Sony TMRRF-975-R Service manual
TMR-RF975R
SERVICE MANUAL
Ver 1.1 2001. 06
TMR-RF975R is the component model block one in the MDR-RF975RK.
COMPONENT MODEL NAME FOR MDR-RF975RK
Headphones MDR-RF975R
Transmitter TMR-RF975R
US Model
SPECIFICATIONS
General
Carrier frequency
913.5 – 914.5 MHz
Channel Ch1, Ch2, Ch3
Modulation FM stereo
Frequency response
18 – 22,000 Hz
Transmitter TMR-RF975R
Power source DC 9 V: supplied AC power adaptor
Audio input phono jacks/stereo mini jack
Dimensions Approx. 130 135 150 mm
Mass Approx. 200 g (7 oz.)
Design and specifications are subject to change without
notice.
1
(5
/4 5 3/8 6 in.) (w/h/d)
XX
XX
9-873-140-12
2001F0200-1
© 2001.6
TRANSMITTER
Sony Corporation
Personal Audio Company
Shinagawa Tec Service Manual Production Group
TMR-RF975R
TABLE OF CONTENTS
Specifications ............................................................................ 1
1. GENERAL ....................................................................... 2
2. DISASSEMBLY
2-1. Housing (Upper) ....................................................... 3
2-2. TX-BASE Board ....................................................... 3
3. ELECTRICAL ADJUSTMENTS ............................. 4
4. DIAGRAMS
4-1. Block Diagrams ........................................................ 5
4-2. Schematic Diagram– TX-BASE Section – ............... 6
4-3. Printed Wiring Board – TX-BASE Section – .......... 7
4-4. Schematic Diagram
– BATTERY CHARGER Section – .......................... 8
4-5. Printed Wiring Board
– BATTERY CHARGER Section – .......................... 9
5. EXPLODED VIEWS....................................................10
6. ELECTRICAL PARTS LIST.....................................11
SECTION 1
GENERAL
This section is extracted from
instruction manual.
Setting up the
transmitter
Connect the transmitter to audio/video
1
equipment. Select one of the hookups
below depending on the jack type:
To connect to a headphones jack
A
Transmitter
OFF ON
FILTERNOISE
BA
R
AUDIO IN
DC IN 9V
L
to AUDIO IN
A jacks
123
CHANNEL
Right channel
(red)
Connecting cord
(supplied)
Unimatch plug
adaptor
(supplied)
to headphones
jack (stereo
phone jack)
Flexible Circuit Board Repairing
• Keep the temperature of 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
or unsoldering.
Left channel
(white)
to headphones
jack (stereo
mini jack)
Discman, MD,
WALKMAN*, VCR,
etc.
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.
2
SECTION 2
)
)
Housing (upper)
2
CHG-NR board
1
Four screws (P 2
× 6)
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given .
2-1. HOUSING (UPPER)
TMR-RF975R
2
Housing (upper)
1
Four screws (P 2
× 8
2-2. TX-BASE BOARD
Housing (upper)
Screw
3
TX-BASE board
1
Screw (P 2
2-3. CHG-NR BOARD
2
× 6
3
TMR-RF975R
SECTION 3
ELECTRICAL ADJUSTMENTS
Setting :
AF signal
generator
set
TMR-RF975R
L-CH / R-CH (J402)
Telescopic
antenna
Frequency counter
8 cm
set
TMR-RF975R
Transmission Frequency Check
1. Set the noise filter SW to OFF.
2. Input a signal of 1 kHz, 40 mVrms to only the L-CH (J402).
3. Connect a telescopic antenna to the frequency counter input
and extend the antenna to a length of approximately 8 cm.
4. Place TX-BASE board close to the frequency counter, then
measure the frequencies of CH1, CH2 and CH3 and make
sure the values are as follows:
CH1 : 913.5 MHz ± 200 kHz
CH2 : 914.0 MHz ± 200 kHz
CH3 : 914.5 MHz ± 200 kHz
When the frequency does not satisfy the specified value,
set the channel switch (S402) to CH2, then adjust the value of
the frequency counter to 914.0 MHz by trimmer capacitor in
the VCO unit.
