SONY MDRRF940R
Manual de Servicio

MDR-RF940R
Adjustment for Separation Preparation:
AF OSC AC voltmeter ATT + + � � TMR-RF940R Transmitter MDR-RF940R Headphones + �

600 �

input plug (Lch or Rch) 400 Hz 316 mVrms

speaker out (Lch or Rch)

Procedure: 1) Input a signal of 400 Hz 316 mVrms only to Lch of the adjusted transmitter. 2) Turn RV91 on the RX board so that the speaker out of Lch becomes 155 mVrms. 3) Turn RV61 on the RX board so that the speaker out of Rch becomes minimum. 4) At this time, confirm the separation between Lch and Rch should be over 18 dB. 5) Then, input a signal of 400 Hz 316 mVrms only to Rch of the transmitter. 6) At this time, confirm the separation between Rch and Lch should be over 18 dB. Adjustment Location: RX Board Confirmation without a spectrum analyzer Please confirm the units by following procedure shown below. Here a series of procedure which can be performed without a spectrum analyzer is introduced. Tuning frequency confirmation Preparation:
AF OSC DC voltmeter ATT + + � � TMR-RF940R Transmitter 5m MDR-RF940R Headphones RX Board TP2 + �

600 � input plug

Procedure: 1) Input any signal including music into TMR-RF940R and place the unit the point where is far from MDR-RF940R and place the unit in a location where is far from by 5 m. 2) Measure the DC voltage at the test point TP2 of RX board of MDR-RF940R. This DC voltage corresponds to the S-curve voltage of FM detection characteristics as shown below.
Spec. DC1.1 ± 0.1 V 0 f

AF signal or music

If tuned frequency is in the area covered by AFC, the center voltage changes when CT41 (channel 1) CT42 (channel 2) is turned. Adjustment Location:
[RX Board] � Side A �

PRINTED WIRING BOARD
� MDR-RF940R Service Manual page 5. (Location F � H, 4 � 6)
[RX Board] � Side A �

RV91 IC41 CT41 CT42 RV61
+ � DC voltmeter

Sony Corporation
9-923-238-81
Personal A&V Products Company

98E0539-1 Printed in Japan © 1998. 5 Published by Quarity Engineering Dept. (Shibaura)

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