Sony SRF-M100 User manual

SERVICE MANUAL
SRF-M100
AEP Model
SPECIFICATIONS
Frequency range
FM: 87.5 — 108 MHz 0.05 MHz*
AM: 531 — 1602 kHz
* The frequency display is raised or
lowered by steps of 0.1 MHz. (Example:
Frequency 88.05 MHz is displayed as
88.00 MHz.)
IF FM: 10.7 MHz
AM: 450 kHz
Speaker
4.4 cm (1 3/4 inches), 7.2 ohms
Output
Stereo earphones jack
(stereo ¢ 3.5mm, load impedance 16
ohms)
Power output
80 mW (at 10% harmonic distortion)
Power requirements
3 V DC, two R6 (size AA) batteries
Battery life (using Sony batteries SUM-3
(NS))
Earphones:
FM: Approx. 35 hours
AM: Approx. 45 hours
Speaker:
FM: Approx. 22 hours
AM: Approx. 26 hours
Dimensions
Approx. 121 x 72 x 27 mm (wih/d)
(4 7/8 x 2 7/8 1 1/8 inches) incl.
projecting parts and controls
Mass
Approx. 198 g (7.0 02.) incl. batteries
Supplied accessory
Stereo earphones (1)
Design and specifications are subject to
change without notice.
FM STEREO/AM PLL SYNTHESIZED RECEIVER
SONY.

TABLE OF CONTENTS
Section Title Page
Specifications eee ee ee eee eee ray ]
1. GENERAL
Location of Controls eee eee ee ee ee rr ey 3
Installing Batteries eee eee i ee iris 3
Setting the Clock eee eee ee ee ee eee ee ee ee i ee ee ee ir 4
Operating the Radio ee er er er ee rir 4
Preset Tuning ORD e eee meee ed memes eee ene eee eens eee eee eenesenensneeere 4
Sound the Beep at a Desired Time Cem e nme re cerns enanseceeesseureens 5
9. ‘DISASSEMBLY si essnseciessdce cents nai vvsen eatavactorsenaeeys 6
3. PIN DESCRIPTION: --:--cceeccesceccceeccsccscessceecescenecoeeees 7
4. ELECTRICAL ADJUSTMENTS -oeeesesseseeeeeeerseeeeeeereees 9
5. DIAGRAMS
5-1. Printed Wiring Boards <srrrrsseeessereeeeeeeeeeereeneeeneees 14
5-2. Schematic Diagram deem e mene n eer etennneee see eeeserenesenenes 17
6. EXPLODED VIEW iisicsecsnesecnsiaiieas shevecdeerceresnareanneans 21
7. ELECTRICAL PARTS LIST ---------eeesseersrereeeeeseee rene ae
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 conduc-
tor 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 damaged by heat.

SECTION 1
GENERAL
Front panel
Rear panel
Display window
(Ob.E
Reverv eye) meal ie cam A |
STEREO indicator
Lights when a stereo program is
received.
[2] Display window
Speaker
[4] ENTER/CLOCK button
[5] TIMER button
BAND selector
ALARM button
AUTO OFF/POWER switch
[9] VOLUME control
PRESET + and — buttons
PHONES (stereo earphones) jack
2
Earphones
Extend the earphone cord as it
serves as the FM antenna.
By disconnecting the earphone
cord, the sound is heard from the
speaker. The sound coming
through the speaker is monaural.
eIae)
STEREO/MONO (stereo/monaural)
selector .
TUNE (tuning)/TIME SET + and —
buttons
Battery compartment
Telescopic antenna
Extend the telescopic antenna as
illustrated.
Battery indicator
Flashes when the batteries become
weak,
Alarm indicator
Appears when you set the alarm.
Timer indicator
Appears when you set the timer.
Frequency indicator
Appears while the radio is on.
Band indicator
[22] PRESET and preset number
indicators
Time indicator
Appears when the radio is off.
This section is extracted from
instruction manual.
Two R6 (size AA) batteries with
correct polarity
Installing Batteries EJ
insert two R6 (size AA) batteries with correct polarity. When you insert the
batteries for the first time, 0:00 flashes in the display window. To stop flashing,
press ENTER/CLOCK.
Knowing when to replace the batteries
When the batteries become weak, the radio is turned off, the time indicator
appears and “cq” flashes in the display window. (The sound may become weak
or distorted before “‘csa” starts flashing.) Replace both batteries with new ones.
Even after you replace the batteries, “cosa” remains flashing. To turn off “cs”,
slide AUTO OFF/POWER.
Replace the batteries within about 60 seconds after turning off the power.
If more than 60 seconds has passed, the preset stations are canceled and the
time indicator shows 0:00.
In this case, perform the clock setting and preset tuning again.
Notes on the battery
¢ Insert the batteries with correct polarity.
* Do not mix new and used batteries.
e The batteries cannot be charged.
* To avoid damage from possible battery leakage, remove the batteries when the
unit will not be used for a long time.
* Concerning the battery life, see “Specifications”.
Se ET

