Sony TMRF-450-R Service manual
TMR-RF450R
SERVICE MANUAL
Ver 1.0 1998.06
TMR-RF450R is the component model block one in MDR-RF430RK/RF450RK.
COMPONENT MODEL NAME FOR MDR-RF430RK/RF450RK
MDR-RF430RK MDR-RF450RK
Wireless Stereo Headphones MDR-RF430 MDR-RF450
Transmitter TMR-RF450R TMR-RF450R
AEP Model
SPECIFICATIONS
General
Carrier frequency 433.40 – 434.40 MHz
Channel Ch1, Ch2, Ch3
Modulation FM stereo
Frequency response 20 – 20,000Hz (MDR-RF430RK)
Transmitter
Power source DC 9V : supplied AC power adaptor
Audio input Phono jacks / stereo mini jack
Dimensions Approx. 120 mm dia x 290 mm
Mass Approx. 155g (5.5oz.)
Design and specifications are subject to change without notice.
18 – 22,000Hz (MDR-RF450RK)
(4 3/4 x 11 1/2 in.) (w/h)
MICROFILM
RF STEREO TRANSMITTER
SECTION 1
)
DISASSEMBLY
Note : Follow the disassembly procedure in the numerical order given.
1-1. TX BOARD REMOVAL
Cabinet (Upper
3
VCO board
6
Remove solder
5
TX shield plate
8
2
ANT board
7
Remove solder
TX board
4
– 2 –
1
Screws +P 2x10
Cabinet (Lower)
SECTION 2
S402
Channel Select Switch
RV403 (R-CH)
RV402 (L-CH)
S401
Noise Filter ON/OFF Switch
J402
(R-CH)
RV404 : Main Carrier
Modulation Adjustment
RV401 : Sub-Carrier (L– R) Modulation Adjustment
RV405 : Sub-Carrier Frequency Adjustment
Send Frequency
Adjustment
J403
(L-CH)
[TX BOARD] (Component side)
r
ELECTRICAL ADJUSTMENTS
Note :
1. The transmitter section adjustments should be completed before
performing the headphones section adjustment.
2. On adjusting the transmitter section, use the headphones as a
jig.
Transmitter Headphones
TMR-RF450R
MDR-RF430
MDR-RF450
Setting :
AF signal
generator
set
TMR-RF450R
L-CH (J403)
telescopic
antenna
frequency counter
13cm
set
TMR-RF450R
Sub-Carrier Frequency Check and Adjustment
1. Set the noise filter SW to OFF.
2. Set the channel to CH2.
3. Input a signal of 1kHz 316mVrms to only the L-ch (J403).
4. Connect a frequency counter and an oscilloscope between the
Q409 emitter and GND.
5. Set the TX board L-ch (J403) input to OFF (not doing so will
cause modulation in the sub-carrier, preventing correct measurement)
6. Check to make sure the frequency counter reading is 48 –52kHz.
If the measured value is other than the specified value, adjust
the frequency to 50kHz by turning the R V405 on the TX board.
In addition, check to make sure the oscilloscope waveform is as
follows :
3.4–3.8Vp-p
(Perform the check and adjustment within one minute since the
transmitter AUTO OFF function will be activated approximately
one minute after setting the transmitter L-ch input to OFF . If the
AUTO OFF function activates, set the L-ch input to ON, set TX
board to AUTO ON, set the L-ch input again to OFF, then make
the check adjustment.)
Connection points and Adjustment Location :
TX board (See page 4)
Connection points :
[ TX BOARD ] (Conductor side)
digital voltmeter
(AC range)
oscilloscope
Send Frequency Check and Adjustment
1. Set the noise filter SW to OFF.
2. Input a signal of 1kHz 40mVrms to only the L-ch (J403).
3. Connect a telescopic antenna to the frequency counter input and
4. Place TX board close to the frequency counter, then measure the
If the measured values are other than the values specified above,
adjust the frequencies by turning RV402 and RV403 on the TX
board. When completed with adjustment, recheck the frequencies
of CH1, CH2 and CH3.
Connection points and Adjustment Location :
Sub-Carrier (L-R) Modulation Check and Adjustment
1. Set the noise filter SW to OFF.
2. Set the channel to CH2.
3. Input a signal of 1kHz 316mVrms to only the L-ch (J403).
4. Measure the pin 1 voltage of the TX board IC403 using an
headphones
MDR-RF430
MDR-RF450
battery terminal (DC 3V)
extend the antenna to a length of approximately 13cm.
frequencies of CH1, CH2 and CH3 and make sure the values are
as follows:
CH1 : 433.3 – 433.5MHz
CH2 : 433.8 – 434.0MHz
CH3 : 434.3 – 434.5MHz
TX board (See page 4)
digital voltmeter (AC range) and make sure the value is 220 –
250mVrms. If the measured value is other than the specified
value, adjust to 235mVrms by turning the RV401 on the TX
board.
Main Carrier Modulation Check and Adjustment
1. Set the channel to CH2.
2. Set the noise filter SW to OFF.
3. Input a signal of 1kHz 316mVrms to only the transmitter Lch
(J403).
4. Set headphones VOL (RV301) to MIN.
5. Connect an digital voltmeter (AC range) and oscilloscope between IC301 pin @¡ and GND on RX board (headphones).
6. Receive signals by turning headphones TUNING VOL (RV302).
7. First check to make sure that a demodulated waveform of 1kHz
is outputted to the oscilloscope, then check to make sure the
digital voltmeter (AC range) reading is AC 12 –15mV rms. If the
reading is not within the specified range, turn R V404 on the TX
board so that the reading is 13.5mVrms.
HEADPHONES
digital voltmeter
(AC range)
oscilloscope
Connection points and Adjustment Location :
[ RX BOARD ] (Conductor side)
TX board (See page 4)
frequency counte
Adjustment Location :
Connection points and Adjustment Location :
TX board (See page 4)
– 3 – – 4 –
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