Sony MDRRF-920-R, MDRRF-960-R Service manual

MDR-RF920R/RF960R

SERVICE MANUAL

Ver. 1.1 2006. 08

Photo : MDR-RF960R

MDR-RF920R is the component model block one in the MDR-RF920RK. MDR-RF960R is the component model block one in the MDR-RF960RK.

COMPONENT MODEL NAME FOR MDR-RF920RK/ MDR-RF960RK

MDR-RF920RK MDR-RF960RK

Wireless Stereo Headphones MDR-RF920R MDR-RF960R

Transmitter TMR-RF960R TMR-RF960R

Model

US Model

Canadian Model

SPECIFICATIONS

Headphones

Power source Supplied rechargeable nickelmetal

hydride batteries BPHP550 or commercially available (size AAA) dry batteries

Mass Approx. 270 g (9.6 oz.) incl.

batteries

Design and specifications are subject to change without notice.

HEADPHONES

9-877-525-02

Sony Corporation

Personal Audio Division Published by Sony Techno Create Corporation

MDR-RF920R/RF960R

TABLE OF CONTENTS

Specifications ............................................................................ 1

1. GENERAL ................................................................... 2

2. DISASSEMBLY

2-1. Disassembly Flow ................................................... 3

2-2. Front Plate (R) Assy................................................ 3

2-3. Front Plate (L) Assy ................................................ 4

2-4. SW Board ................................................................ 5

2-5. How to Hang The Tension Spring........................... 5

3. ELECTRICAL ADJUSTMENTS ..........................7

3-1. Free Run Frequency Check and Adjustment........... 7

3-2. Receive Frequency Check and Adjustment ............7

3-3. Carrier Modulation Check ...................................... 7

SECTION 1

GENERAL

3-4. Separation Check ....................................................7

3-5. Free Run Frequency Check and Adjustment........... 8

3-6. Receive Frequency Check and Adjustment ............8

3-7. Carrier Modulation Check ...................................... 8

3-8. Separation Check ....................................................8

4. DIAGRAMS

4-1. Block Diagrams ............................................................... 11

4-2. Schematic Diagram – RX-Base Section (RF920R)– ...... 12

4-3. Schematic Diagram – RX-Base Section (RF960R)– ...... 13

4-4. Printed Wiring Boards– RX-Base Section– .................... 14

4-5. Schematic Diagram – RX-FE Section–........................... 15

4-6. Printed Wiring Boards– RX-FE Section– .......................16

5. EXPLODED VIEWS ................................................. 17

6. ELECTRICAL PARTS LIST ..................................18

This section is extracted from instruction manual.

5 Turn up the volume to a moderate

level with the VOL control.

A MDR-RF960R

Press the TUNE button briefly for automatic tuning of the headphones.

If you do not receive a clear audio signal, press it again.

TUNE

TUNE button

VOL control

B MDR-RF920R

Tune the headphones into the frequency of the transmitter with the TUNE control until you can hear the audio signal loud and clear.

The headphones automatically turn

off when the y are taken off – Auto power on/off function

Do not pull up the self-adjusting band when not in use, as this will consume the battery power.

Flexible Circuit Board Repairing

• Keep the temperature of the soldering iron around 270°C

during repairing.

• Do not touch the soldering iron on the same conductor of the circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

TUNE

TUNE control

VOL control

Follow steps 3 and 5 above until the receiving performance becomes better.

• This set can be disassembled in the order shown below.

2-1. DISASSEMBLY FLOW

2-2. Front Plate (R) assy

Set

MDR-RF920R/RF960R

SECTION 2

DISASSEMBLY

(Page 3)

2-3. Front Plate (L) assy

(Page 4)

Note: Follow the disassembly procedure in the numerical order given.

2-2. FRONT PLATE (R) ASSY

craw

housing cap (R)

to RX BATTERY board

RED

2-4. SW baord

(Page 5)

NAT

GRN

Remove solder

(4 places)

RX-BASE board

NAT

craws

housing (R) sub assy

RX-BASE board

Remove solder

(2 places)

RED

to RX-BASE board

NAT

driver (R-CH)

to driver (L-CH)

three screws

(+B2.6)

front plate (R) sub assy

ear pad (R)

MDR-RF920R/RF960R

)

2-3. FRONT PLATE (L) ASSY

Remove solder (4 places)

RED

housing (L) sub assy

tow screws (DIA. 2)

driver (L-CH)

Remove solder

(2 places)

GRN

to RX-BASE board

RX BATTERY

board

to SW board

NAT

RED

to RX-BASE board

three screws

(+B2.6)

front plate (L) sub assy

NAT

ear pad (L

)

2-4. SW BOARD

hunger (L)

SW board

MDR-RF920R/RF960R

2-5. HOW TO HANG THE TENSION SPRING

suspender

hanger lid (L)

two screws (B2.6

two screws (B2.6)

housing (L) sub assy

Note for installation : Insert the end of the

suspender assy under the S101 on the SW board.

