
•Room Equalization: Allows easy adjustment of tonal balance in each zone.
•Communications Port: Includes an RS-232 serial port in reserve for system updates.
•Back-up Power: Provides an input terminal for a +24V DC back-up power source.
Supplied with the product
Included Connectors:
•3-terminal input connectors (4) for wiring source equipment to 1 - 4 Line/Mic input Euroblock
jacks.
•4-terminal input connectors (2) for wiring to the single Page and single Direct input jacks.
•6-terminal input connector (1) for wiring to interface wall controls to the wall panel input jack.
•3-terminal output connector (1) for wiring to the AUX-out jack.
Included placement aids:
•Non-skid rubber feet (4) for stable placement on a solid, level surface.
•Rack ears (2) with mounting hardware for installation in a rack.
Mixer/Amplifier Accessories
•FreeSpace DXA volume control - A wall-mountable plate with volume control knob that fits
into a standard U.S. double-gang junction.box.
•FreeSpace DXA volume control with A/B select -A wall-mountable plate that fits into a
standard U.S. double-gang junction box. It features volume control and A/B select knobs for
remote source selection.
POW ER

5
System Controls
1 - LCD panel - Displays menu selection for
configuring and viewing system settings.
2 - Directional buttons - Navigate system
menus and setting options as shown on the
LCD.
3 - Select button - Confirms selections and
settings in the system menus.
4 - Power LED - Blue light indicates the
system is on. No light when it is off.
5 - Signal and Clip LEDs - Show signal
states for OUPUT 1, OUTPUT 2, PAGE and
DIRECT.
Signal Unlit = No signal
Clip Unlit = No clipping
Signal Green = Signal present
Clip Red = Clipping
6 - Gain knobs - Adjust gain for OUTPUT 1,
OUTPUT 2 and PAGE.
Hardware Description
7 - Bass and Treble knobs - Adjust tonal
balance for OUTPUT 1 and OUTPUT 2.
Control Compartment
8 - Enclosure Door - Conceals system
controls.
Input Controls
9 - SIGNAL and CLIP LEDs - Show signal
states for Inputs 1 - 4.
Signal Unlit = No signal
Clip Unlit = No clipping
Signal Green = Signal present
Clip Red = Clipping
10 - Gain knobs - Adjust gain for INPUT 1 -
INPUT 4.
Front panel with open compartment
Front panel with compartment closed
1
2
3
4
5
6
8
9
10
7
1Latch location – Provides access to system controls. 2Power status window – Reveals Power LED.
2
1

6
Hardware Description
Rear Panel
Audio source inputs
1 - INPUT 1 of 4 - Unbalanced RCA audio
input jack.
2 - MIC/LINE switch - To adjust for the type
if signal input. (Mic connections require
using Euroblock input jacks.)
3 - INPUT 2 of 4 - Balanced Euroblock audio
input jack.
4 - DIRECT INPUT - Balanced override input
jack.
5 - PAGE INPUT - Balanced audio input
jack.
Outputs
6 - AUX OUTPUT - Line-level signal output
for other amplified equipment.
7 - OUTPUT 1 of 2 - Speaker connections
for two powered outputs of 70V, 100V or 4
ohms.
Control Input
8 - REMOTE - Input jack for Volume control
and Volume control with A/B select wallplate
user interfaces.
Power
9 - BACKUP POWER - For connection to
backup power source.
10 - POWER ON/OFF - AC power switch
11 - FUSE - 120V T6.3A/250V L or 240V
T3.15A/250 L.
12 - AC mains line cord jack - AC line
voltage input.
13 - 120V/220-240V switch - Switches
between 120V and 220-240V AC input
voltage. This switch is not provided on 100V
AC input voltage models.
1 32458
7
910
12
13
14
11
6
Communication
14 - COM - RS-232 serial port for system
updates.
Wall Plates
The FreeSpace®DXA 2120 is designed to be
compatible with the following Bose user
interfaces:
•Bose Volume Control User Interface
(PC 041966)
•Bose Volume Control with A/B Select
User Interface (PC 041967)