Standard value :913.9MHz to 914.1MHz.
Pilot Signal and MPX Signal Modulation Check and
Adjustment
1. Set the channel to CH2.
2. An electric wave is output for 5 or 10 minutes when OFF to ON
a power supply with no signal input (Power indicator will ON).
3. Set the RV402 and RV403 to max. (clockwise)
4. Connect a digital voltmeter (AC range) to the center terminal
of RV403 (Fig.2).
5. Adjust the value of the digital voltmeter to minimum by RV401.
6. See the RV402 to minimum. (counter clock wise)
7. Adjust the value of the digital voltmeter to max by L407.
8. Adjust the value of the digital voltmerter to 2.1to 2.6mVrms
by RV403.
9. Connect a digital voltmeter (AC range) with LPF to movable
terminal of RV403 (Fig.2).
10. Input a signal of 1 kHz, 316 mVrms to only the L-CH.
11. Adjust the value of the digital voltmeter to 5.2 to 6.4 mVrms
by RV402.
Connection points and Adjustment Location :
CH3
L407
←
CH2 ←CH1
S402
RV403RV402
(L-CH) (R-CH)
R464
J402
Sheet
VCO
UNIT
CHG-NR board
When completed with replacement, recheck the frequecies of
CH1, CH2 and CH3.
Compresser Output Check
1. Set the channel to CH2.
2. Input a signal of 1 kHz, 316 mVrms to L-CH and R-CH of
J402.
3. Measure IC 601 pin 7 and IC 602 pin 7 on the CHG-NR
board using a digital voltmeter (AC range) and put down a
value mesured. (Fig.1).
4. Input a signal of 1 kHz, 31.6 mVrms to L-CH and R-CH of
J402.
5. Measure IC 601 pin 7 and IC 602 pin 7 on the CHG-NR
board using a digital voltmeter (AC range) and put down a
value mesured (Fig.1).
Confirm that there is a difference of step 3 and 5 by 10dB±
3dB.
6. When the frequency is not satisfied the specified value,
exchange TX- BASE board or CHG-NR board.
RV401-403,
L407
Modulation
check and
adjustment.
digital
voltmeter
(AC range)
R464
(Fig. 2)
RV401
+
–
Hole
Trimmer capacitor:
Transmission
frequency
adjustment
digital
voltmeter
(AC range)
(Fig. 1)
+
–
1
4
IC 601
7 pin
IC 602
8
5
8
1
5
4
4
4-1. BLOCK DIAGRAMS
SECTION 4
DIAGRAMS
TMR-RF975R
B
AUDIO IN
A
TX-BASE BOARD
J401
R-CH
J402
L
R R-CH
S401
NOISE FILTER
OFF
|
ON
NOISE
FILTER
CHG-NR BOARD
IC401
IC601
(L-CH)
IC602
(R-CH)
RV401
CH1
AMP
CH2
AMP
MODULATION
12 11
TIME
DEVISION
MPX
BUFFER
OSC
AMP
76
X401
38kHz
BUFFER
Q401
10
VS
BUFFER
DIVIDER
D404,405
RECT
2V
D408
RV402
9
MODULATION
L407
8
MODULATION
B+
5V
Q402,405
INPUT
DET
Q403
MODULATION
CHANNEL
SET
Q408
RV403
MODULATION
1
2
3
I
S402
CHANNEL
MOD IN
VCO401
(VCO UNIT)
ANT
ANT401
O
IC402
V
5V
+5V
REG
D401
power
SWITCH
Q404
POWER
ON/OFF
Q406,407
CHG-NR BOARD
SWITCH
Q601
IC604(1/2)
DETECT
IC603
D407
SWITCH
Q602
D402
chg
SWITCH
Q604
COMPARATOR
(2/2)
OSC
Q605
IC605
+5V
REG
IC604(2/2)
DETECT
SWITCH
Q603
REF V
+
CHARGE
TERMINAL
–
(TO MDR-RF975R)
J404
DC IN 9V
(1/2)
IC403
STEREO MPX
LPF
R-CH
14
1
72113
• R-ch is omitted due to same as L-ch.
• Signal path.
L : AUDI O
F : FM
5
5
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