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­ 1 ­
SERVICE MANUAL
POWERED MONITOR SPEAKER
MICROFILM
SPECIFICATION
US Model
Canadian Model
AEP Model
UK Model
SMS-2P
Speaker system
2 way bass reflex
Speaker unit
Woofer : 16 cm (6 5/16 inches) dia. cone type
Tweeter: 2.5 cm (1 inch) dia. dome type
Nominal Impedance
Woofer : 6 ohms
Tweeter: 6 ohms
Power handling capacity
Woofer : 50 W
Tweeter: 40 W
Sensitivity
107 dB/W/m
Frequency range
48 Hz - 20 kHz (
±3 dB)
Dimensions
Approx. 239
× 410 × 331 mm (w/h/d)
(9 7/16
× 16 1/8 × 13 1/16 inches)
excluding projecting parts and controls
Approx. 239
× 410 × 365 mm (w/h/d)
(9 7/16
× 16 1/8 × 14 3/8 inches)
including projecting parts and controls
Enclosure volume
Approx. 14 liters
Mass
Approx. 13 Kg (28 lb 10 oz)
excluding protective cover
Power requirements
North American models
: 120 V AC, 60 Hz
European models
: 220 - 230 V AC, 50/60 Hz
Power consumption
: 44 W
Inputs
CH 1
Phono jack
× 1
Phone jack
× 1
XLR jack
× 1
CH 2
Phono jack
× 1
Phone jack
× 1
XLR jack
× 1
OTHER
RETURN jack
× 1
Input level
Phono jack
: ­10 dBm (+10 dBm)
Phone jack
: ­10 dBm (+10 dBm)
Balanced terminal : +4 dBm (+24 dBm)
RETURN
: 0 dBm (+20 dBm)
Input impedance
Phono jack
: 10 kilohms
Phone jack
: 10 kilohms
Balanced terminal : 600 ohms
Output level
SEND jack
: (0 dBm)
CASCADE jack
: (as same as RETURN level)
Tone controls
BASS 100 Hz
:
±6 dB
TREBLE 10 kHz :
±6 dB
Tweeter level controls
+2.5 dB / ­3.5 dB
Supplied accessories
Power cord (1)
Protective cover (1)
Slip stoppers (4)
Instruction manual (1)
Design and specifications are subject to change without notice.


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­ 2 ­
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, "metallized" knobs,
screws, and all other exposed metal parts for AC leakage.
Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers' instructions to use these
instruments.
2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The "limit" indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are suit-
able. (See Fig. A)
1.5 k
0.15
µF
AC
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
TABLE OF CONTENTS
1. GENERAL .................................................................... 3
2. DISASSEMBLY .......................................................... 5
3. DIAGRAMS
3-1. Circuit Boards Location ................................................... 6
3-2. Printed Wiring Board ....................................................... 7
3-3. Schematic Diagram ........................................................ 11
3-4. IC Block Diagrams ........................................................ 14
4. EXPLODED VIEWS ................................................ 15
5. ELECTRICAL PARTS LIST ................................. 17
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE
! SUR
LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES
PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE
FONCTIONNEMENT. NE REMPLACER CES COMPOSANTS
QUE PAR DES PIÈCES SONY DONT LES NUMÉROS
SONT DONNÉS DANS CE MANUEL OU DANS LES
SUPPLÉMENTS PUBLIÉS PAR SONY.
SAFETY-RELATED COMPONENT WARNING !!
COMPONENTS IDENTIFIED BY MARK
! OR DOTTED
LINE WITH MARK
!ONTHE SCHEMATIC DIAGRAMS AND
INTHE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS
WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS
MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.
Fig.A. Using an AC voltmeter to check AC leakage.


