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.
Bose Corporation; The Mountain, Framingham, Ma. 01701-9168
Service documentation available online at http://serviceops.bose.com
SERVICE BULLETIN
Date:
09/04
FINS:
1569
Q303
Component
From
Part Number
To
Part Number
R336
2.2 Ohm
133625-2R25
10 Ohm
133625-10R0
1N4148 Diode
R336
+10V
MMBT3906
Q304
MMBT3906
Q306
MMBT3906
Q307
AGND
IABC3
IABC2
IABC1
TP334
TP330
10uF
C311
1
2
100uF
C313
1
2
AGND
1.00K
R308
+10V
+15V
PGND
TP325
TP328
R313-NV
2SC4695
Q303
B
C
E
TP370
TP371
TP372
TP373
J301
1
2
3
TP375
TP376
TP377
TP378
249
R316
249
R317
249
R319
402
R337
2.2ohm
R336
13v
D301
A
C
C
A
Add Diode
