ACOUSTIMASS®-3 POWERED
SPEAKER SYSTEM
©
1992 Bose Corporation Service Manual
TABLE OF CONTENTS
Note: This service manual has been updated with information from service manual supplement
175032-S2. This supplement affects part number for R146 and R246 as used on the amplifier PCB.
Refer to 175032-S2 for more information.
1. SAFETY INFORMATION.......................................................................................... 2
2. SPECIFICATIONS.................................................................................................... 3
3. BLOCK DIAGRAMS.................................................................................................. 5
4. THEORY OF OPERATION....................................................................................... 6
5. DISASSEMBLY/ASSEMBLY PROCEDURES......................................................... 13
6. TEST PROCEDURES.............................................................................................. 19
7. PARTS LISTS AND EXPLODED VIEWS................................................................. 23
8. SCHEMATICS AND PCB LAYOUTS....................................................................... 39
CAUTION: THE ACOUSTIMASS®-3 POWERED SPEAKER SYSTEM
CONTAINS NO USER-SERVICEABLE PARTS. TO PREVENT
WARRANTY INFRACTIONS, REFER SERVICING TO WARRANTY
SERVICE STATIONS OR FACTORY SERVICE.
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.
1
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 "Leakage Current for Appliances" and Underwriters Laboratories
(UL) 1492 (71). With the unit AC switch first in the ON position and then in
OFF position, measure from a known earth ground (metal waterpipe,
conduit,etc.) to all exposed metal parts of the unit (antennas,handle bracket,
metal cabinet,screwheads,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 HAZARD
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 between 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 "infinite". If it is not within the limits specified, there is the possibility of a shock hazard, and the unit must be repaired and rechecked before it
is returned to the customer.
2
SPECIFICATIONS
Dimensions Module: 7.75"H x 18.5"W x 8.5"D (20x47x22 cm)
Satellite: 4.5"H x 4.5"W x 3.5" D (11x11x9 cm)
Weight Module: 21 lbs. (9.5 kg.)
Satellite: 1.3 lbs. (0.6 kg.)
Packed System: 27 lbs. (12.3 kg.)
Driver 1-5-1/4" Woofer
Complement 2-2-1/4" Twiddlers
Finish Module: Black or white,scratch-resistant,satin-finished
vinyl
Satellites: Black or white,painted polymer finish
PERFORMANCE SPECIFICATIONS
Amplifier Power Woofer (single): 50 watts into 5Ω resistive load,
≤0.2% THD, from 40-200 Hz
Input Impedance System: 5.9kΩ ± 4%
Distortion @ 1W <0.1% THD (all channels
Output Noise <180µVrms A weighted for L/R channels
Output Hum <500µVrms Unweighted for bass channel
Channel @1kHz >40 dB
Separation @10 kHz >30 dB
Port Tuning Small Chamber: 110 Hz
Frequency Large Chamber: 43 Hz
Input Sensitivity 0.6 Vrms input @1kHz produces rated power in L/R channel
Turn-On Delay 80ms ± 40 ms
(Auto)
Satellites (each): 20 watts into 4Ω resistive load,
≤0.2% THD, from 200Hz-15kHz
Satellites: 4Ω
Woofer: 5Ω
outputs (at full volume)
Turn-Off Delay 100 sec. ± 20 sec.
(Auto)
Acoustic Output: 97 dB SPL in IEC standard room @ 50W
3
Frequency Response Curves
Figure 1. Bass Channel Frequency Response Curve
Figure 2. Left/Right Channel Frequency Response Curve
4
BLOCK DIAGRAM
Figure 3. AM-3P Amplifier PCB Assembly Block Diagram
Figure 4. AM-3P Equalizer PCB Assembly Block Diagram
5
AM-3P THEORY OF OPERATION
NOTE: The following discussion references the AM-3P EQ and Amplifier schematics and
block diagrams. The block diagrams,Figures 3 and 4, can be found on page 5 and the
schematics are located in the back of this service manual.
GENERAL
The AM-3P powered Acoustimass loudspeaker system is designed to be used with the BOSE
Lifestyle Music Center (or other line level audio source) to form a simple, yet complete, home
audio system. The AM-3P is based acoustically on the AM-3 Acoustimass (unpowered)
loudspeaker system. The AM-3P, like its big brother, the AM-5P, offers many advantages over
a separately powered AM-3 system. These include:
- Automatic turn-on/ turn-off (mute) of the amplifier output stage
- Automatic (BOSE patented) dynamic equalization
- Bi-amplification for better power distribution to speakers
- Active equalization for smoother frequency response
- Amplifier short-circuit and DC offset fault protection
- Local volume/sensitivity control
- Bass/treble room compensation controls
- Differential input stage (to reject hum)
- Dynamic compressor to prevent amplifier output overload distortion
BLOCK DIAGRAM DESCRIPTION
NOTE: In the discussion of L/R (left/right) channels,only the right channel is discussed. The left
channel operation is identical.
1. Power Supply
A single, universal, 115/230V EI core power transformer is used to power the system. It has
been specially designed for minimum magnetic flux leakage and stand-by power consumption.
The transformer primary remains energized (always on) except when the power switch is in the
off position.
The two primary windings of the transformer are wired in series for 230V operation, and in
parallel for 115V operation, depending on the position of the customer accessible voltage
select switch. If the system is accidentally energized at 230V with the switch in the 115V
position, the replaceable fuse (F1 located on the Equalizer PCB assembly), will open the
circuit within 2 minutes. This will be the only damage to the system.
6
A non-serviceable thermal fuse is located inside the transformer to limit the maximum
temperature to 145 °C under abnormal conditions. However, in most cases the external fuse
(F1) should fail before the internal transformer thermal fuse. The thermal fuse can be checked
by measuring the continuity between pins 1 and 4 (black and white wire) of the primary
connector. This connector is located on the Equalizer PCB.
2. Differential Input Stage
Audio input applied at the phono jack (J8) connects directly to the right (left) differential amplifier
buffer. This stage accomplishes several functions:
- Provides rejection of common-mode interference (such as hum) that might be picked up
by the long audio cable between the AM-3P and lifestyle music center
- Provides input overload and ESD protection through diodes (D101-104)
- Removes radio frequency Interference through C103,125,127
- Provides DC blockage by C101,102
- Provides a 6 dB gain through op-amp U101.
3. Compressor/Treble Stage
U102 (pins 1,2,3), with potentiometer VR2 at the center position, operates as a conventional
inverting operational amplifier stage with a gain of 6 dB. However, when voltage overload is
present at the speaker outputs, transistor array U1 (pins 1,2,3) receives a turn-on signal from
the compressor detect stage. Under this condition, the transistor acts as a variable resistor
to ground, and with R107, forms a resistor divider network that attenuates the audio signal.
