SERVICE MANUAL
NOISE CANCELING
HEADPHONES
US Model
Canadian Model
AEP Model
UK Model
E Model
Tourist Model
SPECIFICATIONS
MDR-NC50
Ver. 1.2 2005.02
9-879-314-03
2005B05-1
© 2005.02
Sony Corporation
Personal Audio Group
Published by Sony Engineering Corporation
Note on chip component replacement
· Never reuse a disconnected chip componet
· Notice that the minus side of a teamtalum capacitor may be damaged by
heat
General
Type
Dynamic, closed
Driver units
40 mm, dome type
Power handling capacity
100 mW
Impedance
40
at 1 kHz (when the power is on)
100
at 1 kHz (when the power is off)
Sensitivity
102 dB/mW (when the power is on)
100 dB/mW (when the power is off)
Frequency response
14
- 22,000 Hz
Frequency range of active noise attenuation
40
- 1,500 Hz, more than 14 dB at 300 Hz
Power source
DC 1.5 V, 1
× R03 (size AAA) battery
Mass
Approx. 290 g (11 oz) including battery
Supplied accessories
Connecting cord (0.5 m, gold-plated stereo mini plug (1) (Tourist only),
1.5 m, gold plated L type stereo mini plug (1)), R03 (size AAA) dry
battery (1) (Tourist only), Carrying case (1), Plug adaptor for in-flight
use* (single/dual) (1), Gold-plated unimatch plug adaptor (stereo phone
plug y stereo mini jack) (1), Operating Instructions (1)
* May not be compatible with some in-flight music services.
Design and specifications are subject to change without notice.
Battery
Sony alkaline LR03/AM-4 (N)
(size AAA) battery
Sony manganese R03/ UM-4
(NU) (size AAA) battery
Approx. hours*1
30 hours*2
15 hours*2
Battery life
*1 1 kHz, 1 mW + 1 mW input
*2 Time stated above may vary, depending on the temperature or conditions of use.
When to replace the battery
Replace the battery with a new one when the POWER indicator dims.
The noise canceling feature may not work correctly if battery power is low.
UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
· Unleaded solder melts at a temperature about 40 °C higher
than ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350 °C.
Caution: The printed pattern (copper foil) may peel away if
the heated tip is applied for too long, so be careful!
· Strong viscosity
Unleaded solder is more viscou-s (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
· Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
2
MDR-NC50
TABLE OF CONTENTS
1.
GENERAL ................................................................... 3
2.
DISASSEMBLY
2-1.
Disassembly Flow ...........................................................
4
2-2.
ML Board ........................................................................
4
2-3.
MR Board ........................................................................
5
2-4.
Ornamental Cap (L)/(R) ..................................................
5
2-5.
Position of lead Wires ......................................................
6
2-6.
L/R Transition Cord Location .........................................
6
2-7.
Position Of Lead Wires
At Front Plate (L)/(R) Sub Assy ......................................
7
3.
ELECTRICAL ADJUSTMENT ............................. 8
4.
DIAGRAMS ................................................................. 9
4-1.
Block Diagram ................................................................ 11
4-2.
Printed Wiring Board L-CH Board ........................... 12
4-3.
Printed Wiring Boards R-CH Board .......................... 13
4-4.
Schematic Diagram ......................................................... 14
5.
EXPLODED VIEWS
5-1.
Overall Section ................................................................ 15
5-2.
Housing (L) Section ........................................................ 16
5-3.
Housing (R) Section ........................................................ 17
6.
ELECTRICAL PARTS LIST ................................ 18
3
MDR-NC50
SECTION 1
GENERAL
Features
Installing a battery
1 Open the right housing, as illustrated.
2 Open the lid of the battery box of the
headphone to insert one size AAA battery.
3 Close the lid.
Match the e on
the battery to the
e in the battery
case.
L
R
Listening to music
1 Connect the headphones to the AV
equipment.
* "WALKMAN" is a registered trademark of Sony
Corporation to represent Headphone Stereo products.
