Sony MDR-NC300D, Service Manual

Page: 7 / 24

MDR-NC300D
MDR-NC300D
7 7
2-6. MAIN BOARD
Note : When replacing the headphone assy, please refer to “NOTE THE MAIN BOARD, SUB BOARD OR HEADPHONE ASSY REPLACING”
of service note (see page 2).
1
Remove solder of
battery (–) terminal.
5 MAIN board
3 Remove solder of
battery (+) terminal.
4
battery (+) terminal
2 battery (–) terminal
SECTION 3
TEST MODE
SECTION 4
ELECTRICAL ADJUSTMENT
SETTING THE TEST MODE
Procedure:
1. Slide the [POWER] switch to turn the power on (At this time,
[HOLD] is off).
2. Slide the [HOLD] switch to HOLD on.
3. Press the button as following order.
Note 1:
Press the button as it is continuously though “HOLD” is displayed
on the liquid crystal display whenever the button is pressed.
[NC OPTIMIZE]
→
[]
→
[VOLUME –]
→
[MONITOR]
→
[SOUND MODE]
→
[]
→
[VOLUME –]
→
[MONITOR]
→
[SOUND MODE]
→
[NC OPTIMIZE]
4. After the message “TestMode” is displayed on the liquid crys-
tal display for two seconds, the test command selection menu
is displayed.
Note 2: Turn off [HOLD] and execute the operation from procedure 2
again when “TestMode” is not displayed on liquid crystal display,
or it makes a mistake in the operation on the way.
OPERATING THE TEST MODE
Procedure:
1. Press the [] or [VOLUME –] button to select the
test command.
• Test command list
Command name Content
NC Adjust
The NC gain is adjusted. Refer to “SEC-
TION 4 ELECTRICAL ADJUSTMENT”.
Debug
Never execute this mode. The setting
value is destroyed.
FW Ver The fi rmware version is displayed.
Ext Control
Never execute this mode. Not used for the
servicing.
2. Press the [SOUND MODE] button, and execute the selected
test command.
3. The test command is ended when the [MONITOR] button is
pressed while executing the test command and it returns to the
menu.
4. Press the [MONITOR] button with the test command selection
menu displayed to end the test mode.
FACTORY SHIPMENT MODE
Execute this mode when returning the set to the customers.
Procedure:
1. While pressing the [NC OPTIMIZE] button, slide the [POW-
ER] switch to turn the power on.
2. It is con fi rmed that “ALL RESET” was displayed on the liquid
crystal display, and release the [NC OPTIMIZE] button.
3. It is con fi rmed that “ALL RESET” disappeared from the liq-
uid crystal display, and pull out the battery without turning off
power.
NOISE CANCEL VOLUME ADJUSTMENT
Connection:
+
–
amplifier
speaker
AF oscillator
Procedure:
1. Generate a sine wave of speci fi c frequency (250 Hz) from a AF
oscillator, and output it from a speaker placed at the forward
position.
2. Wear this headphones on the ear, and slide the [POWER]
switch to turn the power on.
3. Slide the [HOLD] switch to HOLD on.
4. Press the button as following order.
[NC
OPTIMIZE]
→
[]
→
[VOLUME –]
→
[MONITOR]
→
[SOUND MODE]
→
[]
→
[VOLUME –]
→
[MONITOR]
→
[SOUND MODE]
→
[NC OPTIMIZE]
5. After the message “TestMode” is displayed on the liquid crys-
tal display for two seconds, the test command selection menu
is displayed.
6. Press the [] or [VOLUME –] button to select the
“NC Adjust”, and press the [SOUND MODE] button.
7. The screen for the adjustment is displayed (Refer to the fi gure
below).
8. With this headphones worn, adjust the gain at the position that
decreases the sound from the speaker on the audibility most
and hears.
[SOUND MODE] button :
L-ch/R-ch/L+R-ch changes whenever the button is pressed.
[]/[VOLUME –] buttons:
The gain value changes whenever the button is pressed.
Note: When the headphones are not covered with the ear pieces complete-
ly, the adjustment may not be performed correctly.
Make sure that the ear pieces cover the headphone completely.
9. Press the [MONITOR] button to release the “NC Adjust”
mode.
10. Press the [MONITOR] button to release the test mode.
11. Slide the [POWER] switch to turn the power off, execute
“FACTORY SHIPMENT MODE” in test mode.