Section 3 Electrical Adjustments - Sony MDR-RF815R Service Manual

Notes:
1. Use transmitter with check and adjustment already completed.
2. On adjusting the headphones section, use the transmitter as a
jig.
Headphones:MDR-RF815R
Transmitter:TMR-RF815R
Procedure:
Connect an oscillator with attenuator and terminator (600 Ω)
1.
to the transmitter AUDIO IN-A connector (J402).
2. Connect an AC adapter to the transmitter DC IN 9V jack (J404).
3. Connect lead wires to IC301 pin 4, pin 6, pin 7 and GND on
the RX-BASE board.
Connect a resistor 33k Ω between IC301 pin 4 and pin 7.
4.
5. Connect lead wires to the speakers' terminals (L+,L-,R+,R-)
on the RX-BASE board.
3-1. Free run frequency check and adjustment
1. Set the transmitter AUDIO IN-A connector (J402) to no signal.
Note: In this case, operation time is about 4 or 5 minutes.
2. Check the transmitter power indicator (red) lights.
3. Set the transmitter CHANNEL switch to 1.
4. Set the head phones tuning (RV303) to center position.
5. Connect a frequency counter to IC301 pin 4 and GND on the
RX board.
6. Adjust the value of the frequency counter to specification by
RV301 on the RX-BASE board.
Specified Values: 76kHz ± 50Hz.
3-2. Receive frequency check and adjustment
1. Set the transmitter CHANNEL switch to 2.
2. Set the transmitter NOISE FILTER switch to OFF.
3. Input a signal of 1kHz, 316mVrms to transmitter AUDIO IN-
A-L connector only.
4. Keep distance transmitter and headphones to 5 meter over.
5. Set the headphones volume (RV302) to minimum.
6. Set the headphones tuning (RV303) to center position.
7. Connect an oscilloscope CH1 and CH2 to IC301 pin 6 and pin 4.
8. Check the waveform of the oscilloscope to CH1 is demodulated
1kHz signal and CH2 is GND.
9. If CH1 and CH2 are not satisfied step 8, adjust the coil (L301)
on the RX board to satisfied step 8.
10. Set the transmitter CHANNEL switch to 1 or 3.
11. Adjust the headphones tuning (RV303) to receive radio
frequency.
12. Check same step 8.
SECTION 3
ELECTRICAL ADJUSTMENTS
3-3. Carrier modulation check
1.
2.
3.
4.
5.
6.
7.
8.
9.
3-4. Separation check
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Measure the value of the AC volt meter.
11. Check the difference of the L and R to more than 20dB.
12. Input a signal of 1kHz, 316mVrms to transmitter AUDIO IN-
13. Connect an AC volt meter to speakers terminal (R+,R-).
14. Adjust the value of the AC volt meter to specification by
15. Connect an AC volt meter to speakers terminal (L+,L-).
16. Measure the value of the AC volt meter.
17. Check the difference of the L and R to more than 20dB.
Adjustment Location : (See page 6)
— 5 —
Set the transmitter CHANNEL switch to 2.
Set the transmitter NOISE FILTER switch to OFF.
Input a signal of 1kHz, 316mVrms to transmitter AUDIO IN-
A-L connector only.
Adjust the headphones tuning (RV303) to receive radio
freqency.
Set the headphones volume (RV302) to minimum.
Connect an oscilloscope CH1 and CH2 to IC301 pin 6 and pin 4.
Check the waveform of the oscilloscope to CH1 is demodulated
1kHz signal and CH2 is GND.
Connect an AC volt meter to IC301 pin 6 and GND.
Check the value of the AC volt meter to 26mVrms ± 2mV
Set the transmitter CHANNEL switch to 2.
Set the transmitter NOISE FILTER switch to OFF.
Input a signal of 1kHz, 316mVrms to transmitter AUDIO IN-
A-L connector only.
Adjust the headphones tuning (RV303) to receive radio
freqency.
Connect an oscilloscope to CH1 is demodulated 1kHz signal
and CH2 is GND.
Check the waveform of the oscilloscope to CH1 is demodulated
1kHz signal and CH2 is GND.
Connect an AC volt meter with LPF to speakers terminal (L+,L-).
Adjust the value of the AC volt meter to specification by
headphones volume RV302.
Specified Value: 155mVrms
Connect an AC volt meter with LPF to speakers terminal (R+,R-).
A-R connector only.
headphones volume RV302.
Specified Value: 155mVrms