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– 9 –

– 10 –

 Follow the disassembly procedure in the numerical order given.

1

Helical antenna

1

4

3

3

3

Battery case lid

Cabinet (Rear) assy

2

 Screws 

2

 Screws

Claw

Claws

Claws

– 11 –

7

 Remove solder

9

 CN401 (16pin)

IF board

Coaxial connector

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!£

!™

!º

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8

!º

!™

!º

RF board

Chassis

Cabinet (Front) assy

Microcomputer board

IF board

RF board

5

 Screws 

5

 Screws 

2

 Remove solder

1

 Knob (VOL)

4

6

3

 CN402 (22pin)

– 12 –

The ICF-SC1 and SC1PC have a scan-stop function used to scan
for the correct frequency.
Scanning continues until the squelch turns off (when a signal is
received). However, just setting the squelch off as condition does
not guarantee that  the scan-stop function will always stop at the
correct frequency. (It might for instance deviate 1 step to an adja-
cent frequency.)
So scan-stop is set to trigger only at the correct frequency, by check-
ing the DC voltage component (S-curve voltage) of the FM detec-
tor output.
The DC voltage component of the FM detector output may vary
however, due to variations in the parts components of the FM de-
tector circuit or deviations in the local oscillator frequency. There-
fore, once repair or alignment is complete, read the DC voltage
component of the RF detector output while it is input with an IF
signal from a signal generator, and use that value as a reference to
write data on the EEPROM.
Two types of writing are performed on the EEPROM since there
are two types of FM detectors.

WFM

n for WFM

NFM

n for NFM, AM

Refer to the following for information on the write method and on
the signal input method using a signal generator.

All LCD lamps up when the three [EXE], [–] and [SCAN] keys are
simultaneously held down while the power is off.

1. Input method for S-Curve voltage component read mode
Simultaneously hold down the [MODE], [STEP] and [BAND] keys
for at least 1second while power is off.
The set (ICF-SC1/SC1PC) power turns on and a display as shown
below appears.

2. Quitting S-Curve voltage read mode
Press the [POWER] button.

When set in S-Curve voltage read mode, do not connect any-
thing to the antenna terminal while the power to the RF sec-
tion is on. (An unwanted signal might otherwise be received
through the antenna.)

However when set, a check can be made that a broadcast RF carrier
wave was received.
(1) Turn the power on as usual and receive a broadcast signal.
(2) Turn off the power and set in read mode with [MODE] + [STEP]

+ [BAND].

(3) Write can be checked with [SVC] or [SCAN] since the broad

cast signal received in (1) can be heard.

In the following cases the message “TRY AGAIN” appears and
writing is disabled.
(1) When the Squelch is closed.
(2) When the S-curve voltage that was read, is not within 0.5V to

1.3V.

Signal input method using signal generator.
1. In NFM

(1) Connect a signal generator to TP1 by way of a 0.01

µ

F capaci-

tor.

(2) Receive NFM (Receive frequency does no matter)
(3) Input 455kHz from the signal generator, 90 to 100dB

µ

, modu-

lation 30%, mod frequency of 1kHz.

(4) Write the COMPN terminal voltage onto the ROM.
(5) Press the [SVC] button.

When data is written, a display as shown below appears.

2. In WFM

(1) Connect a signal generator to TP4 by way of a 0.01

µ

F capaci-

tor.

(2) Receive WFM (Receive frequency does no matter)
(3) Input 10.7MHz from the signal generator, 90 to 100dB

µ

, fre-

quency deviation 22.5kHz, mod frequency of 1kHz.

(4) Write the COMPW terminal voltage onto the ROM.
(5) Press the [SCAN] button.

When data is written, a display as shown below appears.

16

0.01

µ

C407

1000P

MIX

IN

IC401

TA31136FN

45M X'tal filter

TP1

S.G.

10

0.01

µ

S.G.

C434

0.01

µ

FM RF

IN

IC402

CXA1111N

RF BOARD

TP4

NFM       

0 . 9 4

Voltage (V)

WFM

0 . 8 7

Voltage (V)

[ IF BOARD] (Rear side)

CN402

COMPN 

COMPW