Receiver; Interstagetransformers; S-Metercalibration; Scannercenterstop - Yaesu FT-2500M Technical Supplement

r
Receiaer
Set
up the
test
equipment
as
shown below
for
receiver alignment.
Receiver
Alignment
Setup
Int
er st ag
e
Tr ansfo
r
mer
s
D
Connect the DC voltmeter between
J1003
pin
7
and chassis
ground.
O Modulate the
RF signal generator
with
t3.5
kHz deviation
of
a
1-kHz
tone.
tr
Adjust
T1001
-
TL004,
&
T1006
on the Main
Unit for maximum voltage
on the meter, then
once again
for
optimum SINAD (at least
-7
dBp for
12
dB SINAD).
S-Meter Calibration
D
\tVhile tuned
to
146.000
MHz,inject
a +25
dBp
RF
signal modulated
with
13.5
kHz deviation
of a
L-kHz tone, and adjust
VR2006
on
the
CNTL
Unit
so
that all
S-meter segments
are
just
on.
Scanner Center Stop
I
Connect
the DC voltmeter (3-V
range) be-
tween TP2002 (+) and TP2001(-) on the
CNTL
Unit.
tr
Withboth
the transceiver and signal generator
tune to
146.000
MH4
set
the
SQL
control
fully
counter-clockwise
(the "ausy" indicator
should be on). Lrject 20 dBp RF modulated
with t3.5 kHz
deviation
of al-kHz
tone, and
adjust VM007
on the CNTL
Unit for
0
V on the
voltmeter.
Squelch
D
Preset the SQL control to the
L0
o'clock posi-
tion.
At
the
center
of
the band, tune the
RF
signal generator to the same frequency, and set
the generator level to
-L2 dBp.
fl
Tum
VR1001 clockwise
until the squelch just
closes,
and then counter-clockwise very
slightly
so
that it just opens.
Receiver
Alignment
Points
T1001
T1002
T1003
r1004
r1
006
J1003
PinT
vR
1001
vR2007
rP2001 (
-
)
rP2002
(
+
)
vR2006
2-8
FT-2500M
Technical Supplement