SRF-R405
Tourist Model
SERVICE MANUAL
FM STEREO/AM PLL SYNTHESIZED RADIO
MICROFILM
SPECIFICATIONS
Frequency range
Band
Frequency range
Channel step
FM
76 108 MHz
0.1 MHz
AM
530 1,710 kHz
9 kHz/10 kHz
Speaker
Approx.2.8 cm (11/8 inches) dia., 7.2
Output
2 (headphone) jack
(
3.5 mm, stereominijack)
Power output
80 mW (at 10% harmonic distortion)
Power requirements
3 V, DC two R03 (size AAA) batteries
Power Auto Off function
Approx.30 minutes, 60 minutes,
90 minutes,120 minutes, and off
Dimensions Approx. 55
× 98 × 17 mm(w/h/d)
(21/4
× 37/8 × 11/16 inches) not incl.
projecting parts and controls
Approx. 59.2
× 98.2 × 17.8 mm(w/h/d)
(23/8
× 37/8 × 23/32 inches) incl.
projecting parts and controls
Mass
Approx. 89 g (3.1 oz) incl. batteries
Accessories Batteries (2)
Carrying case (1)
Design and specifications are subject to change
without notice.
Ver 1.0 1999. 04
-- 2 --
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.
SECTION 1
GENERAL
This section is extracted
from instruction manual.
-- 3 --
SECTION 2
DISASSEMBLY
2-1.
CABINET (REAR) ASSY
Note :
Follow the disassembly procedure in the numerical order given.
Note :
On installation of cabinet (rear), adjust the knob (earphone/speaker) and switch positions until they agree.
1 Open the lid, battery case
7 Cabinet (rear) assy
6 Open the cabinet from
the recessed areas.
(Remove the 9 claws.)
Claws
Claws
Claws
Knob (EAR/SP)
Switch
Claws
3 Open the lid, ear-phone
2 Screw (M1.7
× 5)
4 Screw (M1.7
× 5)
5 Screw (M1.4
× 10)
2-2.
MAIN BOARD
Note :
On installation of cabinet (rear), adjust the knob (earphone/speaker) and switch positions until they agree.
4 Screw (B1.4
× 6)
5 Claw
Switch
1 Knob(HOLD)
7 Button(NOISE CUT)
8 Spring compression
6 Main board
2 Remove two solders
of terminal, battery.
3 Remove two solders
of speaker leads.
-- 4 --
SECTION 3
ELECTRICAL ADJUSTMENTS
[FM]
Setting
ENT/BAND switch : FM
Signal generator
[AM]
Setting
ENT/BAND switch : AM
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L202
76.0MHz
CT202
108.0MHz
TUNER SECTION
AM VCO ADJUSTMENT
Adjust so that the voltage at TP3(LPF) becomes 2.60 ±0.05V.
L205
531kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L201
585kHz
CT201
1,485kHz
0 dB = 1 µV
· Repeat the procedures in each adjustment several times for a
maximum reading on level meter, and the frequency coverage
and tracking adjustments should be finally done by the trimmer
capacitors.
Adjustment Location :
MAIN board (side A)
MAIN board (side B)
TP3 (LPF) TP1 (ANT)
TP4
(76kHz)
L202, CT202
FM Tracking Adjustment
L201, CT201
AM Tracking Adjustment
RV301
FM STEREO (76kHz)
Adjustment
L205
AM VCO Adjustment
T201
AM IF
Adjustment
22.5 kHz frequency
deviation by
400 Hz signal 30%
Output level : as low as possible
FM RF signal
generator
Set
0.01
µF
TP1(ANT)
Level meter
Headphones jack
(J401)
MAIN board
16
AM RF signal
generator
Put the lead-wire
antenna close
to the set.
Set
Headphones jack
(J401)
MAIN board
TP3(LPF)
Digital
Volt meter
Level meter
16
30% amplitude
modulation by
400 Hz signal
Output level : as low as possible
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T201
450kHz
FM STEREO (76kHz) ADJUSTMENT
Adjustment point
Frequency Indication
Frequency counter Reading
RV301
FM76MHz
76kHz ±200Hz
FM STEREO (76kHz)
Procedure :
1. Connect frequency counter to the positions shown below.
2. Tune the set to 76MHz.
0.01
µF
FM RF SSG
to TP1(ANT)
Carrier frequency : 76MHz
Modulation : no modulation
Output level : 0.1V (100dB)
Frequency counter
0.01
µF
+
TP4(76kHz)
Use a frequency counter
having input impedance
of 10M
or higher.
