BOSE 294963-TT Schematic
REVISIONS
REV DESCRIPTION ENG DATE
00 INITIAL RELEASE BOB SMITH 5/09
SIGNATURES REQUIRED
TSG REPRESENTATIVE BOB SMITH
CELL LEAD
REPAIR SUPERVISOR
OTHER(________________)
TSG TECHNICIAN
Bob Smith
PRINT NAME SIGNATURE
KEVIN KING
DATE
5/09
FRAMINGHAM, MA 01701-9168
CLASS
FM
DWG NO.
294963-TT
APPLICABLE DOCUMENTS:
SERVICE MANUAL: 294963-SM
DESCRIPTION
SIZE
A
FreeSpace 4400 Amplifier
FSCM
32108
CLASS
FM
DWG NO.
294963-TT
PAGE 1 OF 5
REV
00
Troubleshooting Tips
FreeSpace® 4400 Amplifier
Refer to the FreeSpace 4400 amplifier service manual, reference number 294963-SM for
schematics, PCB layouts and parts lists. It’s located on the Service web site at
http://intranet.bose.com/tsg
Preventative Repair Measures
Note: Perform the following on all units returned for repair.
Product Check Action
FreeSpace
4400
amplifier
There are no preventative measures to perform on this amplifier.
or http://serviceops.bose.com on the Pro Products page.
Troubleshooting Tips
Product Symptom Check Action
FreeSpace
4400
amplifier
Outputs 1 and 2
and/or 3 and 4
fault LEDs lit.
System STATUS
LED is lit red
Ribbon cables
Output FETs
Amplifier setup
and installation
wiring
Error log for
amplifier module
fault conditions
Power supply
fuses
1. Verify that all of the ribbon cables that connect to
the DSP and the other boards are properly seated
into their connectors. Replace any damaged cables.
2. Check the outputs FETs on the upper and lower
amplifier boards. Verify that they are properly
secured to the heatsink and that they are not
shorted to it.
3. Check for a shorted speaker line in the
installation wiring.
4. Check that the source is not overdriving the
channel.
5. Check for loudspeaker transformer saturation.
Verify that the proper loudspeaker EQ’s are being
used.
6. Line voltage too high (surge). Check the unit’s
error log for an entry that the rail voltage exceeded
150V in 70V mode (US installs) or 190V in 100V
mode (Euro).
7. Live voltage too low (brownout) Using the
FreeSpace Installer software, check the unit’s error
log for an entry that the rail voltage was lower than
normal by at least 20%.
8. 70/100V mode switch position changed with unit
operating. Check that the output voltage setting (70
or 100V) is correct for the region the unit is used in.
Check that the AC input voltage selection switches
are set properly for the region.
9. Blown power supply fuse (not the AC line fuse).
Check the outputs FETs on the upper and lower
amplifier boards. Verify that they are properly
secured to the heatsink and that they are not
shorted to it. Replace the fuse and perform the test
procedures in the service manual. If the fuse blows
again, replace the amplifier module and retest.
Framingham, MA 01701-9168
SIZE
A
FSCM
32108
CLASS
FM
DWG NO.
294963-TT
SHEET
2 of 5
REV.
00
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