SW board

housing (L) sub assy

tensin spring

suspender

S101

MDR-RF920R/RF960R

SET THE LEAD WIRES

Set the each lead wires as illustrated below.

wires

(R-CH)

wires

housing (L)housing (R)

(L-CH)

groove

wire

wires

head band

MDR-RF920R

+ –+–

IC301 pin6

IC301 pin4

OSCILLOSCPE

CH1 CH2

Notes:

1. Use transmitter with check and adjustment alreadycompleted.

2. On adjusting the headphones section, use the transmitter as a

Procedure:

1. Connect an oscillator with attenuator and terminator (600 Ω)

2. Connect an AC adapter to the transmitter DC IN 9V jack

3. Connect a DC 2.4V to the +B power line externally.

4. Connect lead wires to IC301 pin 4, pin 6, pin 7 and GND on

5. Connect a resistor 33k Ω between IC301 pin 4 and pin 7.

6. Connect lead wires to the speakers’ terminals (L+,L-,R+,R-)

3-1. Free Run Frequency Check and Adjustment

1. Set the transmitter AUDIO IN-B connector (J402) to no signal.

Note: In this case, operation time is about 5 or 10 minutes. Perform confirmation for less than 5 minutes.

2. Check the transmitter power indicator (red) lights.

3. Set the transmitter CHANNEL switch to 1.

4. Set the RV303 (TUNE) to the center position.

5. Connect a frequency counter to IC301 pin 4 and GND on the

6. When the frequency dose not satisfy the specified value, adjust

7. Remove a 33 kΩ resister between IC301 pin 4 and pin 7.

Setting :

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-

4. Keep distance between transmitter and headphones to 5 meters

5. Set the headphones volume (RV302) to minimum.

6. Set the RV303 (TUNE) to the center position.

7. Connect an oscilloscope CH1 and CH2 to IC301 pin 6 and

8. Check the waveform of the oscilloscope to CH1 is demodulated

9. If CH1 and CH2 are not satisfied in step 8, adjust the coil

10. Set the transmitter CHANNEL switch to 1.

11. Adjust the RV303 (TUNE) to receive a signal.

12. Check same step 8.

13. Set the transmitter CHANNEL switch to 3.

14. Adjust the RV303 (TUNE) to receive a signal.

15. Check same step 8.

SECTION 3

ELECTRICAL ADJUSTMENTS

jig.

Headphones: MDR-RF920R Transmitter: TMR-RF960R

to the transmitter AUDIO IN-B connector (J402).

(J403).

the RX-BASE board.

on the RX-BASE board.

RX-BASE board, then confirm the frequency within 76kHz ± 50Hz

the value of the frequency counter to specification by R V301 on the RX-BASE board.

Specified values: 76kHz ± 50Hz.

Frequency counter

+ –

B(L-ch) connector only.

over.

pin 4.

1kHz signal and CH2 is GND.

(L301) on the RX board to satisfied step 8.

Confirm the signal with stereo.

IC301 pin

MDR-RF920R/RF960R

Setting :

3-3. Carrier Modulation Check

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 INB (L-ch) connector only.

4. Set the headphones volume (RV302) to minimum.

5. Connect an oscilloscope CH1 and CH2 to IC301 pin 6 and pin 4.

6. Adjust the tuning control (R V303) to receive radio frequency .

7. Check the waveform of the oscilloscope that the CH1 is demodulated 1kHz signal and CH2 is GND.

8. Connect an AC voltmeter with LPF to IC301 pin 6 and GND.

9. Check the value of the AC voltmeter to 26mVrms ± 2mV.

Setting :

Digital voltmeter (AC range)

LPF

+ –

2.2K 33000P

IC301

pin6

3-4. Separation Check

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 INB (L-ch) connector only.

4. Connect an oscilloscope CH1 to speakers terminal (L+,L-) and CH2 to IC301 pin 4 and GND.

5. Adjust the tuning control (R V303) to receive radio frequency .

6. Check the waveform of the oscilloscope that the CH1 is demodulated 1kHz signal and CH2 is GND.

7. Connect an AC voltmeter with LPF to speakers terminal (L+,L).

8. Adjust the value of the AC voltmeter to specification by headphones volume RV302.

Specified values: 155mVrms

9. Connect an AC voltmeter with LPF to speakersterminal (R+,R-).

10. Measure the value of the AC voltmeter.

11. Check the difference of the L and R to more than 20dB.

12. Input a signal of 1kHz, 316mV rms to transmitter AUDIO INB(R-ch) connector only.

13. Connect an AC voltmeter with LPF to speakers terminal (R+,R-).

14. Adjust the value of the AC voltmeter to specification by headphones volume RV302.

Specified values: 155mVrms

15. Connect an AC voltmeter with LPF to speakers terminal (L+,L-).

16. Measure the value of the AC voltmeter.

17. Check the difference of the L and R to more than 20dB.

Setting :

Digital voltmeter (AC range)

L+ / R+

L– / R–

–

OSCILLOSCPE

IC301 pin6

OSCILLOSCPE

CH1 CH2

L+

–+–

L–

CH1 CH2

+ –+–

IC301 pin

IC301 pin4

+ 15 hidden pages