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­ 3 ­
SECTION 1
GENERAL
Features
· Professional quality inputs with high handling capacity (Balanced terminal +24 dB, phone and phono terminals +10 dB).
· Allows mixing of two different input sources.
· Magnetically shielded design allows placement near display monitors, TVs, etc.
· 2 way speaker and wood cabinet designed for high fidelity.
· Use of sandwich construction in baffle board damping.
· Up to 20 of these speakers can be connected via cascade connections.
1 SEND terminal
Outputs a mix of the sounds input to channel 1 and channel 2. Connect to an
effector or recording device (etc.). The sound is output as adjusted by the BASS
and TREBLE.
2 TW LEVEL control
Adjusts the output level of the tweeter.
Turn toward the right to increase. Turn toward the left to decrease.
3 MASTER VOL. (volume) control
Turning to the right increases the level of the sound output from the speaker.
4 BASS control
Turn to the right to increase the level of the bass. Turn to the left to decrease the
level of the bass. (Increasing the level of the bass when listening at high vol-
umes may cause the sound to distort.)
5 TREBLE control
Turn to the right to increase the level of the treble. Turn to the left to decrease
the level of the treble.
6 CH 1 IN (channel 1 input)
See next page for details.
7 CH 2 IN (channel 2 input)
See next page for details.
8 Rear panel guards
Protect the controls on the rear of the speaker. Located on the left and right.
9 POWER switch
Turns the power to the speaker ON/OFF. (Before turning the power ON, be sure
the MASTER VOL. control is set to the "0" position.)
10 AC socket
Connect to a wall outlet (120 V in U.S.A. or Canada, 220-230 V in Europe)
using the supplied power cord.
11 BREAKER
Press if the pilot lamp on the front panel does not light when the power is turned
on. This resets the power supply so you can use the speaker.
12 RETURN terminal
Use to input an external sound source directly to the speaker's power amp. Use
this terminal to input sound output to an effector, or when connecting several
speakers.
13 CASCADE OUT terminal
Allows you to output a mix of the sounds input to channel 1 and channel 2. Use
to output sound when connecting several speakers.
14 Power indicator
Lights when the POWER switch is set to the ON position.
1
2
3
4
5
6
7
8
9
10
11
12
13
Names and Functions of Parts
Rear
14
Front
This section is extracted from
instruction manual.


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­ 4 ­
23
1
2
3
1
1:GND
2:HOT
3:COLD
1:GND
2:COLD
3:HOT
1 INPUT VOL. (channel 1 input level) control
Turning to the right increases the level of the sound output from the channel 1.
2 Pin plug input terminal
Phono plug input terminal for channel 1. Connect to the output on a piece of audio
equipment (etc.).
3 Standard plug input terminal
Phone plug input terminal for channel 1. Connect to the output on a musical in-
strument (etc.).
4 Balanced input terminal
Balanced input terminal for channel 1. Connect to the output terminal of a profes-
sional mixing console (etc.).
5 Balanced input terminal polarity switch
Use to switch the polarity of the channel 1 balanced input terminal.
1 INPUT VOLUME. (channel 2 input level) control
2 Pin plug input terminal
3 Standard plug input terminal
4 DIRECT switch. (Only for Balanced input terminal)
Setting this switch to DIRECT allows you to bypass the tone controls and send the
sound from a mixer (etc.) directly to the speaker's power amplifier. In this case,
BASS and TREBLE adjustments are not possible. Only the MASTER VOL. and
TW LEVEL can be adjusted.
Note
When the DIRECT switch is set to DIRECT, no sound will be output to the other
speakers (if other speakers are connected).
5 Balanced input terminal
6 Balanced input terminal polarity switch
CH 1 INPUT
12
3
4
5
CH 2 INPUT
12
3
4
5
6
Speaker Connections and Placement
Placement
The speaker can be placed vertically or horizontally.
Connections
Be sure to set the POWER switch on the back panel to OFF before making any connections.
Connect only one.
Balanced (XLR) cord
phone plug cord
Audio phono cord
Balanced terminal polarity
When the balanced input
terminal polarity switch is
set to 2HOT.
When the balanced input
terminal polarity switch is
set to 3HOT.
To the output terminals of an electronic instrument,
mixing console, computer, or audio device (etc.).
To a wall outlet


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­ 5 ­
SECTION 2
DISASSEMBLY
PLATE, REAR-1
1eight screws
(+P 4X8)
2connector
3CN11
4CN7
1CN2 board
2CN1 board
3two screws
(+BV 3X14)
4screw
(+BV 3X6)
9 two screws (+BV 3X8)
6four screws
(+BV 3X6)
7shield (A)
PLATE, REAR-2
5 two screws (+BV 3X12)
8 POWER AMP board
!º CONTROL board
!TM INPUT1 board
!¢ INPUT2 board
!§ POWER board
!¡ four screws (+BV 3X8)
!£ four screws (+BV 3X8)
! two screws (+BV 3X8)