Sony MDR-IF540R, Руководство по обслуживанию

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14
MDR-IF540R
SECTION 3
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. These adjustments should be performed in the order in which
they appear. It is required as a rule to adjust the transmitter
section (TMR-IF540R) before adjusting the headphone
section (MDR-IF540R).
2. Adjustment and measurement should be made on each channel
unless otherwise specified.
3. Adjust on the left channel before adjusting on the right
channel.
4. Supply a power voltage of 9 V to the transmitter section (TMR-
IF540R) and a power voltage of 2.4 V to the headphones
section (MDR-IF540R).
Headphones Section 0 dBV = 315 mVrms
Note:
1. Use the transmitter section (TMR-IF540R) as a jig for
adjusting the headphones section (MDR-IF540R).
Tuning Adjustment
Preparation:
low-frequency
oscillator
attenuator
jig
trans-
mitter
INPUT B
jack (J1)
1 kHz 315 mV (-10 dBV)
stabilized
power (9 V dc)
600 Ω
1. Apply the input to the jig (TMR-IF540R), and connect a
stabilized power to the DC IN 9V jack (J3).
2. Supply 2.4 V dc between BATT (+) and BATT (–) on the BATT
board.
3. Set the RV2 (volume control) on the RX board to the minimum
level.
Connection:
+
+
100
µ
F/16 V
RX board
TP5 (L-ch)
TP4 (R-ch)
distortion meter
Adjustment Method:
1. Connect a distortion meter to TP5 (L-ch) or TP4 (R-ch) on the
RX board.
2. Adjust the L5 (L-ch) or L6 (R-ch) so as to minimize the
reading on the distortion meter.
L-ch L5 Minimum
R-ch L6 Minimum
FM RF
signal generator
Carrier frequency : 2.8 MHz
Modulation
: 1 kHz, 16 kHz deviation
Output level : 34 dB µ V (EMF)
set
SIG
TP1 (GND)
0.1
µ
F
10 k
Ω
+
RX board
level meter
TP4 (R-ch)
Mute ON Position Adjustment
Preparation:
Connection:
Adjustment Method:
1. Connect a level meter to TP4 (R-ch) on the RX board.
2. Short between TP2 and TP3 on the RX board.
3. Write down the reading on the level meter at this time.
4. Remove the short between TP2 and TP3 made in item 2.
5. Adjust the RV1 on the RX board so that the reading on the
level meter is 5 dB to 10 dB below the value written down in
item 3.