Sony MDRRF-830 Service manual
MDR-RF830
SERVICE MANUAL
Ver 1.0 1998.07
MDR-RF830 is the component model block one in the MDR-RF830RK.
COMPONENT MODEL NAME FOR MDR-RF830RK
Wireless Stereo Headphones MDR-RF830
Transmitter TMR-RF830R
UK Model
SPECIFICATIONS
Power source DC 3 V: 2 × R6 (size AA) battery
Mass Approx. 215 g (7.6 oz.) incl.
Design and specifications are subject to change
without notice.
or 2 × supplied
NC-AA-HJ Ni-Cd
rechargeable battery
Ni-Cd batteries
WIRELESS STEREO HEADPHONES
MICROFILM
SECTION 1
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
1-1. RX BOARD, FE BOARD (R-CH)
3
Cover (R), hanger
7
FE board
6
Remove
solder
4
RX board
9
Screw
(M1.7
×
4)
0
Spacer
8
Remove solder
1
Screws (+P2 × 12)
2
Screws (+P2 × 8)
5
Plate, RX shield
1-2. MDD02 (R-CH)
!¡
SW1
6
MDD02 (R-CH)
5
Screw (M1.7 × 4)
2
Screw (+P2 × 8)
3
Holder, ball shaft
4
Housing (R) assy
7
Remove solder
— 2 —
— 2 —
1
Pad, ear
1-3. CASE, BATTERY, MDD01 (L-CH)
5
Screws (+P2 × 12)
3
Screws (+P2 × 8)
2
Cover, battery
6
Case, battery
1
Pad, ear
!¡
Screw (M1.7 × 4)
0
Housing (L) assy
!£
Remove solder
!™
MDD01 (L-CH)
7
Remove solder
8
Screw (+P2 × 8)
9
Holder, ball shaft
4
Cover (L), hanger
— 3 —
SECTION 2
ELECTRICAL ADJUSTMENTS
Notes:
1. Use transmitter with check and adjustment alreadycompleted.
2. The transmitter section adjustments should be completed before
performing the headphones section adjustment.
3. On adjusting the headphones section, use the transmitter as a jig.
Headphones
MDR-RF830
Transmitter
TMR-RF830R
Procedure:
AF OSC
L-CH (J403)
1kHz 316mVrms (–7.8dB)
ATT
600
Ω
Jig
Transmitter
J404
power supply
(DC 9V)
1. Feed a signal to jig (transmitter) and connect a power supply to
DC IN 9V jack (J404).
Receive frequency check and adjustment
1. Set the transmitter channel to CH2.
2. Set the transmitter noise filter SW to OFF .
3. Input a signal of 1kHz 316mVrms to onl y the transmitter LCH (J403).
4. Place transmitter and headphones at a distance of more than 5m
apart.
5. Set the VOL (RV301) to MIN.
6. Position RX board TUNING VOL (RV302) to the center .
7. Connect a digital voltmeter (DC range) and an oscilloscope
between
IC301 pin @¡ and GND.
8. First check to make sure that a demodulated waveform of 1kHz
(appr oximately 13mVrms) is outputted to the oscilloscope ,
then
check to make sure the DC voltmeter reading is DC 1 to 1.2V .
9. If a demodulated waveform of 1kHz is not outputted to the
oscilloscope or if the DC level is not within the range specified
above, adjust the RX board L301 so that a demodulated
waveform of 1kHz is outputted to the oscilloscope and while
the wave-form is outputted, further fine adjust the L301 so that
the DC voltmeter reading is DC1.1V.
10. When completed, make sure signals can be received when
switching the transmitter channel to CH1 or CH3 by turning
RX board TUNING VOL (RV302).
Separation check and adjustment
1. Set the transmitter channel to CH2.
2. Set the transmitter noise filter SW to OFF .
3. Input a signal of 1kHz 316mVrms to onl y the transmitter LCH (J403).
4. Connect an digital voltmeter (AC range) and oscilloscope to
the L-CH speaker outputs (both sides of MDD01).