7
System Setup
This section provides instructions on setting
the system for preferred operation. To make
these settings, the system must be con-
nected to power and the AC POWER switch
set to ON.
Note: When the system is unplugged, or if a
power loss occurs, these system settings
are retained in flash memory. However,
continuous system operation during a power
loss requires the use of an optional backup
power source.
System Setup Procedure
When first turned on, pressing any button
next to the LCD activates the display.
• If the system is locked, simultaneously
press the left and right arrow buttons and
hold for five seconds. Lockout Off appears.
• When the system is unlocked, you can
navigate to system setup options.
•Use the arrow and SELECT buttons to
move through the menus and change
settings for the equipment used and the
type of connections made in your instal-
lation.
• Notice the type of setting in each field:
- Level changes (designated by Lvl) are
made using the GAIN knobs only. These
levels appear in the menu field, but
cannot be changed in the menu.
- Adjustments (designated by Adj) are
made in the menu. To do so:
1. Activate the field by pressing SELECT.
2. Using the up or down arrow, adjust the
value.
3. Press SELECT to confirm the setting
and move on.
Selecting an operation mode
Some of the setting menus available for
selections depend on the mode of operation
you choose.
Pressing the right arrow button brings up the
initial selection menu so you can chose the
mode you need:
• Mixer mode: The system can mix up to
four mic/line inputs to each of the two output
channels for use in one or two zones.
• Stereo Select mode: With up to two
stereo sources connected and using both
output channels, the system provides stereo
sound to a single output zone.
• Dual Mono Select mode: With two input
souces connected to each of the two output
channnels, the system provides audio in two
zones.
• Utility - Includes system lockout and an
option to restore all settings to the factory
defaults.
POWER
switch
POWER
LED
Front control compartment
Rear connection panel
AC power cord
jack
Arrow
buttons SELECT button
Front control panel
Arrow buttons to
the right of the
LCD move forward,
back, up, and down
through menus.
An asterisk (*) marks
the selection made.

8
Specifications
Audio Inputs
Mic Inputs (4 - Balanced): Connectors: 3-pin Euroblock
Input Range: 20 - 20kHz
Input Impedance: 2k ohms (Mic)
25k ohms (Line)
Equivalent Input Noise: -122dB
Line Inputs (4 - Unbalanced): Connectors: Dual RCA (summed to mono)
Input Range: 20 20kHz
Input Impedance: 10k ohms
Maximum Input Level: +10dBu
Page Input (1 - Balanced): Connector: 4-pin Euroblock
Input Range: 20 - 20kHz
Input Impedance: 400 ohms
Equivalent Noise Input: -122dB
Direct Input (1 - Balanced): Connector: 3-pin Euroblock
Input Range: 20 - 20kHz
Input Impedance: 18k ohms
Maximum Input Level: +8dBu
Audio Outputs
Amplifier Outputs (2): Connectors: 5 Terminal Reverse
Euroblock
Minimum Load: 49 ohms @ 70V
98 ohms @ 100V
Output Impedance: 4 ohms
Aux Output (1): Connector: 3-pin Euroblock
Output Impedance: 400 ohms
Maximum Output Level: 2.2 dBV
Performance
Amplifier Power: 120W @ 4 ohms, 100W @ 70/100V
THD (at full rated power): < 0.5%
Crosstalk (below rated power, 1 kHz): < -60 dBV
Signal-to-Noise ratio: 75dB (below rated power, A-weighted)
Frequency Response: 40Hz - 16kHz (+0/-3dB)
Dynamic Range: 83dB
Sampling Rate: 44.1kHz

9
A/D and D/A Converters: 24-bit
Communication Port: RS-232 serial port
LED Status Indicators: Power - blue; Signal present - green; Clip - red
Power
Mains Voltage: 100 to 240VAC; 50 to 60Hz
AC Power Consumption: Idle: 39W
Active: 350W
Fuse Type: 120V T6.3A/250 or 240V T3.15A/250 L
DC Backup Power: +24V (+/- 1%)
Connector: 2-terminal barrier strip
Input Voltage Level: +24V
Minimum Input Power: 50W
Maximum Output Power: 150W
Mechanical
Dimensions: 3.5” H x 16.63” W x 13.5” D (8.9 x 42.2 x 34.3 cm)
Weight: Unpackaged: 31.8 lbs
Shipping weight: 39.9 lbs
Environmental
Operating Temperature: 0 - 40 degrees C
Storage Temperature: -40 - 70 degrees C
Humidity: 40 - 90%
Specifications (continued)

10
PART LIST NOTES
1. This part is not normally available from Customer Service. Approval from the Field Service
Manager is required before ordering.
2. The individual parts located on the PCBs are listed in the Electrical Part List.
3. This part is critical for safety purposes. Failure to use a substitute replacement with the
same safety characteristics as the recommended replacement part might create shock, fire
and/or other hazards.
4. This part is referenced for informational purposes only. It is not stocked as a repair part.
Refer to the next higher assembly for a replacement part.
ELECTROSTATIC DISCHARGE SENSITIVE (ESDS)
This unit contains ESDS devices. We recommend the following precautions when repairing,
replacing or transporting ESDS devices:
•Perform work at an electrically grounded work station.
•Wear wrist straps that connect to the station or heel straps that connect to conductive
floor mats.
•Avoid touching the leads or contacts of ESDS devices or PC boards even if properly
grounded. Handle boards by the edges only.
•Transport or store ESDS devices in ESD protective bags, bins, or totes. Do not insert
unprotected devices into materials such as plastic, polystyrene foam, clear plastic bags,
bubble wrap or plastic trays.
DEVICE HANDLING