Sony ICF-7800 - SECTION 3 ADJUSTMENTS - AM; AM Section Alignment Procedures

FM 1F ALIGNMENT (with 10.7 MHz Sweep Generator)
Setting:
sweep generator
(center freq.: 10.7 MHz)
ae
main board — conductor side —
oscilloscope
V (DC) H (AC)
main board — conductor side — Adjust the vertical position to
center the sweep base-line.
Procedure:
1. Adjust the sweep range of the generator so that 3. Turn the secondary core (ORG) of IFT F1 to
the
full
width
of
the
response
curve
appears
on
obtain
the
maximum
noise
level
as
shown
the
oscilloscope.
below.
2. Turn the primary core (BLU) of IFT F1 to
position the response curve in center as shown
below.
noise level
center response curve
Note: The responce curve is changed up and
down only.
ICF-7800
_ICF-7800
3-2. AM SECTION
SW
AM rf signal
generator
30% amplitude
modulation by
400 Hz signal
MW
AM rf signal
generator
Ni Put the lead wire
antenna close to
O the set.
30% amplitude
modulation by
400 H2 signal
Note: e Repeat the procedures in each adjustment
several times, and the frequency coverage and
tracking adjustments should be finally done by
the trimmer capacitors.
e After adjusting the SW frequency coverage and
tracking adjustments perform the MW adjust-
ments.
MW TRACKING ADJUSTMENT
Adjust for a maximum reading
on VOM).
1,400 kHz 600 kHz
AM IF ALIGNMENT
Adjust for a maximum reading
on VOM (i).
468 kHz
1,680 kHz 520 kHz
Adjust for a maximum reading
on VOM (4).
MW FREQUENCY COVERAGE
ADJUSTMENT
@
*Ge¢
main board — conductor side —
VOM ()
(range: 0.5—5V ac}
EARPHONE
SW TRACKING ADJUSTMENT
Adjust for a maximum reading
on VOM ® ‘
12.3MHz
ne = = 7 | 3.8MHz | MHz
SW FREQUENCY COVERAGE
ADJUSTMENT
Adjust for a maximum reading
on VOM ® $
6
12.3 MHz
3.8 MHz
i