Sony MDR-RF450 User manual

Ver 1.0 1998.06
Headphone
Charging and using hours
Approx. charging hours Approx. using time*
1 50 minutes
24** 20 hours
* at 1kHz 1mW + 1mW output
** the hours required to fully charge empty batteries
Battery life
Battery Approx. hours*
Sony alkaline battery LR6 (SG) 60
Sony battery R6P (SR) 30
* at 1kHz 1mW + 1mW output
Power source DC 3V : 2 x R6 (size AA) battery or 2 x supplied
NC-AA-HJ Ni-Cd rechargeable battery
Mass Approx. 215g (7.6oz.) incl.Ni-Cd batteries (MDR-RF430RK)
Approx. 265g (9.4oz.) incl.Ni-Cd batteries (MDR-RF450RK)
Supplied Ni-Cd rechargeable batteries
Model name NC-AA-HJ
Voltage 1.2V
Capacity 600mAh
Design and specifications are subject to change without notice.
MICROFILM
MDR-RF430/RF450
SERVICE MANUAL
WIRELESS STEREO HEADPHONES
AEP Model
MDR-RF430RK MDR-RF450RK
Wireless Headphones MDR-RF430 MDR-RF450
Transmitter TMR-RF450R TMR-RF450R
COMPONENT MODEL NAME FOR MDR-RF430RK/RF450RK
SPECIFICATIONS
MDR-RF430 is the component model block one in the MDR-RF430RK.
MDR-RF450 is the component model block one in the MDR-RF450RK.
Illustration : MDR-RF430 Illustration : MDR-RF450

– 2 –
SECTION 1
DISASSEMBLY
Note:Followthedisassemblyprocedureinthenumericalordergiven.
1-1. RX BOARD, FE BOARD, RECEIVER (R-CH), SUSPENDER REMOVAL
1-2. BATTERY CASE, RECEIVER (L-CH), SUSPENDER REMOVAL
MDR-RF430
2 Screws +P 2x10
9 Screw
(M1.7x4)
!™ Screw
+P 2x6
3 Screws +P 2x5
!¢ Screw (M 1.7x4)
7 Remove
solder
RX shield plate
!§ Remove solder
Hanger cover (R)
Spacer Hanger (R)
Suspender
Head band
5 RX board
Housing (R) assy
MDD02 (R-CH)
SW1
Ball shaft holder
Ear pa
d
!¡
!¶
1
!∞
!£
4
8
6
!º
FE board
2 Screws +P 2x10
7 Screw +P 2x6
3 Screws +P 2x5
!¡ Remove solder
Hanger cover (L
)
Suspender
Head band
Battery cover
Battery case
Housing (L) assy
Hanger (L)
MDD01 (L-CH)
Ball shaft holder
Ear pad
9 Screw (M 1.7x4)
1
!º
4
6
!™
8
5

– 3 –
1-1. RECEIVER (R-CH), RX BOARD, FE BOARD, SUSPENDER ASSY REMOVAL
1-2. RECEIVER (L-CH), SUSPENDER ASSY REMOVAL
MDR-RF450
Hanger (R)
Hanger cover (R)
Housing (R)
!£ Remove
solder
3 Remove
solder
0
9
5
4
1
9
!¢ !¡
!∞
!§
!™
8
!¶
SW
board
Surpport switch
MDD02 (R-CH)
RX shield plate
Claw
2 Screws
(M 1.7x4)
Ear pad
7 Screws (M1.7x4)
6 Screws +P 2x8
Front plat (R) assy
Screw
(M1.7x4)
RX board
FE board
Head band
Suspender
Ear pad
2 Screws
(M 1.7x5) tapping
0 Screws (M 1.7x4)
Head band
Hanger cover (L)
Suspender
3 Remove solder
MDD01 (L-CH)
9 Screws +P 2x8
Front plate (L) assy
Claw
Housing (L)
Hanger (L)
Battery cove
r
5
1
!™
6
!¡
8
7
6
4