Setting the Clock
When you set the clock, turn off the radio.
1 While keeping ENTER/CLOCK pressed, press
TUNE/TIME SET + or — button until the
display shows the current time.
Press + to increase or — to decrease the
digits. When you keep the button pressed,
the digits change rapidly.
While setting the
time, “:" is flashing. 0:00 = midnight
12:00 = noon
2 When the display shows the current time,
release ENTER/CLOCK.
“?" stops flashing and the clock starts
operating.
To set the clock to the second
After adjusting the time, keep ENTER/CLOCK
pressed. Release ENTER/CLOCK using the
time signal as a reference.
eee ule Mm UC Mteleom D | 2
1 While pressing the green button, slide AUTO
’ OFF/POWER to the direction of the A mark
to turn on the power.
2 Select FM or AM with BAND.
3 Tune in the desired station by pressing
TUNE/TIME SET + or — button.
At each press of + or —, the FM frequency
changes by 0.05 MHz higher or lower (the
display changes by 0.1 MHz) and the AM
frequency changes by 9 kHz higher or lower.
To change the frequency rapidly, keep the
button pressed.
4 Adjust VOLUME.
To turn off the radio
Slide AUTO OFF/POWER again.
The display shows the current time.
When the power is turned off automatically
The radio will be turned off automatically after
about 90 minutes to prevent unnecessary wear
of the batteries. To continue listening to the
radio, slide AUTO OFF/POWER again. If the
batteries are exhausted, the power is turned
off automatically to protect the preset
contents.
To receive a stereo program in stereo
Use the earphones. The sound coming through
the speaker is monaural.
Preset Tuning
Once you store the desired stations, you can tune them in by a simple operation. You can store
7 stations for each of the FM and AM bands.
Presetting the Station [4
1 Turn on the power.
2 Tune in the desired station to preset.
See “Operating the Radio”. .
3 Keep ENTER/ICLOCK pressed for more than
1 second.
Release ENTER/CLOCK when PRESET and
the preset number indicator flash in the
display window with the beep sound.
4 Select a preset number from 1 to 7 by
pressing the PRESET + or — button.
Press + to increase the digit.
(12>... . +67)
to
Press — to decrease the digit.
(7>6—>. .. . -*2->1)
| eae ee ee
5 Press ENTER/CLOCK again.
Beep-beep sounds, and PRESET and the
preset number stop flashing.
The station has been stored.
To preset other stations, repeat steps 2 to 5.
Note
Go to the next step while the PRESET and
preset number are flashing (for about 5
seconds). Otherwise the unit returns to step 2.
If this happens, try again from step 3.
Tuning in a Preset Station jj
1 Turn on the power.
2 Select the band, FM or AM.
3 Select the desired preset number by pressing
the PRESET + or — button.
4 Adjust VOLUME.
To change the preset station
Tune in the desired station to be newly preset.
Preset the tuned station to the desired button.
The station previously preset to that button is
canceled.
To Improve Radio Reception
FM: Extend the telescopic antenna and adjust
the angle of the antenna so that the FM
sensitivity will be increased.
AM: A ferrite bar antenna is built in for AM
reception. Rotate the unit horizontally for
optimum reception.
If the FM stereo program is noisy
Usually set STEREO/MONO to STEREO. You
can receive the FM stereo program in stereo,
using the earphones. When the signal is
weak and noisy, set it to MONO. There will
be no stereo effect, but the sound will
improve.

