Sony SRF-M55 User manual

Ver 1.0 1999.09
MICROFILM
SRF-M55
SERVICE MANUAL
FM STEREO PLL SYNTHESIZED RADIO
SPECIFICATIONS
AEP Model
E Model
Chinese Model

– 2 –
Specifications ........................................................................... 1
1. GENERAL
Location and Function of Controls .................................... 2
2. DISASSEMBLY
2-1. “Cabinet ASSY, Front”, “Cabinet ASSY, Rear” ......... 3
2-2. Main Board ................................................................. 3
2-3. LCD201 ...................................................................... 4
2-4. Microcomputer Board................................................. 4
3. ADJUSTMENTS .......................................................... 5
4. DIAGRAMS
4-1. Explanation of IC Terminals....................................... 6
4-2. Block Diagrams .......................................................... 7
4-3. Printed Wiring Boards .............................................. 10
4-4. Schematic Diagram................................................... 13
5. EXPLODEDVIEW..................................................... 17
6. ELECTRICAL PARTS LIST.................................... 18
Flexible Circuit Board Repairing
• Keep the temperature of the 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.
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
TABLE OF CONTENTS
SECTION 1
GENERAL
LOCATION AND FUNCTION OF CONTROLS

– 3 –
SECTION 2
DISASSEMBLY
Note : Follow the disassembly procedure in the numerical order given.
2-1.“CABINET ASSY, FRONT”,“CABINET ASSY, REAR”
2-2. MAIN BOARD
rThe equipment can be removed using the following procedure.
Cabinet ASSY, Front
Cabinet ASSY, Rear
Set Main board
Microcomputer board
LCD201
1 Screws (B1.7x8)
2 Claws
2 Claws
3
4
Flexible board
(10 core)
5 LCD flexible board (13 core)
Cabinet ASSY, rear
Cabinet ASSY, front
2 Claw
3 Claw
4
1
2
Main board
Cabinet ASSY, front
Button (power)
Lid, battery case
3 Claw

– 4 –
2-3. LCD201
2-4. MICROCOMPUTER BOARD
1 Claws
2
Cabinet ASSY, fron
t
LCD201
1 Screws (1.4)
3
5
Cabinet ASSY, rear
4 Claw
4 Claws
2 Claws
Microcomputer board
Cover, side

– 5 –
FM STEREO (19kHz) Adjustment
Setting :
Procedure :
1. Connect the frequency counter to TP (19kHz).
2. Turn the set to 98MHz.
3. Adjust RV1 for 19kHz reading frequency counter.
Standard Value : 18.9 –19.1kHz
Connection:
SECTION 3
ADJUSTMENTS
FM Section
Setting :
Connection:
For FM frequency coverage adjustment
• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
FM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1 10.7MHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
CT2 87.5MHz adjustment value: 2V
standard value: 1.5 – 2.5V
Confirm 108.0MHz standard value: 9 – 13V
FMTRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
CT1 98MHz
FM RF signal
generator
22.5kHz frequency deviation by
400Hz signal.
Output level : as low as possible
TP (ANT)
0.01
µ F
set
16
Ω
headphones jack EP1 ( i )
level mete
r
FM RF signal
generator
Carrier frequency : 98MHz
Modulation : 1kHz, 22.5kHz deviation
Output level : 1mV (more than 60dB)
TP (ANT)
0.01
µ F
1-676-002-
C
C101
C102
R106
R105 R109
R119
R120
R111
R107
R102
R108
R101
R104
R103
R
C103 C124
C105
C104
C125
Q
CF1
BPF101
CF2
D101
D102
BE
C
BCE
Q104
Q101
Q105
ECB
TP
(ANT)
TP
(LPF)
digital
voltmeter
TP
(ANT)
[MAIN BOARD]
(SIDE A)
TP (LPF)
1
5
13
15
20
24
10
12
IC101
C114 C115
C113
C
109
C
108
R121
R115
1
12 R113 R114
C111
C110
C107 C116
C112
CF3
TP
(19kHz)
frequency counte
r
TP (19kHz)
1
µ F/50V
[MAIN BOARD] (SIDE A)
0 dB=1µV
Adjustments Location :
CT2 : FM Frequency Coverage
Adjustment
CT1 : FM Tracking Adjustment
T1 : FM IF Adjustment
RV1 : FM Stereo (19kHz) Adjustmen
t
[MAIN BOARD] (SIDE A)

– 6 –
SECTION 4
DIAGRAMS
4-1. EXPLANATION OF ICTERMINALS
IC301 µPD17015GS-556-GJG (SYSTEM CONTROL, LCD DRIVE)
Pin No. Pin name I/O Description
1 POB2 I Key return input.
2 PCO0 O Key source output.
3 PCO1 O Key source output.
4 PCO2 I Power (AUTO OFF) key input.
5 PCO3 I HOLD key input.
6 POD0/BEEP O Beep output.
7 POA0 I Key return input (Fixed at “L”).
8 POA1 I Voltage decrease information input. E: On-and-off
9 POA2 O Power ON/OFF output. “H” : ON
10 POA3 O Mute signal output. “H” : Mute ON
11 CE I Voltage decrease information input. E: Lighting
12 XOUT O System clock output (75 kHz).
13 XIN I System clock input (75 kHz).
14 VDD — Power supply.
15 GND — Ground.
16 EO O PLL error output.
17 VREG O Voltage regulator output.
18 VCOH I FM VCO input.
19 VCOL — Not used (OPEN).
20 – 28 LCD 0 – 8 O LCD segment output.
29 – 32 COM 0 – 3 O LCD common output.
33 VLCD1 — Power supply for LCD drive.
34 CAP1 — Connecting pins of the capacitor for LCD drive voltage.
35 CAP0
36 VLCD0 — Power supply for LCD drive.
37 POB0 I Key return input.
38 POB1