– 4 –
SECTION 2
ELECTRICAL ADJUSTMENTS
Separation check and adjustment
1. SetthetransmitterchanneltoCH2.
2. SetthetransmitternoisefilterSWtoOFF .
3. Inputasignalof1kHz316mVrmstoonl ythetransmitterL-c h
(J403).
4. Connectandigitalvoltmeter(ACrange)andoscilloscopeto
theL-chspeakeroutputs(bothsidesofMDD01).
5. Receivesignalsb yturningthe TUNINGVOL(RV302).
6. Adjustthe VOL(RV301)sothattheRXboar dL-c hspeaker
outputs(bothsidesofMDD01)are155mVrms.
7. Connectandigitalvoltmeter(ACrange)andoscilloscopeto
theR-chspeakeroutputs(bothsidesofMDD02)andmeasure
thevoltages.
8. Atthistime,checktomakesurethelevelseparationofL-ch
andR-chspeakeroutputsismorethan20dB.Iftheseparation
islessthan20dB, turnR V303ontheRXboar dsothattheR-c h
outputisminimal,thenchecktoseeifthelevelseparationofL-
chandR-chspeakeroutputsismorethan20dB.
9. Inputasignalof1kHz316mVrmstoonl ythetransmitterR-c h
(J402).
10. Adjustthe VOL(RV301)sothattheRXboar dR-c hspeaker
outputs(bothsidesofMDD02)are155mVrms.
11. Connectandigitalvoltmeter(ACrange)andoscilloscopeto
theL-chspeakeroutputs(bothsidesofMDD01)andmeasure
thevoltages.
12. Atthistime,checktomakesurethelevelseparationofL-ch
andR-chspeakeroutputsismorethan20dB.
Receive frequency check and adjustment
1. SetthetransmitterchanneltoCH2.
2. SetthetransmitternoisefilterSWtoOFF .
3. Inputasignalof1kHz316mVrmstoonl ythetransmitterL-c h
(J403).
4. Placetransmitterandheadphonesatadistanceofmorethan5m
apart.
5. Setthe VOL(RV301)toMIN.
6. PositionRXboar d TUNINGVOL(RV302) tothecenter .
7. Connectadigitalvoltmeter(DCrange)andanoscilloscopebe-
tweenIC301pin @¡ andGND.
8. Firstchecktomakesurethatademodulatedwaveformof1kHz
(appr oximatel y13mVrms)isoutputtedtotheoscilloscope ,then
chec ktomakesuretheDCv oltmeterreadingisDC1–1.2V .
9. Ifademodulatedwaveformof1kHzisnotoutputtedtotheos-
cilloscopeoriftheDClevelisnotwithintherangespecified
above,adjusttheRXboardL301sothatademodulatedwave-
formof1kHzisoutputtedtotheoscilloscopeandwhilethewave-
formisoutputted,furtherfineadjusttheL301sothattheDC
voltmeterreadingisDC1.1V .
10. Whencompleted,makesuresignalscanbereceivedwhenswitch-
ingthetransmitterchanneltoCH1orCH3byturningRXboard
TUNINGVOL (RV302).
Connection points andAdjustment Location :
RXboard(Seepage5)
Note :
1. Usetransmitterwithcheckandadjustmentalreadycompleted.
2. Thetransmittersectionadjustmentsshouldbecompletedbefore
performingtheheadphonessectionadjustment.
3. Onadjustingtheheadphonessection,usethetransmitterasa
jig.
Headphones Transmitter
MDR-RF430 TMR-RF450R
MDR-RF450
Setting :
Transmitter
J404
power supply
(DC 11V)
L-CH (J403)
1kHz 316mVrms (–7.8dB)
AF OSC
ATT Jig
600
Ω
Connection points andAdjustment Location :
RXboard(Seepage5)
1. Feedasignaltojig(transmitter)andconnectapowersupplyto
DCIN9Vjack(J404).

– 5 –
Connection points :
Adjustment Location :
RV302
Tuning Knob
RV301
VOL Knob
L301 : Receive Frequency Adjustment
RV303 : Separation Adjustmen
t
[RX BOARD] (Component side)
[ RX BOARD ] (Conductor side)
oscilloscope
digital voltmeter
(AC range)
oscilloscope
digital voltmeter
(DC range)

– 6 –
rIC BLOCK DIAGRAMS
IC301 CXA1611N-T4
IC302 LA4533M
24 23 22 21 20 19 18 17 16 15 14 13
1 2 3 4 5 6 7 8 9 10 11 12
REGULATOR
AM•FE
FM•FE
RIPPLE
FILTER
TUNING
METER
DETUNE
DET
FM•IF
DISCRI
AM•IF
DET•AGC
DETUNE DET CONTROL VCC RIPPLE FILTER DET OUT AFC AGC AFC AGC AM IF OUT GND METER FM IF IN AM IF IN FM/AM BAND SELECT
DETUNE DET
GND
FM DISCRI
AM OSC
AFC
FM OSC
REG OUT
FM RF
AM RF IN
NC
FM RF IN
GND
FM/AM
FE OUT
POWER
SWITCH MUTE
CIRCIUT
BIAS
1
2
3
4
56
7
8
9
10 MT/SW
OUT1
POWER GND
OUT2
VCC
P/SW
IN1
PRE GND
IN2
REF
AMP2
AMP1
SECTION 3
DIAGRAMS