The amount of attenuation and timing action is carefully controlled by the compressor detect
stage (to be discussed later).
Potentiometer VR2 adjusts the amount of treble boost or cut. In the full counterclockwise
position, the wiper (pin 4) shorts to pin 1. The maximum boost and cut frequency response
graph is shown in Figure 2 on page 4.
4. High Frequency (HF) Equalization
High frequency equalization and crossover is achieved through three cascaded active EQ
stages. These stages consist of U103,U104 and U105. The purpose of equalization is twofold:
- It provides very sharp low frequency attenuation below 200 Hz (the crossover frequency)
to prevent overload of the L/R speakers
- It provides finely tailored correction in the speaker pass-band so that overall frequency
response of the system is acoustically correct.
7
The U103 stage is a combination 2nd order 200 Hz high-pass filter and 5 dB 2 kHz dip (notch)
filter. The U104 stage provides the 5 dB peak at 200 Hz and the sharp band-reject between
100 and 200 Hz. Finally, the U105 stage is a combination 2
nd
order 20 kHz low-pass filter and
2 dB 350 Hz notch filter.
5. Bass Control
The bass channel signal is derived from the sum of the left and right channels through resistors
R129 and R229 and through inverting op-amp summer U2. Potentiometer VR3 simply adjusts
the gain of the stage between -6 dB to +6 dB. In the flat (center) position of the control ,the gain
is 0 dB. Adjusting the bass by varying the gain of the overall bass channel has been determined
to be acoustically appropriate to compensate for various placement options of the bass module.
6. Automatic Dynamic Loudness
In order to compensate for the ear’s loss of bass response at low listening levels, a BOSE
patented (4,739,513) automatic loudness circuit is employed. This circuit automatically senses
the volume level of the incoming audio signal and properly adjusts the amount of low frequency
bass boost. When the volume level is high, the frequency response of the circuit is flat. When
the volume level is decreased (at the music center), the low frequency gain is increased in the
region between 50 and 150 Hz (see the bass channel frequency response graph on page 4).
This loudness contour, and the time constants associated with it, have been precisely
determined through psycho-acoustic testing and should not be confused with other conventional loudness schemes.
Circuit operation is as follows: Left and right audio output at pins 7 and 1 of U101 are summed
together by resistors R132 and R232. The AC signal at pin 3 of level detect op-amp U2 is
negative-peak detected and is presented across emitter resistor R9. The peak detected signal
has a (approximate) 4 second hold time and a 4 sec/10 dB release time constant which is
developed within the feedback loop of U2 (pins 1,2,3). The voltage across R9 is converted to
a current source through transistor Q3, and flows into pin 5 of transconductance amplifier U4.
U4 is placed in the feedback loop of op-amp U3 to create an inverse voltage controlled
bandpass stage such that increased current into pin 5 of U4 causes the gain of the band-pass
stage to decrease. The 55 Hz band-pass filter consists of resistors R10,11 and 15 and
capacitors C6 and C7. At frequencies above 200 Hz, the stage acts as a unity gain follower
(flat frequency response) through resistors R16,17, and 18. The over-all loudness contour
response is visible at U3 pin 1.
7. Low Frequency (LF) Equalization
Low frequency bass channel equalization and crossover is accomplished in two active filter
stages. The first stage consists of op-amp U3 (pin 5,6,7),capacitors C9 and 10 and resistors
R19,20, and 21. It creates the sharp band-reject attenuation below 50 Hz. The second stage
consists of op-amp U5 (pin 1,2,3,), capacitors C13 and 14, and resistors R24,25,26 and 27. It
acts as a combination 2
nd
order 50 Hz high-pass and 200 Hz low-pass filter. The combined
response of these two stages is shown in the bass channel frequency response graph in Figure
1 on page 4.
8
8. Auto Turn-On/Off Mute
An improved version of auto turn-on/off is used in the AM-3P. A separate 3.5 mm stereo minijack (J7) is used to receive the turn-on signal from the serial data output of the Lifestyle music
center. When the 3.5 mm plug is inserted, the audio sense circuit is disabled and the amplifier
outputs will only unmute if the DC control signal is present at J7 pin 3. This action occurs
through the built-in DPDT switch in J7 which connects J7 pin 3 directly to the Q9 mute circuit.
Therefore, the system is not subject to random false turn-on (from electrical noise, etc.) when
used with the Lifestyle music center.
When the AM-3P is used with a source other than the Lifestyle music center,the stereo miniplug is not inserted into the jack, and therefore mute transistor Q9 is directed to the output of
the audio detect comparator U6 (pin 5,6,7). This comparator uses hysteresis to achieve a
positive turn-on of at least 90 seconds before the system will revert to stand-by (mute) mode
after removal of the audio signal.
9. Compressor Detect
The output of each left/right amplifier is half-wave detected through diodes D108 and 208. This
voltage is divided down by R53 and R54 and presented at the emitter of Q12. Power supply
voltage is similarly divided down by R50 and R51 and presented at the base of Q12. Diodes
D13 and D14 simulate the saturation voltage drop that occurs in the power amp stage.
Therefore, when the audio output of any amplifier comes within 2 volts of the instantaneous
power supply voltage, Q12 will conduct.This signals the compressor (limiter) to act. Current
from Q12 charges hold capacitor C35 and releases capacitor C36. Voltage at C35 is buffered
by transistor U1 (pins 5,6,7) and decreased down to a logarithmic voltage by resistor R67 and
diode U1 (pins 12,13,14). This voltage is then presented to the base of compressor transistors
U1 (pins 1,2,3) and U1 (pins 8,9,10) which are described in the compressor section.
The DC control voltage present across capacitor C35 is derived through the use of an improved
hold and release characteristic, resulting in lower compressor distortion. In conventional
limiters, this DC control voltage is derived by a simple series diode and parallel RC network to
ground. Unfortunately, for low frequency overload, this results in substantial ripple voltage
present on the DC gain control voltage. This results in the all too common problem of mid-range
voices or instruments being badly “modulated” by low frequency overload. This problem is
solved by having two separate capacitors, one that “holds” the smooth DC voltage just long
enough to prevent low frequency ripple (approximately 40ms) and the other (C36) which quickly
releases the hold capacitor (through diode D17) at the proper time to maintain overall 100ms
release time.
9
10. Power Amp (Amplifier PCB)
Four identical topology class B, power amplifier stages are used to create the three power
amplifier channels. One each is used for the left and right power amplifiers (2 x 20W into 4
Ohm), and two are used in bridged mode for the bass channel to create 50W into 5 Ohm.
