STR-SE381
US Model
SERVICE MANUAL
FM STEREO/FM-AM RECEIVER
MICROFILM
Manufactured under license from Dolby Laboratories
Licensing Corporation.
"Dolby" "Pro Logic" and the double-D symbol
a are
trademarks of Dolby Laboratories Licensing
Corporation.
SPECIFICATIONS
-- Continued on next page --
Audio power specifications
POWER OUTPUT AND TOTAL HARMONIC DISTORTION
With 8-ohm load, both channels driven, from 40 - 20,000 Hz,
rated 60 watts per channel minimum RMS power, with no more
than 0.5% total harmonic distortion from 250 milliwatts to
rated output.
Amplifier section
Stereo mode
(8 ohms at 40 Hz - 20 kHz less than 0.5% total
harmonic distortion)
60 W + 60 W
Surround mode
(8 ohms at 1 kHz, THD 0.5%)
Front: 60 W/ch
Center: (Pro Logic Mode)
60 W
Rear: 60 W/ch
Frequency response
PHONO: RIAA
equalization curve ±0.5 dB
TV/DBS, CD, TAPE/MD, VIDEO INPUT
10 Hz - 50 kHz ±1 dB
Inputs
Sensitivity
Impedance
S/N (weighting network,
input level)
PHONO
(MM)
2.5 mV
50 Kilohms
72 dB*
(A, 2.5 mV)
CD
400 mV
TAPE/MD,
250 mV
TV/DBS,
50 Kilohms
82 dB*
VIDEO
(A, 150 mV)
*78 IHF
Outputs
TAPE/MD REC OUT:
Voltage: 150 mV,
Impedance: 10 kilohms
VIDEO AUDIO OUT:
Voltage: 150 mV,
Impedance: 10 kilohms
PHONES:
Accepts low and high impedance headphones
Muting
Full mute
BASS BOOST
+10 dB at 70 Hz
TONE
±8 dB at 100 Hz and 10 kHz
FM tuner section
Tuning range
87.5 - 108.0 MHz
Antenna terminals
75 ohms, unbalanced
300 ohms, balanced
Sensitivity
Mono: 18.3 dBf, 4.5
µV
Stereo: 38.3 dBf, 45
µV
Usable sensitivity
11.2 dBf, 2
µV (IHF)
S/N
Mono: 76 dB
Stereo: 70 dB
Harmonic distortion at 1 kHz
Mono: 0.3%
Stereo: 0.59%
Separation
45 dB at 1 kHz
+0.5
Frequency response
30 Hz - 15 kHz
2
dB
Selectivity
60 dB at 400 kHz
AM tuner section
Tuning range
531 - 1710 kHz
Antenna
Loop antenna
Usable sensitivity
50 dB/m (at 1,000 kHz)
S/N
54 dB (at 50 mV/m)
Harmonic distortion
0.5% (50 mV/m, 400 kHz)
Selectivity
At 10 kHz: 40 dB
-- 2 --
1.
GENERAL
Location and Function of controls ················································ 3
2.
TEST MODE ···························································· 5
3.
DIAGRAMS
3-1.
Circuit Boards Location ····················································· 6
3-2.
Printed Wiring Board (Display Section) ···························· 7
3-3.
Schematic Diagram (Display Section) ······························· 9
3-4.
Printed Wiring Board (Volume Section) ··························· 11
3-5.
Schematic Diagram (Volume Section) ····························· 13
3-6.
Printed Wiring Board (Main Section) ······························ 15
3-7.
Schematic Diagram (Main (1/3) Section) ························ 17
3-8.
Printed Wiring Board (Power Section) ····························· 19
3-9.
Schematic Diagram (Main (2/3), Power Section ) ··········· 21
3-10. Schematic Diagram (Main (3/3), SP SW Section ) ·········· 23
3-11. IC Pin Function ································································ 25
3-12. IC Block Diagrams ··························································· 27
4.
EXPLODED VIEWS
4-1.
Front Panel Section ·························································· 29
4-2.
Chassis Section ································································· 30
5.
ELECTRICAL PARTS LIST ································ 31
TABLE OF CONTENTS
General
System
Tuner section:
PLL quartz-locked digital synthesizer system
Preamplifier section:
Low-noise NF type equalizer
Power amplifier section:
Pure-complementary SEPP
Power requirements
120 V AC, 60 Hz
Power consumption
150 W
AC outlets
2 switched, total 120 W/1A Max
Dimensions
17
× 5 7/8 × 11 5/8 inches
(430
× 145 × 295 mm)
Mass (Approx.)
14 IB 5 oz (6.5 kg)
Supplied accessories
FM wire antenna (1)
AM loop antenna (1)
Remote controller (remote) (1)
Size AA (R6) batteries (2)
Design and specifications are subject to change without notice.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK
! OR DOTTED LINE WITH
MARK
! ON THE SCHEMATIC DIAGRAMS AND IN THE 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.