SECTION 4
DIAGRAMS
4-1. BLOCK DIAGRAM
3
B+ (+1.2V)
B+ (+1.2V)
D201-2
D201-3
L205
AM VCO
L202
L204
B+ (+1.2V)
B+ (+1.2V)
CT201
CT202
L201
AM FERRIT-ROD
ANTENNA
D201-1
D202
AM TRACKING
FM TRACKING
AM RF IN
AM OSC
AM FE
10
12
14
13
6
16
19
23
28
29
58
3
7
8
9
10
11
26
27
13
14
15
22
61
4
60
FM RF IN
7
FM RF
5
4
FM OSC
FM FE
D203
AFC
FMAM
FE OUT
FM VCO
AMP
Q201
B+
(+1.2V)
T201
AM IF
15
21
1
1
4
4
2
10
9
1
8
7
23
4
14
15
2
CF203
CF202
CF201
BAND
SELECT SWITCH
Q203
1.2V REG
SWITCH
Q202
TUNING,
MUTE SWITCH
Q204
MUTE
Q401
AM IF IN
BAND SELECT
FM IF IN
VOLTAGE
DETECT
IC505
2.9V REG
Q507
REG SWITCH
Q508
3V REG
Q603,604
DET OUT
VCC
NF2
FM
DISCRI
FM
DISCRIMINATOR
FM IF
AM IF
DET AGC
TUNING
METER
REG OUT
METER
NOISE CUT
BUFFER
Q305,
Q306(2/2)
NORMAL
BUFFER
Q303,304
R-CH
R-CH
S501
C
HOLD
ON
OFF
PLL LOW-PASS
FILTER
Q501,502
SW
S502-512
SYSTEM CONTROL
LIQUID CRYSTAL
DISPLAY
DRIVE
IC506
(NOISE CUT) P0B0
BAND
VCOL
XOUT
XIN
(HOLD) INT
P0A1 TV 4-12CH
P1B0 KS0
P1B1 KS1
P1B2 KS2
P1B3 KS3
P1A0 KR0
P1A1 KR1
P1A2 KR2
P1A3 KR3
EO
BEEP
17
POC1
35
36
37
39
40
|
44
46
|
53
55
56
COM0-3
LCD0-14
VDD
VDD
18
VDET2
6
P0A3 POWER
57
(VDET1) CE
P0A2 MUTE
FM/AM FRONT END
IC201
B+
(+3V)
RV401
VOL
VOLTAGE
DETECT
IC503
TV (4-12CH)
3V REG
Q103
DC/DC CONVERTER
T601, Q601,602
LIQUID
CRYSTAL
DISPLAY
BATT2
LITHIUM
BATTERY
PAS621L
B+
(+3V)
B+
(+3V)
DRY BATTERY
SIZE "AA"
(IEC DESIGNATION R03)
2PCS, 3V
(SPEAKER)
(EAR-RECEIVER)
SP101
(SPEAKER)
HP101
(EAR-RECEIVER)
S401
EAR-RECEIVER
/SPEAKER
J401
2
16
X701
75kHz
B+
(TV+3V)
· Signal path
:FM
:AM
TP1
ANT
8
Q306(1/2)
ANALOG SWITCH
Q307
DECODER
SYNC DET
VCO
VCO STOP
FF
0°
FF 1/2
STEREO
SWITCH
PHASE
COMPARETE
LAMP
TRIGGER
FF
90°
EP/SP
SWITCH
Q301,302
LOUT
ROUT
PRE+POWER2
VOL
REG
EP
SP
RV301
FM DECODER
IC301
POWER AMP
IC401
TP2
VCOL
TP9
CE
TP4
B+
TP4
76kHz
TP19
DET
TP18
D/D CON
L201, CT201
L202, CT202
FM STEREO (76kHz)
-- 5 --
-- 6 --