– 9 – – 10 –
MDR-RF430/RF450
rRefer to page 6 for IC Block Diagrams.
Note:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
•¢: internal component.
•U: B+ Line.
•H: adjustment for repair.
• Power voltage is dc 3V and fed with regulated dc power
supply from battery terminal.
• Voltages are dc with respect to ground under no-signal
conditions.
• Voltagesare taken with aVOM(Input impedance 10 MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
F
rWAVEFORM
1
IC301 @¡ VOLT/DIV : 2m V AC
TIME/DIV : 20 µsec
10mVp-p
20.4
µ sec
3-2. SCHEMATIC DIAGRAM

– 11 –
SECTION 4
EXPLODED VIEWS
NOTE :
• -XX, -X mean standardized parts, so they
may have some difference from the original
one.
• Items marked “ * ”are not stocked since they
are seldom required for routine service. Some
delay should be anticipated when ordering
these items.
• The mechanical parts with no reference
number in the exploded views are not
supplied.
• Hardware (# mark) list and accessories and
packing materials are given in the last of this
parts list.
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
4-1. MDR-RF430
1 4-994-129-01 PAD, EAR
2 X-4950-086-1 HOUSING (R) ASSY
3 4-994-119-01 HANGER (R)
4 4-992-281-01 HOLDER, BALL SHAFT
5 4-210-280-01 PLATE, RX SHIELD
*6 A-4542-510-A RX BOARD, COMPLETE
7 4-994-121-01 COVER (R), HANGER
8 3-713-791-01 SCREW (M1.7X4), TAPPING, P2
9 4-995-597-01 SPACER
10 4-994-124-01 SUSPENDER
11 4-994-118-01 BAND, HEAD
12 4-994-123-01 COVER, BATTERY
13 X-4950-087-1 HOUSING (L) ASSY
14 4-995-475-01 SPRING, TENSION
15 4-994-130-01 TERMINAL (+), BATTERY
16 4-994-132-01 TERMINAL (MIDWAY), BATTERY
17 4-993-020-01 CASE, BATTERY
18 4-994-131-01 TERMINAL (-), BATTERY
19 4-994-122-01 COVER (L), HANGER
20 4-994-120-01 HANGER (L)
22 3-831-441-99 CUSHION, SPEAKER
*24 A-4542-531-A FE BOARD, COMPLETE
MDD01 1-505-117-21 RECEIVER (L-CH)
MDD02 1-505-117-21 RECEIVER (R-CH)
SW1 1-771-249-11 SWITCH, PUSH (1 KEY) (POWER)
#1
#1
#3
#3 #2
#2
SW1
1
1
2
3
4
4
5
6
7
8
8
8
8
8
9
10
11
12
13
14 15 16
17
18
19
20
22
MDD02
MDD01
24
14

– 12 –
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
51 4-977-785-01 PAD, EAR
52 X-4950-101-1 PLATE (R) ASSY, FRONT
53 4-999-774-01 REGISTER, HOUSING
54 4-999-773-01 HOUSING (R)
*55 A-4542-510-A RX BOARD, COMPLETE
56 4-999-769-01 COVER (R), HANGER
57 3-713-791-01 SCREW (M1.7X4), TAPPING, P2
58 4-210-255-01 SUPPORT, SWITCH
*59 1-670-357-11 SW BOARD
60 4-999-767-01 HANGER (R)
61 3-318-203-62 SCREW (B1.7X4), TAPPING
*62 4-999-791-01 PANEL, BACK
*63 4-999-792-01 CASE
64 4-978-519-01 CUSHION, HEAD
65 4-999-765-01 BAND, HEAD
66 4-999-771-01 SUSPENDER
67 4-978-518-02 BASE, SUSPENDER
68 4-999-768-01 COVER (L), HANGER
69 4-999-770-01 BATTERY COVER
70 4-210-258-01 TERMINAL (MIDWAY), BATTERY
71 4-210-256-01 TERMINAL (+), BATTERY
72 4-210-257-01 TERMINAL (-), BATTERY
73 4-999-766-01 HANGER (L)
74 4-999-772-01 HOUSING (L)
75 X-4950-100-1 PLATE (L) ASSY, FRONT
*77 A-4542-531-A FE BOARD, COMPLETE
MDD01 1-505-117-21 RECEIVER (L-CH)
MDD02 1-505-117-21 RECEIVER (R-CH)
4-2. MDR-RF450
#4
#4
51
51
52
53
53
54
55
MDD02
56
57
57
57
57
57
58
59
60
61
61
62
63
64
65
66
67
68
69
70 72
71
73
74
75
MDD01
77