Operation of the left channel (representative) is as follows:
A positive signal at op-amp input U106 pin 3 causes op-amp supply current to flow into pin
7 (and out through pin 6) through Q103. Q103 is used simply to buffer the +20V high voltage
supply down to a safe +7.4V for the op-amp. This current also flows through R132 and diode
D105. R132 and D105, together with driver transistor Q105 and R134 form a current mirror
which multiplies the current through Q103 by the ratio R132/R134. This increased current flows
through driver transistor Q105, and into the base of output transistor Q107. The hFE current
gain of output transistor Q107 (about 100) provides final current amplification before reaching
the speaker output.
The power amplifier topology is complementary.Therefore,operation of the amplifier on
negative half cycles is identical to positive cycle operation, except for component reference
designations.
11. Short-Circuit Protection
Left and right power amp stages have short circuit protection. This is necessary to prevent
damage to the amplifier from customer misuse that might occur, for instance, if the customer
were to accidentally short the speaker cable wires that connect to the cube speakers. If this
happens, all three amplifiers will momentarily mute for about 3-4 seconds and continue to mute
until the abnormal condition is removed.
Short circuit protection is achieved with the use of a .1
Ω resistor (R146 for left channel) in series
with each amplifier output. Under normal conditions, peak current to the 8 Ω speakers should
never exceed 3.5A. If current flow momentarily exceeds 5.0A, then Q109 will conduct and
trigger monostable multivibrator circuit U5 (pins 5,6,7)on the Equalizer PCB. Pin 7 will go high
(for about 3 seconds) and through diode D12 will trigger mute transistor Q10. Turn-on of Q10
causes all three amplifiers to mute. Referring to the left channel power amplifier, actual muting
occurs by turning on transistors Q110, 101, and 102 which cause both driver transistors (Q105
and Q106) to turn off. When the driver transistors are off, there can be no current flow through
the output transistors, which results in no current flow to the speaker.
10
12. DC Offset Protection
If any one of the three amplifier channels should fail, it is likely that a large DC voltage will occur
at the output of that channel. If this occurs, the DC offset detect circuit will cause the AM-3P
amplifier power supply to shut down. It will remain shut-down until the unit is unplugged from
the power source. This provides a safe indication to the customer that the unit requires service.
Detailed operation is as follows: The amplifier outputs are summed by resistors R149,249,318,
and 418, and (low pass) filtered by capacitor C29. For a sustained DC offset, C29 will charge
either negative or positive. A positive offset will trigger Q7 and a negative offset will trigger Q8.
This in turn causes Q6 to conduct and latches Q5 permanently on. Q5 then shorts the emitter
of Q4 to ground (off). Q4 is the transistor that controls turn-on of 2P1T relay K1 (on the Amp
PCB) that is used to connect +/- 20V supply rails to the power amplifiers. Thus, the amplifiers
are de-energized.
11
NOTES FOR FUTURE REFERENCE
12
AM-3P DISASSEMBLY/ ASSEMBLY PROCEDURES
Module Procedures
1.Cover Removal
NOTE: Refer to Figures 5 and 6 for an exploded
view of the module. Certain parts will be referred
to in these procedures. The item number which
corresponds to the part will be enclosed in
parentheses-i.e.-heatsink (9).
A. Remove the cover cap (1) either by using the
flat edge of a screwdriver or your fingers. Find
the recess on one side of the cap and lift the cap
up and away from the cover (3).
B. Remove the screw (2) located under the cover
cap.
C. Pull the 3 (friction fit) control knobs (4) directly
out from the module.
D. Stick your fingers into the control knob holes.
Swivel the cover carefully away from the
connector panel and pull it away from the
module.
2. Cover Replacement
A. Hook the cover (3) into place by slanting the
cover slightly forward (with connector panel
facing you) and aligning the appropriate holes
with the connector panel.
3. EQ PCB Assembly Removal
A. Remove 1 screw (6) which secures the PCB
(5) to the adapter bracket (8).
NOTE: The connector gasket (7) has a light
adhesive backing. Be careful not to tear it during
removal.
B. Pull the connector gasket carefully away from
the connector panel.
C. Release the PCB from the 4 adapter bracket
snaps (not shown),one edge at a time.
D. Unplug the flat,16-pin cable (13) which is
connected to the Amplifier PCB (11).
NOTE: The J5 connector pins fit snugly into the
mating connector housing. Take care when
attempting to unhook this connector.
E. Disconnect the 5-pin connector housing, J5,
(which is connected to the transformer
assembly’s (18) primary side),by pulling the PCB
carefully up from the unit. Unhook the connector
housing from the slot on the adapter bracket.
4. EQ PCB Assembly Replacement
B. Snap the cover into place.
C. Replace the 3 control knobs (4) by pushing
them in towards the module.They are keyed and
will only fit one way.
D. Secure the cover to the module with 1 screw
(2).
E. Hook the cover cap (1) into place. The
notched edge must align with the module’s label
side.
A. Hook the J5 connector housing into the slot on
the adapter bracket (8).
NOTE: Connector J5 has a unique keying feature
and can only be re-connected one way.
B. Lower the PCB (5),solder side up,into position.
The PCB’s connector panel must align with the
module’s label side. Make sure that the pins on
connector J5 line up with its mating connector
housing (transformer primary wires).
13
C. Push down the corners of the PCB until all 4
adapter bracket snaps (not shown) engage.
Make sure that the J5 connector pins are
completely re-connected to the mating connector
housing.
D. Secure the heatsink and adapter bracket to
the module with 6 screws (10).
7. Amplifier PCB Assembly Removal
D. Plug in the flat,16-pin cable (13) to the PCB.
E. Secure the PCB to the bracket with 1 screw
(6).
F. Place the connector gasket (7) over the
connector panel.
5. Adapter Bracket and Heatsink Removal
NOTE: It is only necessary to remove 3 screws
(10) to remove the adapter bracket (8). These
screws are located on the same side as the
module’s labels. The bracket hooks onto a flange
that is part of the heatsink (9). If further teardown
of the unit is required,then all 6 screws (10)
should be removed.
A. Remove 6 screws (10) that secure the adapter
bracket and the heatsink to the module.
NOTE: It is not necesary to completely tear down
the unit to access the Amplifier PCB (11). Follow
the simplified steps A-D below if direct access to
this PCB is required and you have not already
disassembled the unit.
A. Remove the cover (3) using Procedure 1.
B. Unplug the flat,16-pin cable (13).
C. Remove 6 screws (10) which secure the
adapter bracket (8) and heatsink (9) to the
module.
D. Lift the EQ PCB (5),adapter bracket and
heatsink away from the module.
NOTE: The EQ PCB should remain connected to
the transformer primary side. It should also
remain secured to the adapter bracket with 1
screw (6).
B. Pull the bracket and heatsink away from the
module.
NOTE: The Amplifier PCB Assembly (11) may be
stuck to the heatsink with thermal grease.
6. Adapter Bracket and Heatsink Replacement
A. Lower the heatsink (9) into position on top of
the Amplifier PCB (11). Make sure that the side
of the heatsink with smaller fins is aligned with
the module’s label side.
