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Sony MDR-RF875R, Service Manual

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Sony MDR-RF875R Service Manual Download Page 9

— 9 —

IC301 

7

IC301 

4

IC301 

6

GND

Short

L–

L+

R–

R+

GND

TP

L301
Receive Frequency
Check and  Adjustment

RV302
Corrier Modulation/Separation/ 
MPX Signal Modulation Check

+B
power line

RV301
Free Run Frequency
Check and  Adjustment

(Connect a 33 K

Ω

 resistor)

Adjustment Location :

[RX-BASE BOARD]
(Conductor side)

Summary of Contents for MDR-RF875R

Page 1: ...MDR RF875RK COMPONENT MODEL NAME FOR MDR RF875RK SPECIFICATIONS Headphones Power source DC 2 4 V Built in rechargeable battery Mass Approx 350 g 12 25 oz incl built in rechargeable battery Built in Ni MH rechargeable battery Model name NH AAC Voltage 1 2 V Capacity 1 000 mAh Design and specifications are subject to change without notice Ver 1 0 2000 08 ...

Page 2: ...utomatically Do not allow the self adjusting band to be pulled up otherwise the headphones will be switched on The power turns on Note If a hissing noise is heard move closer to the transmitter TUNING VOL control Notes on chip component replacement Never reuse a disconnected chip component Notice that the minus side of a tantalum capacitor may be damaged by heat Flexible Circuit Board Repairing Ke...

Page 3: ...f colors Set the each leads as illustrated below Precaution for installtion Precaution for installtion Precaution for installtion Head band assy front natural Head band assy front black Head band assy rear green Head band assy rear natural Driver red Driver natural Red Natural From RX BASE board From head band assy front From head band assy rear From SW board Driver R side ANT qa RX BASE board 0 R...

Page 4: ... installtion Set the each leads as illustrated below 7 Remove the two solderings 4 Two screws P 2 8 1 Screw P 2 8 2 Spring 4 Head cushion assy 6 Shassis 5 Two screws P 2 8 7 Head band assy rear 8 Head band assy front From head band assy front From head band assy rear From SW board Groove Groove Groove Groove Groove Groove 6 2 3 HOLDER R ...

Page 5: ...talltion Green Natural Green Natural From head band assy rear From head band assy front From head band assy rear Driver L side 2 Four screws M 2 5 1 Ear pad 6 Ear pad holder L 3 Front plate L assy 8 Driver Four claws 7 Remove the two solderings 4 Two nickle hydrogen batterys 5 Remove the two solderings Groove Groove ...

Page 6: ...ger L Hanger L 1 1 Precaution for installtion Set the each leads as illustrated below 4 Two screws M 2 5 1 Screw M 2 5 3 Head cushion assy 5 Shassis 4 Two screws M 1 7 3 7 Head band assy rear 6 Head band assy front From head band assy front From head band assy rear Groove Groove Groove 6 ...

Page 7: ...p 8 15 Set the transmitter CHANNEL switch to 3 16 Push the headphones tuning switch S301 to receive radio frequency 17 Check same step 8 0 6V 2 3 sec 1 8V GND Requlated power supply DC 1 2V Frequency counter TP IC301 pin4 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 IN ...

Page 8: ... L ch connector only 4 Connect an oscilloscope CH1 to speakers terminal L L and CH2 to IC301 pin 4 and GND 5 Push the headphones tuning switch S301 to receive radio frequency 6 Check the waveform of the oscilloscope that the CH1 is demodulated 1kHz signal and CH2 is GND 7 Set the headphones volume RV302 to max 8 Connect an AC voltmeter with LPF to speakers terminal L L 9 Check the value of the AC ...

Page 9: ...GND TP L301 Receive Frequency Check and Adjustment RV302 Corrier Modulation Separation MPX Signal Modulation Check B power line RV301 Free Run Frequency Check and Adjustment Connect a 33 KΩ resistor Adjustment Location RX BASE BOARD Conductor side ...

Page 10: ...nd fed with regulated dc power supply from battery terminal Voltages are dc with respect to ground under no signal conditions Voltages are taken with a VOM Input impedance 10 MΩ Voltage variations may be noted due to normal production toler ances Waveforms are taken with a oscilloscope Voltage variations may be noted due to normal production toler ances Circled numbers refer to waveforms Signal pa...