2 Turn on the power on the right side of the
headphones.
The POWER indicator lights in red. When the
power is turned on, ambient noise is reduced,
and you can listen to music more clearly at a
lower volume.
When connecting to the stereo mini jack of the remote
control's jack supplied with a WALKMAN*, etc
WALKMAN*, etc
Remote control
Connecting cord
0.5 m (supplied)
When connecting to the
stereo mini plug of a
WALKMAN*, etc
Headphones
L
R
ON
OFF
Connecting cord
1.5 m (supplied)
Noise canceling microphone
RL
for dual jacks
for stereo mini jacks
3 Put on the headphones so that the ear pads
cover your ears.
4 Turn on the power of the AV equipment.
Hearing environmental sound for safety.
Playback is muted while the MONITOR switch is
pushed so you can hear the surrounding
environment.
Note
The environmental sound might not be heard if the
microphone is covered with your fingers.
Notes on using on the
airplane
· The supplied plug adaptor can be connected to dual
and stereo mini jacks.
· Do not use the headphones when use of electronic
equipment is prohibited or when use of personal
headphones for in-flight music services is prohibited.
If you have any questions or problems concerning the
system that are not covered in this manual, please consult
the nearest Sony dealer.
L
R
monitor microphone
MONITOR
switch
(Except Tourist)
(Tourist only)
L
R
When connecting to the stereo
mini jack of the remote control's
jack supplied with a WALKMAN*,
etc.
Remote control
When connecting to the
stereo mini jack of a
WALKMAN*, etc.
Connecting cord
1.5 m (supplied)
Headphones
To headphone jack on
airplane seats
Plug adaptor (supplied)
When connecting to dual
or stereo mini jacks of
in-flight music services.
Note
· Insert the plug in the jack until you hear a click.
· To disconnect the cord, pull it out by the plug, not the
cord, as the inner conductors may break.
· Noise cancelling headphones reduce ambient
noise, and provide a quieter environment to
enhance audio entertainment.
Ambient sound is synthesized with an anti-
sound signal produced by the noise cancelling
circuit, and reduced. (Over 14 dB is reduced at
300 Hz.)
· Slim, folding design for easy portability.
· Neodymium magnets for powerful sound.
· Passive operation when noise-canceling circuit
is not activated.
· Built-in monitor function to hear surrounding
sound without taking off the headphones.
· Supplied plug adaptor for easy connectivity to
stereo or dual jack of in-flight music services.
This section is extracted from
instruction manual.
Ver. 1.1
4
MDR-NC50
SECTION 2
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
2-1. DISASSEMBLY FLOW
SET
2-2. ML BOARD
(Page 4)
2-4. ORNAMENTAL CAP (L)/(R)
(Page 5)
2-4. ORNAMENTAL CAP (L)/(R)
(Page 5)
2-3. MR BOARD
(Page 5)
Note: Follow the disassembly procedure in the numerical order given.
2-2. ML BOARD
qd
Remove thirteen solders.
2
two screws
(B2.6)
1
screen
3
two screws
(B2.6)
4
front plate (L)
assy
5
packing housing
qg
ML board
0
claw
qa
claw
9
Remove the ring (L) block
in the direction of arrow.
qs
button monitor
6
three screws
(B2.6)
7
sheet (housing)
8
claw
qf
claw
5
MDR-NC50
2-3. MR BOARD
8
ring (R) block
qa
MR board
6
two screws
(B2.6)
5
packing housing
3
two screws
(B2.6)
1
screen
2
two screws
(B2.6)
4
front plate (R)
assy
7
screw
(B2.6)
q;
two claws
9
Remove thirteen solders.
2-4. ORNAMENTAL CAP (L)/(R)
3
ornamental cap (R)
Take care not to break the claw when mounting or demounting the ornamental cap (L)/(R).
3
ornamental cap (L)
1
claw
1
claw
2
ring (R)
2
ring (L)
1
claw
1
claw
1
claw
1
claw