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SECTION 3 ELECTRICAL ADJUSTMENTS
Note: 1. The adjustments should be performed in the order given. 2. The transmitter (TMR-RF930) already checked and adjusted should be used.
3-1. Receiving Frequency Check and Adjustment
Preparation:
AF OSC ATT + + � � TMR-RF930 Transmitter MDR-RF930 Headphones
+ �
5m
600 �
AUDIO IN (Lch) 1 kHz 316mVrms
[RX-BASE board] � Conductor Side �
DC voltmeter
oscilloscope
+ �
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. Place the transmitter away from the headphone (MDR-RF930) more than 5 m. 5. Set the volume control (RV301) on the RX-BASE board to the minimum position. 6. Set the tuning control (RV302) on the RX-BASE board to the center position. 7. Connect a DC voltmeter and an oscilloscope between IC301 pin @¡ and ground on the RX-BASE board. 8. After confirming that demodulated 1 kHz waveform (about 13 mV) appears on the oscilloscope, check that the DC voltmeter indicates DC1 V to 1.2 V. 9. If demodulated 1 kHz waveform does not appear on the oscilloscope, or if the voltage is out of the specified value, adjust the air-core coil (L301) on the RX-BASE board so that the demodulated 1 kHz waveform appears on the oscilloscope, and under this condition, adjust finely the air-core coil (L301) so that the DC voltmeter indicates DC1.1 V. 10. Finally, check that signals are received when the channel is changed over to CH1/CH3 on the transmitter, then when the tuning control (RV302) on the RX-BASE board is rotated. Adjustment Location: RX-BASE board (See page 9.)
