SERVICE BULLETIN
Bulletin Part Number: 271885-B2
Product: Companion®3 Multimedia Speaker System
Subject: No Audio Output
Disposition: All units in for repair with a no audio complaint.
Symptom: No audio output from the system and the control pod LED is dimly lit.
Reason: Q303 on the main PCB is defective or shorted completely.
Solution:Replace Q303 with part number 148770. Add a 1N4148 diode part number 121501 across the base and emitter junction. Polarity is very important. Connect the cathode of the diode to the base and the anode to the emitter. Refer to the figures below for the location of Q303 and orientation of the diode. Also replace R336, as identified in the table below. Refer to the Companion 3 Speaker System service manual part number 271885-SM.
Component |
From |
Part Number |
To |
Part Number |
R336 |
2.2 Ohm |
133625-2R25 |
10 Ohm |
133625-10R0 |
1N4148 Diode
Q303 |
R336 |
Date: 09/04
FINS: 1569
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+15V |
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+10V |
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TP334 |
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R336 |
TP378 |
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+10V |
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J301 |
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R308 |
2.2ohm |
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C |
Q303 |
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R337 |
R316 |
R317 |
R319 |
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B |
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1 |
TP372 |
TP373 |
TP325 |
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TP328 |
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402 |
249 |
249 |
249 |
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TP371 |
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C |
2SC4695 |
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TP370 |
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1.00K |
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2 |
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A |
E |
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TP376 |
TP377 |
TP375 |
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3 |
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Add Diode |
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TP330 |
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MMBT3906 |
MMBT3906 |
MMBT3906 |
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Q304 |
Q306 |
Q307 |
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1 |
C311 |
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R313-NV |
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10uF |
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IABC3 |
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D301 |
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2 |
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1 |
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PGND |
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C |
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13v |
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C313 |
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100uF |
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IABC2 |
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A |
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2 |
AGND |
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IABC1 |
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AGND |
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Bose Corporation; The Mountain, Framingham, Ma. 01701-9168
Service documentation available online at http://serviceops.bose.com
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