Sony ICFC-900-HS Service manual
ICF-C900HS
SERVICE MANUAL
Ver 1.0 1998. 07
SPECIFICATIONS
US Model
Canadian Model
E Model
MICROFILM
FM/AM CLOCK RADIO/
HOME SECURITY LIGHT
CONTROL SYSTEM
TABLE OF CONTENTS
3
1. GENERAL .................................................................. 3
2. DISASSEMBLY ......................................................... 4
3. ELECTRICAL ADJUSTMENTS ........................ 6
4. DIAGRAMS ................................................................ 8
4-1. Block Diagram ................................................................ 8
4-2. Printed Wiring Boards..................................................... 10
4-3. Schematic Diagram ......................................................... 13
4-4. IC Pin Function Description ........................................... 17
HOW TO CHANGED THE CERAMIC FILTERS
This model is used two ceramic filters of CF1 and CF3.
You must used same type of color marked ceramic filters in order
to meet same specifications.
Therefore, the ceramic filter must changed two pieces together
since it’s supply two pieces in one package as a spare parts.
Mark Center frequency
CF
mark
red 10.70 MHz
blue 10.67 MHz
orange 10.73 MHz
5. EXPLODED VIEWS ................................................ 19
6. ELECTRICAL PARTS LIST ............................... 21
CF1
black 10.64 MHz
white 10.76 MHz
SAFETY CHECK-OUT
After correcting the original service problem, perform the following safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs,
screws, and all other exposed metal parts for AC leakage.
Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester , such as the Simpson 229 or RCA
WT -540A. Follo w the manufacturers’ instructions to use these
instruments.
2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The “limit” indication is 0.75 V, so analog meters must have an accurate lowvoltage scale. The Simpson 250 and Sanwa SH-63Trd are examples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V A C range are suitable. (See Fig. A)
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE
WITH MARK ! ON THE SCHEMATIC DIAGRAMS AND IN
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL
OR IN SUPPLEMENTS PUBLISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS P AR UNE MARQ UE ! SUR
LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES
PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE
FONCTIONNEMENT . NE REMPLACER CES COM- POSANTS
QUE PAR DES PIÈCES SONY DONT LES NUMÉROS SONT
DONNÉS DANS CE MANUEL OU D ANS LES SUPPLÉMENTS
PUBLIÉS PAR SONY.
– 2 –
To Exposed Metal
Parts on Set
1.5 k
0.15 µF
Fig. A. Using an AC voltmeter to check AC leakage.
Ω
Earth Ground
AC
voltmeter
(0.75 V)
SECTION 1
GENERAL
This section is extracted from
instruction manual.
– 3 –
SECTION 2
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
CABINET (UPPER) SECTION
2
knob (alarm)
3
cabinet (upper) section
MAIN/SWITCH BOARD
4
SWITCH board
3
two claws
2
holder (transformer)
1
two screws
(BTP3
×
20)
1
two flat wire
(CN1, 3)
1
speaker wire
(CN1)
1
three screws
(BTP3
7
×
20)
6
battery snap
MAIN board
5
three claws
– 4 –
a
1
pointer
2
3
6
three claws
4
knob (tuning)
When installing, knob (tuning) adjust the
marking (B) hole and pointer boss.
5
Turn variable capacitor
(CV1) shaft and
knob (tuning) in the
arrow direction fully.
boss
B
7
MAIN board
variable capacitor
(CV1)
knob (tuning)
marking (B) hole
TRANSFORMER (T102)
2
1
transformer (T102)
power cord
Note: When installing, position the power coad as shown in the figure.
power cord
FM wire antenn
DIAL POINTER SETING
Note: Follow the assembly procedure in the numerical order given.
– 5 –
SECTION 3
r
r
e
ELECTRICAL ADJUSTMENTS
TUNER SECTION
[FM]
Setting:
BAND switch: FM
FM RF signal
generator
0.01 µF
400 Hz, 30% FM modulation
frequency deviation
Output level: as low as possible
±
22.5 kHz
MAIN board
TP (FMIN)
[AM]
Setting:
BAND switch: AM
AM RF signal
generator
400 Hz, 30%
AM modulation
Output level: as low as possible
MAIN board
TP (SP-OUT)
• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L3 86.5 MHz
CT1-3 109.5 MHz
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L2 86.5 MHz
CT1-2 109.5 MHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L4 520 kHz
CT1-4 1,650 kHz
Put the lead-wire
antenna close to
the set.
level mete
8
Ω
+
–
DATA TX SECTION
DATA TRANSMISSION LEVEL ADJUST
Setting:
RANDOM switch: OFF
AC outlet
set
measure
terminal
filter unit
AC120 V, 60 Hz
AC voltmete
+
–
Schematic Diagrams of the filter unit:
AC outlet
0.1µF
62
11
Ω
Ω
measur
terminal
1 mH
1 mH
0.1
µ
F
Adjusting Procedure:
1. Insert the AC plug of set into the A C Outlet of filter unit while
pressing [D.S.TSUMMERT], [CLOCK],
[SNOOZE/DATE/SLEEPOFF] buttons simultaneously.
2. All LCD segment are turned on, and the test mode will start.
3. Press all button one by one as below,
[D.S.TSUMMERT], [CLOCK], [TIMESET–], [TIMESET+]
[ALARMA], [ALARMB], [LIGHT1], [LIGHT2]
[SNOOZE/DATE/SLEEPOFF], [RADIOOFF,ALARMSET]
[RADIOON,SLEEP]
4. Set [RANDOM] Switch to OFF n ON n OFF position, and
the display “OFF TIME0*” are appear.
5. Press [1] button to blink the display “OFF TIME*” and the
carrier signal output continuity,
(*: ID code No.)
6. Adjust T2 to 0.45 V observing AC voltmeter.
Adjustment V alue:
Adjustment part STANDARD VALUE
T2 0.35 V to 0.55 V
7. To exit from test mode, disconnect the power cord of set.
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 600 kHz
CT1-1 1,400 kHz
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1 455 kHz
– 6 –
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