Bose FreeSpace Business E4 II Series Service Manual page 107

Service Bulletin
®
FreeSpace 4400 Amplifier Module Installation
• Place the new heatsink adapter brackets onto the two
remaining metal studs. The bent edges should face down.
Refer to the photo at right. Place the nuts onto the studs over
the brackets. Do not tighten these nuts at this time.
• Connect the AC power transformer and the fan wiring
harnesses to the bottom amplifier PCB assembly.
• Slide the FreeSpace 4400 amplifier module assembly
heatsink under the two adapter brackets. See photo at right.
• Using the four new screws from the adapter kit, secure the
amplifier module to the chassis rear panel.
• Re-install the three screws that secure the amplifier module
to the chassis standoffs. Tighten the two nuts that secure the
heatsink to the chassis.
• On the back of the E4 Series II chassis, verify that the output
voltage select switch is set to the correct position. It should be
set to 70V for US/Canada units and 100V for non-US units.
EMI Gasket Installation
Note: Installation of this gasket is required to suppress RF noise
from the unit to the required level. Failure to install the gasket
could result in excessive system noise at the customer's site.
• Disconnect the LED harness at J510 on the DSP PCB.
• Remove the six screws that secure the DSP, Wall Plate
Sense and Auto Volume PCBs to the rear panel. Remove the
two standoffs that secure the RS232 connector.
• Remove the two screws that secure the DSP PCB to the
bottom of the chassis and carefully lift all of the PCBs out of
the chassis together.
• Place the provided EMI gasket over the four RCA analog
input jacks on the DSP PCB. Note: Be sure that the side of
the gasket with the fibrous sheet attached faces the chassis.
This is necessary to provide correct EMI attenuation.
• If necessary, remove any paint overspray that may be on the
inside of the chassis at the RCA jack chassis holes. Any paint
present at that location would prevent the EMI gasket from
making a good EMI ground.
• Re-install the DSP / Wall Plate / Mic Sense board stack into
the chassis using the screws removed previously. The EMI
gasket will compress once the screws are in place.
• Connect the large ribbon cable to the DSP PCB at JH501.
• Re-install the chassis top cover.
• Perform the test procedures located in the E4 Series II
service manual, reference number 278977-SM, to ensure
proper operation of the unit before returning it to the customer.
Bose Corporation; The Mountain, Framingham, Ma. 01701-9168
For Technical Assistance Call 1-800-233-4408
Service documentation available online at http://serviceops.bose.com