B. Align the screw holes on the heatsink with
those on the transformer cup (19).
C. Hook the bracket onto the heatsink
flange.Lower the adapter bracket (8) into
position. The bracket has screw holes only on
one side. These should be aligned with the screw
holes on the module’s label side.
E. Lift up the Amplifier PCB (11) and unhook
connectors J1 and J4 from the PCB. J4 is
connected to the woofer and J1 is connected to
the transformer assembly’s (18) secondary side.
Pull the PCB away from the unit.
F. Remove the 2 transistor spring clips (14)
which rest on the transformer cup (19).
8. Amplifier PCB Assembly Replacement
A. Place the 2 transistor spring clips (14) on the
transformer cup (19).
B. Re-connect connector J4 to the safetycontrolled woofer cable (24) and connector J1 (5
pin) to the transformer assembly’s (18)
secondary side.
NOTE: The Amplifier PCB (11) has large
capacitors which will only fit into one side of the
transformer cup (19).
14
C. Lower the PCB (solder side up) into place on
top of the transformer cup. There are holes in
each corner of the PCB that align with the locater
pins on the cup.The transistors (on PCB edges)
should rest lightly on the transistor spring clips
(14). Place the transformer primary connector
wires into the slot on the PCB.
B. Align the screw holes on the transformer with
those on the cup.
C. Secure the transformer to the cup with 4
screws (15) and 4 washers (16) using a 3/32-inch
Allen wrench.
NOTE: If no further servicing is required,use the
simplified steps below to re-assemble the unit.
D. Replace the heatsink (9) using Procedure
6,steps A. and B.
E. Place the transformer primary into the slot on
the Amplifier PCB (11).
F. Replace the adapter bracket (8) and EQ PCB
(5) and secure using Procedure 6,step C.
G. Secure the heatsink, adapter bracket and EQ
PCB to the module with 6 screws (10).
H. Replace the cover (3) using Procedure 2.
9. Transformer Assembly Removal
NOTE: If direct access to the transformer is
required and the unit has not been
disassembled, refer to the simplified steps
provided in Procedure 7, along with steps A.
and B. below.
NOTE: If no further servicing of the unit is
required,refer to the simplified steps provided in
Procedure 8 to re-assemble the unit.
11. Transformer Cup and Gasket Removal
NOTE: To directly access the transformer cup
and gasket,follow the simplified steps provided in
Procedure 9,then proceed with steps A. and B.
of this procedure.
A. Remove 2 screws (10) which secure the
transformer cup (19) to the module and lift the
transformer cup away from the module.
NOTE: There might be woofer connector wires
(safety controlled cable-(24)) taped over the
transformer cup gasket (20). Note the location of
the cable relative to the module. Remove the
tape and move the wires aside.
B. Remove the transformer cup gasket .
12. Transformer Cup and Gasket Replacement
A. Remove 4 screws (15) and 4 washers (16)
using a 3/32-inch Allen wrench and lift the
transformer assembly (18) out of the transformer
cup.
NOTE: With the module’s label side facing you,
the transformer’s primary side is on the left and
the secondary side is on the right.
10. Transformer Assembly Replacement
NOTE: The transformer bracket (part of the
assembly) has a bent flange in corner which will
only allow the transformer to fit 1 way in the
transformer cup (19).
A. Lower the transformer assembly (18) into the
transformer cup.
NOTE: The transformer cup gasket (20) has
raised edges which should be facing up when
positioning the gasket. The gasket also has a Ushaped opening which will align precisely with
the module.
A. Place the gasket in position over the opening
of the module.
B. Lay the woofer cable (24) over the appropriate
corner of the bass module. The wires must cross
over the top of the gasket.
C. Position the transformer cup. The cup has a
locating ridge and only fits into the module one
way. The lip should be aligned with the U-shaped
opening in the module.
15
D. Secure the cup to the module with 2 screws
(10).
NOTE: If no further servicing of the unit is
required,refer to the simplified steps provided in
Procedure 10 to re-assemble the unit.
13. Woofer Removal
C. Re-mount the woofer (21) to the module using
4 screws (22). Repeat the woofer test
procedures.
NOTE: If no further servicing of the unit is
required,use the following simplified procedures
to re-assemble the unit.
NOTE: If direct access to the woofer is required
and the unit has not already been
disassembled,follow the simplified steps A.-D.
given below.
A. Remove the cover (3) using Procedure 1.
B. Remove the EQ PCB (5),heatsink (9) and
adapter bracket (8) using Procedure 7,steps C.
and D.
C. Lift up the Amplifier PCB (11) and unhook the
safety controlled woofer cable (24) from
connector J4 (Amplifier PCB).
D. Remove the transformer cup (19) and gasket
(20) using Procedure 11.
E. Remove 4 screws (22) which secure the
woofer (21) to the baffle (part of the module).
14. Woofer Replacement
D. Replace the transformer cup (19) and gasket
(20) using Procedure 12.
E. Replace the transformer assembly (18) using
Procedure 10.
F. Re-install the Amplifier PCB (11) using
Procedure 8.
G. Re-install the heatsink (9) and adapter bracket
(8) using Procedure 6.
H. Re-install the EQ PCB (5) using Procedure 4.
I. Replace the cover (3) using Procedure 2.
Satellite Procedures
NOTE: Refer to Figure 7 for an exploded view of
the satellite. Certain parts will be referred to in
these procedures. The item number which
corresponds to the part will be enclosed in
parentheses-i.e.-baffle (9).
A. Carefully lift the woofer out and cut the wires
connected to the woofer terminals as close to the
terminals as possible.
NOTE: Make a note of the woofer terminal
orientation relative to the module. The woofer
should be re-positioned in its original location.
B. Strip the wires and connect to a replacement
woofer. Make sure that the red wire is connected
to the positive (+) terminal and the black wire is
connected to the negative (-) terminal. When repositioning the woofer,make sure that the woofer
gasket (23) is correctly positioned behind the
woofer to make an airtight seal.
1. Grille Removal
A. Grasp the top and bottom of the grille and
grille frame (1,2). Pull the assembly carefully
away from the satellite.
2. Grille Replacement
A. Align the grille feet (not shown) with the 4
holes in the satellite enclosure. Push the
assembly gently into place.
16
3. Twiddler Removal
5. Terminal Cover Removal
A. Remove the 4 screws (4) holding the twiddler
(3) in place. Lift the twiddler out and cut the wires
connected to the twiddler as close to its terminals
as possible.
4. Twiddler Replacement
A. Strip the wires and connect to the replacement
twiddler (3).
NOTE: The positive (+) terminal of each twiddler
is marked with a red dot.
