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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 CENTER OR OWNER OF THE
BOSE PRODUCT, AND SHALL NOT BE REPRODUCED OR USED
FOR ANY OTHER PURPOSE.
Contents
Safety Information ............................................................................................................................ 3
Specifications ................................................................................................................................... 4
Technical Description ................................................................................................................... 5-6
Figure 1. Equalizer Controls Response Charts ................................................................................6
Disassemble/Assembly Procedure ............................................................................................. 7-8
Figure 2. Staple Location .................................................................................................................7
Figure 3. Staple Removal Tool .........................................................................................................7
Figure 4. Wiring Diagram .................................................................................................................7
Figure 5. Top Cover ..........................................................................................................................9
Figure 6. Front Panel Assembly .......................................................................................................9
Figure 7. Indicator Lens Assembly ...................................................................................................9
Test Procedure .......................................................................................................................... 10-11
Figure 8. Test Set-Up .....................................................................................................................10
Part List ........................................................................................................................................... 12
Part List Notes ................................................................................................................................ 12
Figure 9. 901 I Schematic Diagram ................................................................................................13
Figure 10. 901 II Schematic Diagram .............................................................................................14
Figure 11. 901 Schematic Diagram (first production run) ...............................................................15
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3 CAUTION: THE BOSE
¨ 901 I and II EQUALIZERS CONTAIN NO USER-SERVICEABLE
PARTS. TO PREVENT WARRANTY INFRACTIONS, REFER SERVICE TO WARRANTY
SERVICE STATIONS OR FACTORY SERVICE.
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 ÒLeakage Current for AppliancesÓ and Underwriters Laboratories
(UL) 1492 (71). With the unit AC switch first in the ON position, then in the
OFF position, measure from a known earth ground (metal water pipe,
conduit, etc.) to all exposed metal parts of the unit (antennas, handle bracket,
metal cabinet, screw heads, 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 HAZ-
ARD 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 be-
tween the jumpered AC plug and each exposed metallic cabinet part on the
unit. When the exposed metallic part has a return path to the chassis, the
reading should be between 1 and 5.2 Megohms. When there is no return path
to the chassis, the reading must be ÒinfiniteÓ. If it is not within the limits specified,
there is the possibility of a shock hazard, and the unit must be repaired and re-
checked before it is returned to the customer.