Sounding the Beep at a Desired Time
You
can
make
the
unit
sound
its
beep
through
the
speaker
or
the
earphones
at
a
desired
time.
Use
this
feature
to
remind
you
of
an appointment,
etc.
There are two ways of setting:
¢
Timer
setting—to
sound
the
beep
a
certain
number
of
minutes
later
than
the
present.
e
Alarm
setting—to
sound
the
beep
at
a
certain
time.
You
can
set
the
timer
and
alarm
while
the
radio
is
either
on
or
off.
Setting the Timer [ej
1 While keeping TIMER pressed, press
TUNE/TIME SET + or— button to store the
desired period in minutes after which you
want the beep to sound.
You can store periods from 1 to 180 minutes
at one minute intervals.
&) flashes in the display window while you
press TIMER. To sound the beep after 30
minutes, for example, while keeping TIMER
pressed, press TUNE/TIME SET + or — until
30 appears in the display window.
2 Release TIMER.
©) stops flashing.
The display returns to the current time or to
the frequency which was shown before you
- pressed TIMER to start the timer setting.
When the stored period has passed, )
flashes and the beep sounds. :
To cancel the timer setting
Press TIMER again. &) disappears.
To stop the beep
Press any button.
If you do not stop the beep, the beep stops
automatically after about 3 minutes.
When the beep sounds while you are fistening
to the radio, the radio reception stops and
resumes when the beep stops.
Setting the Alarm [J]
Make sure that the clock is correctly set. (See
“Setting the Clock”.)
1 White keeping ALARM pressed, press
TUNE/TIME SET + or — button to set the
time you want the beep to sound.
) flashes while you press ALARM.
To set the alarm for 7:00 in the morning, for
example, while keeping ALARM pressed,
press TUNE/TIME + or — until 7:00 appears
in the display window.
2 Release ALARM.
*) stops flashing. The display returns to the
current time or the frequency which was
shown before you pressed ALARM to start
the alarm setting.
When the time comes, () flashes and the
beep sounds.
To cancel the alarm setting
Press ALARM again. () disappears.
To stop the beep
Press any button.
If you do not stop the beep, the beep stops
automatically after about 3 minutes.
When the beep sounds while you are listening
to the radio, the radio reception stops and
resumes when the beep stops.
Notes
e When 0:00 flashes, you cannot set the alarm.
e When you stop the beep, the timer setting is
canceled. The alarm setting remains.
* Even if you are listening to radio, you can
set the timer and alarm.

SECTION 2
DISASSEMBLY
Note
:
Follow
the
disassembly
procedure
in
the
numerical
order
given.
2-1.
CABINET
(REAR)
2-3.
MAIN
BOARD
4+B2
x
8
@
+82x6
ees
x
Battery
case
¢
7
@+B2x8
™%
:
é
}
f
PEA
©
Cabinet
(Rear)
‘
as
© Press the tab as
YY shown by the arrow.
i N
aS
© Insert a flat-tipped screwdriver in the
groove
between
the
front
cabinet
and
,
4)
Pies
ie
tab
es
SHOW
Dy
Meow,
the rear cabinet to open.
2-2.
CABINET
(FRONT)
2-4.
MICROCOMPUTER
BOARD
@ +826
-
@
+82
x6
Microcomputer
board
@ Press the tab as
shown by the arrow.

SECTION 3
PIN DESCRIPTION
Pin description of 4 PD1724GB-555-1A7 (IC101)
LCD drive segment signal output.
Pin
number
-[2
pe >)
ea
—
Mm __ ON
APN owo re
i bdo
LCD drive common signal output
— be
—_ al
VSS3
CAP2
CAP1
CGP BUZZER
16
Terminals
used
for
connecting
a
capacitor
of
a
doubler
circuit
which
supplies
LCD
17
drive
voltage.
18
VSS2
Audio
mute
output
signal.
Active
when
Low.
Audio
noises
are
reduced
before
and
after
the
mute
signal
when
PLL,
radio
power
supply
or
key
srtobe
change
is
controlled.
Buzzer
output
using
CGP.
Sound
to
check
keys,
to
check
settings,
to
indicate
that
a
setting
time
of
timer
is
reached
or
to
alarm
is
produced
by
using
two
kinds
of
musical
intervals
and
the sound
modulation.
nN Oo
pels!
ie)
D D
VCOH VHF
VCOM FM VCO
25 VCOL AM VCO
26 VSS1 VSS1
27
EOI
EO1
Ea
Not
use
with
this
machine.
28 EO2 EQ2
5V power supply input terminal.
NY 0
<
i)
23
24
Detects
the
voltage
reduction
of
the
AC
battery.
When
the
battery
energy
is
reduced,
the
microcomputer
is
in
the
reducedvoltage
mode.
The
battery
mark
blinks
and
the
microcomputer
waits
for
a
clock’s
reset/display
and
Power
ON
Key.
A quartz oscillating element connecting terminal. (75kHz)
Connected
to a
capacitor
for
a
regulator
circuit
which
supplies
the
oscillator’
stable
drive voltage.
Time
display
switching
input.
It
is
a
24-hour
system
display
when
Low
and
a
12-hour
system
display
(AM/PM)
when
High.
When
the
setting
is
changed,
backup
power
supply
must
be
set
to
OFF
and
internal
RAM
must
be
initialized.
ON/OFF switching output for the radio power supply.
(ON : High , OFF : LOW)
Strobe output for initial switch input.
INIT OUT (Active : High)
o——+ INITIN 1: 12-/24-hour system display
LOW (OFF) : 24-hour system display,
Hgih (ON) : 12-hour system dispaly
o——»> INIT IN 2: Band selection
Not use with this machine.
pe
o
ies)
le
eg
30
31 XI
XO
32 VSS4 VSS4
x
He
‘
OO Ww
Ww
PA3 INIT IN1
Qo
KR
PA2 POWER OUT
nS
PAI INIT OUT