B. Connect the red wire to the positive (+)
twiddler terminal and the black wire to the
negative (-) twiddler terminal.
C. Lower the twiddler into the satellite enclosure
and secure the twiddler to the enclosure with 4
screws (4). Repeat the satellite test procedures.
NOTE: There are catches on the top and bottom
(inside) of the terminal cover (7) that hook it into
the satellite enclosure. Take care when removing
the cover.
A. Using your fingers or the flat edge of a
screwdriver,pull the terminal cover carefully from
the satellite enclosure using the recesses in the
cover.
6. Terminal Cover Replacement
A. Snap the terminal cover (7) carefully into place
on the satellite enclosure.
7. Connector Removal
A. Remove 2 screws (4) which hold the
connector in place.
8. Connector Replacement
A. Secure the connector (6) to the satellite
enclosure with 2 screws (4).
17
NOTES FOR FUTURE REFERENCE
18
AM-3P TEST PROCEDURES
Satellite Test Procedures
NOTE: Use these procedures only when
satellites come in to be serviced (without the
bass module).
1. Sweep Test
A. Connect an oscillator to a power amplifier.
Adjust the amplifier output to 4 Vrms. Connect
the amplifier leads to the satellite (cube speaker)
input terminals. Sweep the oscillator from 100 Hz
to 5 kHz. If any twiddler buzzes or sounds
distorted,replace it.
2. Phase Test
NOTE: Supply voltage should only be
momentarily applied to the satellite input
terminals to avoid possible damage to the
twiddlers.
A. Set a DC power supply to 8 volts. To ensure
that each twiddler is connected in phase, connect
the positive supply lead to the positive (+)
satellite input terminal (red) and the negative
supply lead to the negative (-) satellite input
terminal (black). The twiddler should move
outwards with the application of the supply
voltage.
1. Turn-On Test
NOTES: Refer to the AM-3P EQ PCB schematic
for the location of the J7 mini-jack input,pins 1
and 3. It is contained in the On/Off Control
circuit on this schematic.
This test can be performed with a fully
assembled module.
This procedure also refers to the “ring” and
“sleeve” of a standard 3.5 mm mini-jack.
A. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 500
Hz,220 mVrms.
B. Insert a 3.5 mm mini-jack into the input
terminal labeled “System Control”. The audio
signal should mute.
C. Set a DC power supply to 8 volts and apply
this voltage between pins 3 (ring) and 1(sleevewhich is connected to ground) of the mini-jack.
The audio signal should return.
2. Sweep Test
NOTE: This test can be performed with a fully
assembled module.
NOTE: If any twiddler cone deflects inwards or
does not move,check all connections.
Woofer (Module) Test Procedures
NOTES: Use these procedures only when a
module comes in to be serviced (without
satellites). All tests should be performed with the
bass and treble control knobs in the normal or
"detent" position and the volume control knob at
maximum volume.
It may be necessary to disassemble the module
in some of these procedures. Refer to the
Disassembly/Assembly Procedures section for
specific instructions.
A. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 100
Hz,220 mVrms. Sweep the oscillator from 10300 Hz. There should not be any
loud,extraneous sounds. If there are any loud
buzzes or distortion,replace the woofer.
NOTE: There should not be any buzzes or rattles
from within the module. Redress any wire or
component that buzzes or rattles.
19
3. Tone Control Test
Frequency Relative Response
1 kHz 0 dB
NOTE: This test can be performed with a fully
assembled module.
A. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 100
Hz,220 mVrms.
B. Rotate the bass control knob fully clockwise
and counterclockwise from its center or “normal”
position. The bass level should increase and
decrease cleanly without making a scratchy
noise. Clean or replace any potentiometer that
makes this noise.
C. Repeat this procedure for the treble control
using a frequency of 4 kHz.
4. Frequency Response of L/R (Twiddler) Channels
NOTE: This test can be performed with a fully
assembled module.
A. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 1
kHz,200 mVrms. Connect a piece of test
equipment capable of measuring decibels to
either the left or right twiddler output terminals
(labeled “To Cube Speakers”). Measure the dBs
at this setting and use as a 0 dB reference.
2 kHz -5.2 dB ± 1.5 dB
10 kHz +1.0 dB ± 1.5 dB
20 kHz -1.4 dB ± 2.0 dB
5. Twiddler Power Output Test
NOTE: This test can be performed with a fully
assembled module.
A. Connect a 4Ω resistive load across either the
left or right twiddler output terminals (labeled “To
Cube Speakers”). Connect a voltmeter across
the load.
NOTE: These measurements can be obtained at
120 and 240 V. Results will vary depending on
the line voltage used.
B. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 1
kHz, 549 mVrms.
C. Measure the voltage across the load. It should
be approximately 8.9 volts (20 watts).The signal
should look undistorted when viewed on an
oscilloscope.
B. Once connected to either the left or right “cube
speaker” output terminals,adjust the oscillator
frequency and measure the relative response
according to the chart located at the end of this
procedure.
C. Repeat this test for the other channel.
Frequency Relative Response
100 Hz -16.0 dB ± 2.0 dB
200 Hz +5.7 dB ± 1.5 dB
360 Hz -2.0 dB ± 1.5 dB
6. Twiddler Short Circuit Protection Test
NOTES: This test can be performed with a fully
assembled module.
Do not short out for longer than 1 second.
A. Adjust the oscillator to 1 kHz, 200 mVrms.
Short the left or right twiddler output terminals.
The signal should mute for approximately 3
seconds.
20
7. Air Leak Test
9. Woofer Phase Test
NOTE: Part A. of this test can be performed with
a fully assembled module.
A. Connect an oscillator to the module’s left/right
(L/R) audio input terminals. Adjust the oscillator
to 40 Hz,1 Vrms. Listen for air leaks around the
transformer cup gasket. If there is
a“whooshing”noise,there is probably an air leak
around the gasket. Refer to the Disassembly/
Assembly Procedures section for instructions
on accessing this gasket. Re-position the
transformer cup gasket under the cup to make an
airtight seal.
NOTE: In order to perform the remaining
procedures,it is necessary to disassemble the
module to the woofer level. Leave all connections
intact to perform these tests. Remove the cover
using the procedures in the Disassembly/
Assembly Procedures section. Remove 6
screws which secure the heatsink to the module.
Remove 2 screws which secure the transformer
cup to the module. Slide out the transformer cup
and PCBs carefully. Lay the module on its side to
access the woofer more easily.
B. Using the same oscillator setting as part A.,
listen for air leaks around the woofer gasket. If
there is a "whooshing" noise around the
gasket,re-position the woofer gasket behind the
woofer to make an airtight seal.
A. Disconnect the woofer (connector J4) from the
Amplifier PCB. Set a DC power supply to 8
volts. Connect the positive supply lead to the
positive (+) woofer connection (red) and the
negative supply lead to the negative (-) woofer
connection (black). The woofer should move
outwards with the application of the supply
voltage.