– 7 – – 9 –– 8 –
SRF-M55
• Signal path.
F: FM
4-2. BLOCK DIAGRAMS

23 4 5 6 7 89 10 11 12
A
1
B
C
D
E
F
G
02
[MICROCOMPUTER BOARD]
(SIDE B)
[MICROCOMPUTER BOARD]
(SIDE A) [MAIN BOARD] (SIDE B) [MAIN BOARD] (SIDE A)
11
(11)
1-676-003- 11
(11)
1-676-003-
11
(11)
1-676-002- 11
(11)
1-676-002-
C302
C326
C320
C321
C316
C318
C323
C317
C203
R332
R301
R321
R334
R306
R316
R317
R311
R310
R309
R312
R204
R202
R302
R304
R331
R330
R333
R305
R318
R303
R319 R320
R313
R308
R307
R203
R205
C206
R206
R201
C324
C305
C303
C304
C327
C328
C311
C315
C314
C319
C202
C204
C205
S202
POWER
(AUTO OFF)
S201
HOLD
S203
MODE
1
2
4
3
12
43
IC201
12
45
3
IC302
IC202
C201
X201
CN201
CN202
1
1
5
10
510
13
LCD201
LIQUID
CRYSTAL
DISPLAY
S205(JOG)
1
5
10
15
19 20
25
30
35
36
IC301
ECB ECB
Q305Q304
C312 C313
L304
D301
D306
D305
D303
C329
L303
T301
C301
Q301 Q307
ECB
Q308
ECB
BE
C
Q306
Q310
RV2
\VOL\∑
C27
C5 C6
C29
C26
C1 C18
C23
C22
C9
C21
C20
R9
R30
R3
R2
R1
R5
R4
R8 R99
C10
R98 R97 R96
C24
C16
C17
C8
C7
C19
C15
C13
C14
C25
C11
L4
1
56
10
IC3
157
14 10 8
IC2
C2
C28
C4
C12
L3
L1
RV1
T1
CT1
S1
S2
S1
FM SENS
DX
LOCAL
S2
GROOVE
MEGA BASS
OFF
CT2
L2
1
45
8
IC1
CN1
1
510
DRY BATTERY
SIZE "AAA"
(IEC DESIGNATION R03)
1PC, 1.5V
EP1
2
C120
C119 C122
C121
R118
R116 R117
R123
R122
C123
L5
L7
L6
BE C
Q103
1
5
13
15
20
24
10
12
IC101
C114 C115
C113
C109 C108
C106
C101
C102
R106
R105 R109
R119
R121
R115
R124
R120
R111
R107
R102
R108
R101
R104
R103
R110
R112 R113 R114
C103 C124
C105
C104
C111
C125
C110
C107 C116
C112
BCE
Q102
CF1
CF3
BPF101
CF2
D101
D102
BE
C
BCE
Q104
Q101
Q105
ECB
TP
(ANT)
TP
(19kHz)
TP
(LPF)
S202
-1
-2
BATT2
LITHIUM
BATTERY
BCE
– 10 – – 12 –– 11 –
SRF-M55 4-3. PRINTEDWIRING BOARDS
Note on Printed Wiring Boards:
Note:
•X: parts extracted from the component side.
•r:Through hole.
•b: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
Caution:
Pattern face side: Parts on the pattern face side seen from the
(Side B) pattern face are indicated.
Parts face side: Parts on the parts face side seen from the
(Side A) parts face are indicated.
D101 F-11
D102 F-11
D301 F-4
D303 F-4
D305 D-5
D306 D-5
IC1 F-8
IC2 D-8
IC3 C-5
IC101 E-12
IC201 D-3
IC202 D-3
IC301 C-5
IC302 E-5
Q101 F-12
Q102 E-11
Q103 B-12
Q104 G-12
Q105 G-12
Q301 G-5
Q304 D-4
Q305 D-4
Q306 F-5
Q307 G-5
Q308 F-5
Q310 F-5
Ref. No. Location
rSemiconductor
Location
Note on Schematic Diagram:
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.
•U: B+ Line.
•H: adjustment for repair.
• Power voltageis dc 1.5V and fedwith regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : FM
• Voltages aretaken with aVOM(Inputimpedance10 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: FM

– 13 – – 15 –– 14 –
SRF-M55
4-4. SCHEMATIC DIAGRAM
rWAVEFORMS
1
Q301-2 C
2
3
4
VOLT/DIV : 1 V AC
TIME/DIV : 0.1 µsec
T301
IC301 qs
XOUT
IC302 5
VOLT/DIV : 1 V AC
TIME/DIV : 0.2 µsec
VOLT/DIV : 0.1 V AC
TIME/DIV : 5 µsec
VOLT/DIV : 0.5 V AC
TIME/DIV : 5 µsec
4.6Vp-p
360 nsec
5.2Vp-p
982 nsec
330mVp-
p
75kHz
2.9 Vp-p
21
µ sec
rRefer to page 10 for Notes. rRefer to page 16 for IC Block Diagrams.