number
1-bit input which sets two kinds of receiving band versions. When the setting is
36 PAO INIT IN2 I changed, backup power supply must be set to OFF and internal RAM must be
initialized.
Cas [i
BEEP Vol BEEP volume. Output for increasing the volume of the BEEP sound when a setting
time of timer is reached or an alarm is ON. The volume is increased when high.
ten aca (50 ct ane ER
Pap
Pe
Key SOURCE
a
K3
7 | Key RETURN I
48 KO
1-bit output which sets two kinds of receiving bands. Two settings are as followes.
AM=H, FM=L, POWER OFF : L
Strobe and return signals in 3 X 4 key matrix. A strobe signal change makes an
audio noise. A strobe signal must be set to the fixed value when a key input is not
changed. When the key input is decoded, the mute signal must be added.

SECTION 4
ELECTRICAL ADJUSTMENTS
©
Be
sure
to
perform
a
AM
tracking
adjustment
after
having
made
a
AM
frequency
coverage
adjustment.
Setting:
BAND SW : AM
STEREO /MONO SW : MONO
AM PF signal
generator
Put the jead-wire
VA antenna close to
the set.
Cd
Phones jack
30% amplitude modulation by 400Hz
Signal.
Output level : as low as possible.
AM IF Adjustment
Procedure :
1. Set the frequency of the set and RF SSG at 531 KHz.
2. Adjust T1 so that the reading of VTVM becomes
maximum.
3. Refer to the diagram below for the final characteristics.
ae
(final characteristics)
T1
{MAIN BOARD (Conductor side)] {MAIN BOARD (Component side))
digital
voltmeter
AM
Frequency
Coverage
Adjustment
AM
Tracking
Adjustment
Procedure
:
Procedure
:
1.
Set
the
frequency
of
the
set
and
RF
SSG
at
531kHz.
1,
Set
the
frequency
of
the
set
and
RF
SSG
at
585kHz.
2.
Adjust
LS
so
that
the
voltage
between
TP4
and
the
2.
Adjust
L1
so
that
the
reading
of
VTVM
becomes
ground
becomes
|
+
0.05V.
maximum.
3.
Set
the
frequency
of
the
set
and
RF
SSG
at
1,602kHz.
3.
Set
the
frequency
of
the
set
and
RF
SSG
at
1,485kHz.
4,
Adjust
CT3
so
that
the
voltage
between
TP4
and
the
4.
Adjust
CT1
so
that
the
reading
of
VTVM
becomes
ground
becomes
7.3
+
0.05V.
maximum.
5.
Repeat
the
adjusting
steps
above
two
or
three
times.
@
Terminate
the
AM
tracking
adjustment
by
adjusting
the
trimmer capacitor.

@ Be sure to perform a FM tracking adjustment after having
FM Frequency coverage and Taking Adjustment
Setting:
BAND SW : FM
STEREO /MONO SW : MONO
VTVM
FM PF signal
generator
Phones jack
(CJ
22.5kHz, frequency deviation by
400 Hz signal.
Output level : as low possible
digital
voltmeter
(MAIN BOARD (Component side)]
FM Frequency Coverage Adjustment
Procedure :
1. Set the frequency of the set and RF SSG at 108.0MHz.
2. Adjust L4 so that the voltage between TP4 and the
ground becomes 9.5 + 1.5V.
made a FM frequency coverage adjustment.
(MAIN BOARD (Conductor side)]
FM Tracking Adjustment
Procedure :
1. Set the frequency of the set and RF SSG at 87.5MHz.
2. Adjust L2 so that the reading of VTVM becomes
maximum.
3. Set the frequency of the set and RF SSG at 108.0MHz.
4, Adjust CT2 so that the reading of VTVM becomes
maximum.
5. Repeat the adjusting steps above two or three times.
@ Terminate the FM tracking adjustment by adjusting the
trimmer capacitor.