10. Frequency Response of Bass Channel
NOTES: Pull the heatsink away from the
Amplifier PCB to expose the board's solder side.
It will be necessary to access the woofer output
connector (J4) to perform the remaining
procedures.
Bass amplifier output measurements are made
across J4 pins 1 and 2. The amplifier uses a
bridged output. Do not connect either output to
ground. Any test equipment that will be
connected to these points must be floated,or
isolated from ground.
A. Make up a temporary set of connections to the
woofer output connector J4.
B. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 100
Hz,200 mVrms.
8. Woofer Rub and Tick Test
A. Connect an oscillator to the module’s L/R
audio input terminals. Adjust the oscillator to 10
Hz,1.5 Vrms. No extraneous noises such as
rubbing,scraping or ticking should be heard.
NOTE: To distinguish between normal
suspension noise and rubs or ticks,displace the
cone on the woofer slightly with your fingers. If
the noise can be made to go away or get worse,it
is a rub or a tick and the woofer should be
replaced. If the noise stays the same,it is normal
suspension noise and the woofer is fine.
Suspension noises will not be heard with
program material.
C. Connect a piece of test equipment capable of
measuring decibels to the woofer output
connector J4. Make sure that the meter is not
grounded. Measure the decibels at this setting
and use as a reference for all other readings.
D. Adjust the oscillator frequency and measure
the relative response according to the chart
located at the end of this procedure (next page).
21
Frequency Relative Response
20 Hz -18.0 dB ± 2.0 dB
55 Hz +1.8 dB ± 1.5 dB
100 Hz 0 dB
200 Hz -0.5 dB ± 1.5 dB
400 Hz -10.7 dB ± 1.5 dB
11. Bass Channel Dynamic EQ Gain
NOTE: Use the same test setup as Procedure 10.
A. Adjust the oscillator to 100 Hz,30 mVrms. Use
this as a reference point.
B. Adjust the oscillator to 55 Hz. There should be
a boost of approximately 5 dB. (a 3.0 dB ± 1.0
dB difference between the 30mV and the 200 mV
input level). Refer to the chart in the previous
procedure.
C. Measure the voltage across the load. It should
be approximately 15.8 volts (50 watts). The signal
should look undistorted when viewed on an
oscilloscope.
Complete System Tests
NOTE: Use these procedures when a complete
AM-3P system (module and satellites) comes in to
be serviced.
1. System Phase Test
A. Use the procedures already listed for the
satellites and the module. Use Procedure #2
under Satellite Test Procedures and Procedure
#9 under Module Test Procedures.
2. System Sweep Test
A. Use the procedures already given for the
satellites and the module,except use 220 mVrms
for both parts of the test. Use Procedure #1 under
Satellite Test Procedures and Procedure #2
under Module Test Procedures. Make sure that
the satellites are connected to the bass module.
12. Woofer Power Output Test
NOTE: Use the same test setup as Procedure
10,except remove the dB meter. Make sure that
any test equipment connected to the woofer
output is floated (or isolated from ground).
A. Connect a 5Ω resistive load to the woofer
output. Connect a voltmeter across the load.
NOTE: These measurements can be obtained at
120 and 240 V. Results will vary depending on the
line voltage used.
B. Connect an oscillator to the module’s L/R audio
input terminals. Adjust the oscillator to 100 Hz,345
mVrms.
3. All Other Tests
A. All other tests listed under Module Test
Procedures can be used to test a complete
system.
22
PARTS LISTS AND EXPLODED VIEWS
The following section contains parts lists and exploded views for the AM-3P powered
speaker system. The parts lists are broken down as follows:
- Module Parts List and Module Exploded View. A view of the woofer is contained in
a separate figure.
-Satellite Parts List and SatelliteExploded View.
-Packaging Parts List and Packaging Exploded View.
-PCB Assembly Parts Lists. PCB layouts and schematics are located in the back of
the service manual.
23
AM-3P Bass Module Parts List (Figures 5 and 6)
Item
Number
Description Part Number Qty.
Per
Module
1 Cap-Cover,White 145105-1 1
Cap-Cover,Black 145105-2 1
2 Screw-Mach.,8-32x1/2,PAN,XREC 121316-08 1
3 Cover-White,International 144590-0231 1
Cover-Black,International 144590-0222 1
Cover-Black,Japan 144590-0822 1
4 Knob-Control,White 148839-1 3
Knob-Control,Black 148839-2 3
5 PCB Assy-EQ,US/International 193567-1 1,2
PCB Assy-EQ,Japan 143624-2 1 1,2
PCB Assy-EQ,Europe 143624-3 replaced by 175302-3 1 1,2
6 Screw-HILO,6x1/2,PAN,XREC 127015-08 1
7 Gasket-Cover,Connector 146208 1
See Note
8 Bracket-Adapter,Black 144587-2 1 1
9 Heat Sink 144588 1 1
10 Screw-HIRS,8-10x1,PAN,XREC/SQ 137527-16 8
11 PCB Assy-Amplifier 149374 1 1,2
PCB Assy-Amplifier 143627 1 1,2,3
12 Foam Tape-3"
129284-030
11
13 Cable-Flat,16 pin,Terminated 144437 1
14 Clip-Spring,Transistor 144591 2
15 Screw-Shoulder,#8-32x.31L 143444-04 4
16 Washer-Flat,#10,.08-.085 THK 146981 4
17 Grommet-Vibration Isolator 143445 4
NOTES
1. This part is not normally stocked as a service part.
2. Refer to either the EQ or Amplifier PCB Assembly Parts
Lists for the part numbers of components located on these
boards.
3. This version of the Amplifier PCB has been replaced by
P/N 149374. Refer to the Amplifier PCB Assembly Parts List
and Schematic for specific information.
24
AM-3P Module Parts List (Continued)
Item
Number
Description Part Number Qty.
18 Transformer -120/240V (US/Eur.) 143051 1
Transformer -100V (Japan) 145318 1
19 Cup-Transformer,Black 144589-2 1
20 Gasket-Transformer Cup 143514 1
21 Woofer -5-1/4" 143357 1
22 Screw-HIRS,8-10x3/4,PAN,XRC/SQ 137527-12 4
23 Woofer Gasket 104794-08 1
24 Cable-Speaker,Safety Controlled 143513 1
AM-3P Satellite Parts List (Figure 7)
Item
Number
Description Part Number Qty.
