Sony NC-AA MDR-RF950, Service Manual

Page: 6 / 16

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3-2. Degree of Modulation of Main Carrier (L + R) Check and Adjustment
Preparation:
Procedure:
1. Set the channel of the transmitter to CH2.
2. Turn OFF the noise filter switch on the transmitter.
3. Enter 1 kHz 316 mVrms signal only to the Lch on the transmitter.
4. Set the volume control (RV301) on the RX-BASE board to the minimum position.
5. Connect an AC voltmeter and an oscilloscope between IC 301 pin
@¡
and ground on the RX-BASE board.
6. Rotating the tuning control (RV302) on the RX-BASE board, receive signals.
7. After confirming that demodulated 1 kHz waveform appears on the oscilloscope, check that the AC voltmeter indicates 12 mVrms to
15 mVrms.
8. If out of the specified value, rotate RV404 on the TX-BASE board in the transmitter (TMR-RF950R) so as to attain 13.5 mVrms.
Adjustment Location: TX-BASE board in the transmitter (TMR-RF950R) (See page 8.)
AF OSC
ATT
AUDIO IN (Lch)
1 kHz 316 mVrms
600
Ω
Trans-
mitter Head-
phones
+
–
+
–
TMR-RF950R
MDR-RF950
+
–
+
–
oscilloscope
AC voltmeter
[RX-BASE board] – Conductor Side –