Electrical Adjustment - Sony mdr-nc50 Service Manual

MDR-NC50
SECTION 3

ELECTRICAL ADJUSTMENT

NOISE CANCELING VOLUME ADJUSTMENT
Preparation:
AF oscillator
sine wave 250 Hz
Procedure:
1. Generate a sine wave of specific frequency (250 Hz) from a
AF oscillator, and output it from a speaker placed at the forward
position.
2. Remove the ORNAMENTAL CAP.
3. Mount this set on the head, and turn on the POWER switch.
4. With this set mounted, rotate the RV1 (Lch) and RV101 (Rch)
so that the volume from the speaker becomes lowest aurally.
Adjust the RV1 (L-CH) or RV101 (R-CH) to the position by
rotating 30 to 45 degrees clockwise from the mechanical center.
mechanical center
5. After adjustment, push and detach the ear receivers to and
from your ears, and use the ear receivers at the position a little
away from your ears to check that a peep howling does not
occur.
If a howling occurred, rotate the RV2 (L-CH) or RV102 (R-
CH) counterclockwise to reduce the volume. As a result of
the reduced volume on either side (RV2 or RV102), if you
feel that the left and right balance is disordered, reduce the
volume on another side until your feeling that something is
wrong is eliminated, so that both sides are balanced.
Adjustment Location:
– ML Board (Side A) –
RV2
RV1
8
speaker
amplifier
+
–
adjusted position
(reference)
– MR Board (Side A) –
RV101
RV102