1 Grille Assembly-Left,Black 142142-11 1
Grille Assembly-Left,White 142142-13 1
See Note
Per
Module
See Note
Per
Satellite
Grille Assembly-Right,Black 142142-21 1
Grille Assembly-Right,White 142142-23 1
2 Grille Frame-Left,Black 142079-11 1
Grille Frame-Left,White 142079-13 1
Grille Frame-Right,Black 142079-21 1
Grille Frame-Right,White 142079-23 1
3 Twiddler,2-1/4" (Gasket-Backed) 147525 1
4 Screw-HIRS,6-10x1/2,PAN,XREC 124773-08 6
5 Batting-Polyester 116082 N/A 1
6 Connector,Terminal Strip 136547 1
7 Terminal Cover-Left,Black 136546-11 1
Terminal Cover-Left,White 136546-13 1
Terminal Cover-Right,Black 136546-21 1
Terminal Cover-Right,White 136546-23 1
NOTE
1. This part is not normally stocked as a service part.
25
FIGURE 6
Figure 5. AM-3P Bass Module Exploded View
26
VIEW A
Figure 6. Woofer Location in Module
Figure 7. AM-3P Satellite Exploded View
27
AM-3P Packaging Parts List (Figure 8)
Item
Number
Description Part Number Qty.
Per
Carton
1 Polybag (Satellite Parts) 144677 2
2 Packing-Insert,EPS 136436 2
3 Literature Kit (N.America) 143516-1 1 1
Literature Kit (Europe) 143516-2 1 1
Literature Kit (UK) 143516-4 1 1
Literature Kit (Australia) 143516-5 1 1
Literature Kit (International) 143516-6 1 1
which consists of:
Polybag 103351 1
Owner's Manual 143515 1
Card-Warranty,Universal 149225 1
Warranty Service List 122766 1
(N.America)
See Note
All Products Brochure 141478 1
(N.America)
Envelope (N.America,International ) 123001 1
Envelope (Europe,Japan,UK, Aus.) 128450 1 1
Adaptor-120/230V,Polarized 147013 1
(International)
Sheet-Instruction (International) 147751 1
Sheet-Instruction 149523 1 1
4 Packing-Insert,EPS 143518 2
5 Packing-Insert,EPS 143517 1
6 Polybag (Bass Module) 106595 1
7 Cable-Audio Input 143630 1
8 Cable-Interconnect,White,20' 140236 2
Cable-Interconnect,Black,20' 130915 2
(Japan)
NOTE
1. Product sold in Japan does not contain a literature kit. However,an envelope and instruction
sheet are included in the carton.
28
AM-3P Packaging Parts List (Continued)
Item
Number
Description Part Number Qty.
9 Line Cord-120V,Detachable 146999 1
(N.America,International)
Line Cord-Euro,Detachable 148203 1
(Europe)
Line Cord-100V,Detachable 145316 1
(Japan)
Line Cord-230V UK,Detachable 134725 1
(UK)
Line Cord-230V Aus.,Detachable 134726 1
(Australia)
10 Carton-Generic 149086 1
Carton-Japan 145757 1
See Note
Per
Carton
Figure 8. AM-3P Packaging Exploded View
29
AM-3P EQ PCB Assembly Parts List
Resistors
Description
Reference
Designator
R1,4,29,39,41,4345,46,52,59,60,
10kΩ,5%,1/8W,
Chip
107,120,132,207,
220,229,232
R2,3,5,33,34,38,
57,149,249
100kΩ,5%,1/8W,
Chip
R6,48,56,62 1MΩ,5%,1/8W,
Chip
R7,8,36,42,47,
55,58,68,129
20kΩ,5%,1/8W,
Chip
R9,37,49,66,67 2kΩ,5%,1/8W,
Chip
R10 27.4kΩ,1%,1/8W,
Chip
R11,15,32 6.81kΩ,1%,1/8W,
Chip
R12,112,212 8.25kΩ,1%,1/8W,
Chip
R13,24,69 5.11kΩ,1%,1/8W,
Chip
R14,121,221 10Ω,5%,1/8W,
Chip
R16,18,35,50,51,
101-104,115,
1kΩ,5%,1/8W,
Chip
201-204,215
R17,28,108,130,
208,230
330Ω,5%,1/8W,
Chip
R19,21,114,214 51.1kΩ,1%,1/8W,
Chip
R20,119,219 2kΩ,1%,1/8W,
Chip
R22 10kΩ,2%,1/4W,
52mm,Carbon
Film
R25 18.2kΩ,1%,1/8W,
Chip
R26,27,113,213 24.3kΩ,1%,1/8W,
Chip
R30,53 91Ω,5%,1/8W,
Chip
R31,61,125,225 14.3kΩ,1%,1/8W,
Chip
R40 75kΩ,1%,1/8W,
Chip
Part Number See Note
124895-1035
124895-1045
124895-1055
124895-2035
124895-2025
124894-2742
124894-6811
124894-8251
124894-5111
124895-1005
124895-1025
124895-3315
124894-5112
124894-2001
121243-1211032
124894-1822
124894-2432
124895-9105
124894-1432
124894-7502
30
Resistors (Continued)
Reference
Description Part Number See Note
Designator
R54 162Ω,1%,1/8W,
Chip
R105,106,205,206 3.9kΩ,5%,1/8W,
Chip
R109,209 681Ω,1%,1/8W,
Chip
R110,210 6.19kΩ,1%,1/8W,
Chip
R111,127,128,
211,227,228
12.1kΩ,1%,1/8W,
Chip
R116,216 20kΩ,1%,1/8W,
Chip
R117,217 6.81kΩ,1%,1/8W,
Chip
R118,218 30.1kΩ,1%,1/8W,
Chip
R122,124,222,224 100kΩ,1%,1/8W,
Chip
R123,223 1kΩ,1%,1/8W,
Chip
R126,226 953Ω,1%,1/8W,
Chip
R131,231 1Ω,5%,1/4W,
52 mm,Carbon
Film
R133,233 1kΩ,2%,1/4W,
52 mm,Carbon
Film
124894-1620
124895-3925
124894-6810
124894-6191
124894-1212
124894-2002
124894-6811
124894-3012
124894-1003
124894-1001
124894-9530
121243-1211R05
121243-1211022
Diodes
Reference
Description Part Number See Note
Designator
D1-10,D12-15,
D17-19,101-104,
1N4148,52mm,
Axial
121501
108,201-204,208
Transistors
Reference
Description Part Number See Note
Designator
Q1,5,7-9,11 NPN,Tape 117921
Q2-4,6,10,12 PNP,Small 119168
31
Capacitors
Reference
Description Part Number See Note
Designator
C1-4,28,30,32,35,
10µF,20%,EL
137126-100
36,101,102,126,
201,202,226
C6,7,9,10,13,14 .47µF,5%,Box
137127-474
Film
C8,120-124,
220-224
C11,103,105,111,
33000pF,20%,
Chip
100pF,5%,Chip
124958-3331
124956-1012
115,203,205,211,
215
C12,29,34,104,
47µF,20%,EL 137126-470
204
C15,113,114,213,
214
C16,106,109,110,
.12µF,5%,Box
137127-124
Film
.0082µF,5%,Film 137123-822
206,209,210
C17 33µF,20%,EL,
147522-330
Bi-polar
C31,116,117,216,
.1µF,5%,Film 137123-104
217
C107,108,207,208 .082µF,5%,Film 137123-823
C118,218 .001µF,5%,Film 137123-102
C119,219 470pF,10%,
137269-471
Ceramic
C125,127,225,227 .0033µF,10%,Chip 124957-332
ICs
Reference
Description Part Number See Note
Designator
U2,3,5,6,101-105 Op Amp 108568
U4 CA3080 119834
U1 Quad,Transistor
145317
Array NPN
Switches
Reference
Description Part Number See Note
Designator
None Power Switch 143629
S2 DPDT,Voltage
145307 3
Select
32
Reference
Description Part Number See Note
Designator
None AC Power
Connector
J5 Connector-
Header,5 pin,
Hi Current
J7 Connector-Dual
Stereo,Mini
J8 Connector-Quad
Phono
J9 Connector-Quad
Speaker Terminal
J10 AC Jack
Connector
Connectors
146563 1
145315-5
145310
145309
145308
145306 2
Potentiometers
Reference
Description Part Number See Note
Designator
VR1 Dual 10K-Volume 145311
VR2 Dual 10K,Detent-
145312
Treble
VR3 Single 10K-Bass 145313
Fuses
Reference
Description Part Number See Note
Designator
None Connector,Fuse
140347
Clip
!