After correcting the original service problem, perform the
following safety checks 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
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" indication
is 0.75 V, so analog meters must have an accurate low-voltage
scale. The Simpson 250 and Sanwa SH-63Trd are examples of
a passive VOM that is suitable. Nearly all battery operated
digital multimeters that have a 2V AC range are suitable. (See
Fig. A)
SAFETY CHECK-OUT
To Exposed Metal
Parts on Set
0.15
µF
1.5k
AC
voltmeter
(0.75V)
Earth Ground
Fig. A. Using an AC voltmeter to check AC leakage.
-- 3 --
SECTION 1
GENERAL
LOCATION AND FUNCTION OF CONTROLS
[FRONT PANEL]
1
POWER switch (I/
u)
2
CENTER LEVEL +, buttons
3
REAR LEVEL +, buttons
4
PRO LOGIC indicator
5
C. STUDIO indicator
6
HALL indicator
7
VIDEO FUNCTION button
8
TV/DBS FUNCTION button
9
TAPE/MD FUNCTION button
0
MASTER VOLUME control
!¡
BALANCE control
!TM
TREBLE control
!£
BASS control
!¢
BASS BOOST button/indicator
!
SURROUND ON/OFF button
!§
MODE button
!¶
SET UP button
!·
EFFECT/DELAY TIME button
!ª
PHONO FUNCTION button
@º
TUNER FUNCTION button
@¡
CD FUNCTION button
@TM
DIRECT button
@£
SHIFT button
@¢
Numeric buttons
@
PRESET TUNING +, buttons
@§
MEMORY button
@¶
AM button
@·
FM button
@ª
FM MODE button
#º
TUNING +, buttons
#¡
PHONES jack
#TM
SPEAKERS A/B switch
12 3 45 6
7 8 9
!º
@§
@·
#º
#TM
#¡
!¡
!TM
!
!¶ !§
@º !ª
@¡
@TM
@£
@¢
@
@¶
@ª
!£
!¢
!·
-- 4 --
[REAR PANEL]
1
y SIGNAL GND
2
AC OUTLET
3
AC power cord
4
FRONT SPEAKERS (A/B)
5
SURROUND SPEAKERS (CENTER)
6
SURROUND SPEAKERS (REAR)
7
VIDEO
8
TV/DBS
9
TAPE/MD
!º
CD
!¡
PHONO
!TM
ANTENNA (AM/FM)
1
2
!¡
!º
!TM
9
5
4
3
7
6
8
STR-SE381
-- 5 --
-- 6 --
SECTION 2
TEST MODE
INITIALIZATION MODE
*
All preset contents are cleared when this mode is activated. Use
this mode before returning the product to clients upon
completion of repair.
*
Procedure:
While depressing the VIDEO, TAPE/MD and the CD buttons
simultaneously, press the power [I/
u] button to turn on the main
power. The message INITIAL appears and initialization is
performed.
FLUORESCENT INDICATOR TUBE TEST MODE
*
All fluorescent segments are tested. When this test is activated,
all segments turn on at the same time, then each segment turns
on one after another.
*
Procedure:
While depressing the CD and the TAPE/MD buttons
simultaneously, press the power [I/
u] button to turn on the main
power. All segments turn on at the same time, then each segment
turns on one after another. The message FINISH appears when
this test is complete.
AM CHANNEL STEP 9 kHz/10 kHz
SELECTION MODE
*
Either the 9 kHz step or 10 kHz step can be selected for the AM
channel step.
*
Procedure:
Set the FUNCTION to AM. Turn off the main power.
While depressing the TUNING+ button, press the power [I/
u]
button to turn on the main power. Either the message 9k STEP
or 10k STEP appears. Select the desired step.
REAR SPEAKER GAIN UP MODE
*
The rear speaker gain can be set to either NORMAL or GAIN
UP.
*
Procedure:
While depressing the -SURROUND button, press the power [I/
u] button to turn on the main power. Either the message
NORMAL or GAIN UP appears. When the product enters this
mode again, the other gain appears. Select the desired gain.
SECTION 3
DIAGRAMS
3-1.
CIRCUIT BOARDS LOCATION
· Waveforms
For schematic diagrams.
Note:
· All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
· All resistors are in
and 1/4 W or less unless otherwise
specified.
·
%
: indicates tolerance.
·
¢
: internal component.
· 2 : nonflammable resistor.
· 1 : fusible resistor.
· C : panel designation.
· U : B+ Line.
· V : B Line.
· H : adjustment for repair.
· Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
No mark : FM
· Voltages are taken with a VOM (Input impedance 10 M
).
Voltage variations may be noted due to normal production
tolerances.
· Waveforms are taken with a oscilloscope.
· Circled numbers refer to waveforms.
· Signal path.
F
: FM
THIS NOTE IS COMMON FOR PRINTED WIRING
BOARDS AND SCHEMATIC DIAGRAMS.
(In addition to this necessary note is printed in each
block.)
For printed wiring boards.
Note:
· X : parts extracted from the component side.
· b : Pattern from the side which enables seeing.
Note:
The components identified by
mark
! or dotted line with mark
! are critical for safety.
Replace only with part number
specified.
SECONDARY board
STANDBY board
MAIN board
VOLUME board
VR-TONE board
KEY board
SW (B) board
SW (A) board
DISPLAY board
SW board
PRIMARY board