Page 11: ...02 VOLUME SPEAKER L CH SPEAKER R CH POWER AMP IC302 MUTE Q304 22 20 FM FE L302 V D A CONV IC303 DETECT IC304 HPF Q306 LPF EQ IC309 IC306 EXPANDER AMP IC307 FF IC305 OSC Q301 SWITCH Q303 10 12 27 S301 TUNING Q305 D Q Q AUTO BLEND MUTE MONO ST SW 1 2 COUNTER PD1 PD1 VCO 21 REG RV301 FREE RUN FREQ IF AMP DECODE IC301 D304 S1 ON OFF SW B Signal path R ch is omitted due to same as L ch FM 16 POWER ...

Page 12: ...MDR RF875R 4 2 SCHEMATIC DIAGRAM 13 14 See page 10 for Note on Schematic Diagrams See page 10 for IC Block Diagrams ...

Page 13: ... 3 D304 B 2 D310 C 2 IC301 A 2 IC302 C 2 IC303 A 1 IC304 B 3 IC305 B 2 IC306 C 5 IC307 C 6 IC308 B 6 IC309 B 5 Q301 B 3 Q303 B 2 Q304 B 2 Q305 B 2 Q306 A 5 Q307 B 5 Semiconductor Location 1 2 3 4 5 6 7 RX SW board power C VOL TUNE See page 10 for Note on Printed Wiring Board ...

Page 14: ... LARGE BATTERY 13 3 046 696 01 HOLDER L 14 3 046 695 01 CHASSIS 15 3 046 698 01 LID L HOLDER 16 3 220 123 01 PLATE L HOUSING ORNAMENTAL 17 3 046 707 01 HOUSING L 18 3 049 953 01 LID L HANGER 19 3 046 705 01 HANGER L 20 3 046 699 01 LID R HOLDER 21 1 678 685 11 RX SW BOARD 22 3 046 697 01 HOLDER R 23 3 046 706 01 HANGER R 24 3 049 954 01 LID R HANGER 25 3 046 708 01 HOUSING R 26 3 046 710 01 CAP R ...

Page 15: ...F 5 00 50V C333 1 163 220 11 CERAMIC CHIP 3PF 0 25PF 50V C336 1 163 245 11 CERAMIC CHIP 56PF 5 00 50V C337 1 163 251 11 CERAMIC CHIP 100PF 5 00 50V C340 1 163 038 11 CERAMIC CHIP 0 1uF 25V C341 1 163 038 11 CERAMIC CHIP 0 1uF 25V C342 1 163 021 91 CERAMIC CHIP 0 01uF 10 00 50V C343 1 163 021 91 CERAMIC CHIP 0 01uF 10 00 50V C344 1 163 038 11 CERAMIC CHIP 0 1uF 25V C345 1 163 038 11 CERAMIC CHIP 0 ...

Page 16: ... METAL CHIP 6 8K 5 1 10W R325 1 216 037 00 METAL CHIP 330 5 1 10W R330 1 216 001 00 METAL CHIP 10 5 1 10W R331 1 216 057 00 METAL CHIP 2 2K 5 1 10W R332 1 216 049 11 RES CHIP 1K 5 1 10W R333 1 216 057 00 METAL CHIP 2 2K 5 1 10W R334 1 216 057 00 METAL CHIP 2 2K 5 1 10W R340 1 216 065 91 RES CHIP 4 7K 5 1 10W R341 1 216 113 00 METAL CHIP 470K 5 1 10W R342 1 216 106 00 METAL CHIP 240K 5 1 10W R343 1...

Page 17: ... 1 216 073 00 METAL CHIP 10K 5 1 10W R400 1 216 025 11 RES CHIP 100 5 1 10W R401 1 216 025 11 RES CHIP 100 5 1 10W R403 1 216 073 00 METAL CHIP 10K 5 1 10W R404 1 216 073 00 METAL CHIP 10K 5 1 10W VARIABLE RESISTOR RV301 1 241 763 11 RES ADJ CARBON 4 7K RV302 1 227 189 11 RES VAR CARBON 20K 20K VOL SWITCH S301 1 771 980 11 SWITCH TACTILE TUNE MISCELLANEOUS 6 1 542 416 11 DRIVER 030F031 8 1 756 109...

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