5. Receive signals by turning the TUNING VOL (RV302).
6. Adjust the VOL (RV301) so that the RX board L-CH speaker
outputs (both sides of MDD01) are 155mVrms.
7. Connect an digital voltmeter (AC range) and oscilloscope to
the R-CH speaker outputs (both sides of MDD02) and measure
the voltages.
8. At this time, check to make sure the level separation of L-CH
and R-CH speaker outputs is more than 20dB. If the separation
is less than 20dB, turn R V303 on the RX boar d so that the RCH output is minimal, then check to see if the level separation
of L-CH and R-CH speaker outputs is more than 20dB.
9. Input a signal of 1kHz 316mVrms to only the transmitter R-CH
(J402).
10. Adjust the VOL (RV301) so that the RX boar d R-CH speaker
outputs (both sides of MDD02) are 155mVrms.
11. Connect an digital voltmeter (AC range) and oscilloscope to
the L-CH speaker outputs (both sides of MDD01) and measure
the voltages.
12. At this time, check to make sure the level separation of L-CH
and R-CH speaker outputs is more than 20dB.
Connection points and Adjustment Location:
RX BOARD (See page 5)
Connection points and Adjustment Location:
RX BOARD (See page 5)
— 4 —
Connection points :
Digital voltmeter
(AC range)
Oscilloscope
Digital voltmeter
(DC range)
[ RX BOARD ] (Conductor side)
Adjustment Location :
Oscilloscope
RV302
Tuning Knob
[RX BOARD] (Component side)
RV301
VOL Knob
RV303 : Separation Adjustmen
L301 : Receive Frequency Adjustment
— 5 —
t
• IC BLOCK DIAGRAMS
IC301 CXA1611N-T4
SECTION 3
DIAGRAMS
DETUNE DET
CONTROL
VCC
RIPPLE FILTER
DET OUT
AFC AGC
AFC AGC
AM IF OUT
GND
METER
FM IF IN
24 23 22 21 20 19 18 17 16 15 14 13
AM IF IN
FM/AM
BAND SELECT
1 2 3 4 5 6 7 8 9 10 11 12
GND
DETUNE DET
IC302 LA4533M
POWER
1
P/SW
IN1
PRE GND
IN2
REF
SWITCH
2
3
4
5
BIAS
FM DISCRI
AMP1
AMP2
AM OSC
MUTE
CIRCIUT
FM•IF
DISCRI
AM•IF
DET•AGC
AFC
FM OSC
10
MT/SW
OUT1
9
8
POWER GND
7
OUT2
6
VCC
TUNING
METER
DETUNE
DET
REG OUT
FM RF
FM•FE
AM RF IN
RIPPLE
FILTER
AM•FE
REGULATOR
NC
FM RF IN
GND
FM/AM
FE OUT
— 6 —
3.2 SCHEMATIC DIAGRAM • Refer tp page 6 IC Block Diagrams.
MDR-RF830
Note on Schematic Diagram:
• 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 Ω and 1/
¢
•
• U : B+ Line.
• H : adjustment for repair.
• Power voltage is dc 3 V and fed with regulated dc power supply
• Voltages are dc with respect to g round under no-signal conditions.
• Voltages are taken with a VOM (Input impedance 10 MΩ).
• Waveforms are taken with a oscilloscope.
• Circled numbers refer to waveforms.
• Signal path.
: internal component.
from battery terminal.
Voltage variations may be noted due to normal production tolerances.
Voltage variations may be noted due to normal production tolerances.
F
4
W or less unless otherwise specified.
WA VEFORM
r
1
10mVp-p
20.4
µ
sec
IC301 @¡
— 9 — — 10 —
VOL T/DIV : 2m V AC
TIME/DIV : 20 µsec
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