Fuse-Slo-Blo,
1.5A,5x20mm
143668-1500 4
F1
Cable Assemblies
Reference
Description Part Number See Note
Designator
S1A,S1B Cable Assy-Quick
Disconnect
145314
33
Miscellaneous
Reference
Description Part Number See Note
Designator
W1-15 Chip Jumper 124896
NOTES
1. This part is used on the -1 and -2 PCBs only.
2. This part is used on the -3 PCB only.
3. This part is used on the -1 and -3 PCBs only.
4. This part is critical for safety purposes. Failure to use a substitute replacement with the
same safety characteristics as the recommended replacement part might create shock,fire
and/or other hazards.
34
AM-3P Amplifier PCB Assembly Parts List
Resistors
Reference
Description Part Number See Note
Designator
R30,31 5.1Ω,5%,1/4W,
52 mm,Carbon
Film
R32,33,131,142,
231,242,303,313,
10kΩ,5%,1/8W,
Chip
403,413
R34,138,238,308 1kΩ,5%,1/8W,
Chip
R130,141,230,
241,302,312,318,
100kΩ,5%,1/8W,
Chip
402,412,418
!
51Ω,5%,1/4W,
Fusing
R132,143,232,
243,304,314,404,
414
!
5.1Ω,5%,1/4W,
Fusing
R134,145,234,
245,306,316,406,
416
R135,139,140,
235,239,240,301,
220Ω,5%,1/8W,
Chip
307,310,311,407,
410,411
R136,236 20kΩ,5%,1/8W,
Chip
R137,237,309 5.11kΩ,1%,1/8W,
Chip
R144,244,317,417 10Ω,5%,1/8W,
Chip
R146,246 0.1Ω,10%,2W,
Cut,Axial
R147,247 3.3kΩ,5%,1/8W,
Chip
R408 3.3kΩ,5%,1/10W,
0805,Chip
R409 20kΩ,5%,1/10W,
0805,Chip
121243-1215R15
124895-1035
124895-1025
124895-1045
130102-510 1
130102-5R1 1
124895-2215
124895-2035
124894-5111
124895-1005
146759
124895-3325
133626-3325
133626-2035
Reference
Designator
D105-107,
205-207,301,302,
401,402
Diodes
Description Part Number See Note
1N4148,52mm,
121501
Axial
35
Capacitors
Reference
Description Part Number See Note
Designator
C17,125,225 10µF,20%,EL 137126-100
C18,120-123,126,
.0047µF,5%,Chip
131754-472
220-223,226,
301-304,401-404
C20,24 560µF,20%,EL 128548
C21,25 10000µF,35V,
143623
105C,EL
C22,23,26,27,124,
224,305,405
Reference
33000pF,20%,
124958-3331
Chip
Transistors
Description Part Number See Note
Designator
Q1,102,103,110,
NPN,Tape
117921
202,203,210,302,
303,310,402,403,
410
Q101,104,109,
PNP,Small
119168
201,204,209,301,
304,401,404
Q105,205,305,405 PNP,2SB560F 140349
Q106,206,306,406 NPN,2SD438F 140348
Q107,207,307,407 NPN,Formed 129001
Q108,208,308,408 PNP,Formed 129002
ICs
Reference
Description Part Number See Note
Designator
U1 Voltage Regulator,
146234
TO-92,+8V
U2 Voltage Regulator,
146235
TO-92,-8V
U106,206,301,401 Single Op Amp 250475-001
36
Connectors and Jumpers
Reference
Description Part Number See Note
Designator
J1 Connector-
133220-05
Header,5 pole,
Med.Current
J2 Connector-
145305-15
Header,Rt.Angle,
15 pin
J4 Connector-
133220-02
Header,2 pole,
Med.Current,.156
W1,4,12,34,35,47 Jumper-Chip,0805 133627 2
W2,3,5-11,14-27,
Jumper-Chip
124896 2
29-33,36-42,45,
46,48,49
W1,3-46 Jumper-Chip 124896 3
Relays and Rectifiers
Reference
Description Part Number See Note
Designator
K1 Relay-DPST,TV-3
143622
rated
Z1 Rectifier-Bridge,
112027
Cut
Z2 Rectifier-Bridge,
148950
Formed
NOTES
1. This part is critical for safety purposes. Failure to use a substitute replacement with the
same safety characteristics as the recommended replacement part might create
shock,fire,and/or other hazards.
2. These jumpers are used on the latest version of the Amplifier PCB,P/N 149374.
3. These jumpers are used on the original version of the Amplifier PCB,P/N 143627.
37
NOTES FOR FUTURE REFERENCE
38
SCHEMATICS AND PCB LAYOUTS
Two schematics are enclosed backed by their respective PCB layouts. The following PCB
assemblies are contained here:
.EQ PCB schematic backed by component side and solder side PCB layouts
.Amplifier PCB schematic backed by component side and solder side PCB layouts
39
NOTES FOR FUTURE REFERENCE
40
SPECIFICATIONS AND FEATURES SUBJECT TO CHANGE WITHOUT NOTICE
12/92: REV.0
Bose Corporation
The Mountain
Framingham, Massachusetts USA 01701
P/N 149821
FOR TECHNICAL ASSISTANCE OR PARTS ORDERING,CALL 800-367-4008
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