Maintenance; S-Meter Sensitivity; Equipment Required - Yaesu FT-902DM Instruction Manual
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Also See for FT-902DM:
- Instruction manual (57 pages) ,
- Survival manual (37 pages) ,
- Instruction manual (5 pages)
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MAINTENANCE
AND ALIGNMENT
WARNING
CAUTION
Never
operate
this
transceiver
in
the
transmit
mode
without a matched
antenna or dummy
load
connected
to the antenna
receptacle on
the rear
panel.
It is possible to damage
the final amplifier
tubes and the pi network components if the trans-
ceiver is operated
without
the proper load termi-
nation.
GENERAL
This
transceiver
has
been
carefully
aligned
and
tested
at
the
factory
and,
with
normal
usage,
should
not
require
other
than the usual attention
given
to electronic equipment.
Service or realign-
ment
of 4 major
component
may
require subse-
quent
realignment;
under
no
circumstances,
though,
should
realignment
be attempted
unless
the
operation
of the
transceiver
is fully under-
stood,
the
malfunction
has
been
carefully
ana-
lyzed, and the fault has definitely been traced to
misalignment.
Service
work
should
only
be per-
formed
by experienced
personnel using the proper
test equipment,
EQUIPMENT REQUIRED
(1)
RF Signal Generator:
Hewlett-Packard
Mode!
606A
or equivalent,
with
one
volt
output
at 50 Ohms,
and
frequency coverage
to 30
Mttz.
(2)
Vacuum
Tube Voltmeter (VTVM):
Hewlett-
Packard
Model
410B
or equivalent,
with an
RF probe good to 40 MHz.
(3)
Dummy
Load:
Yaesu model YP-150 or equiv-
alent, with 50 Ohm
non-reactive load imped-
ance rated to
[SO watts average power.
(5)
A general 'coverage
receiver covering
the fre-
quency
range
from
3 to 30 MHz with a 100
kHz calibrator
(6)
A frequency
counter,
Yaesu
Model
YC-500
or
equivalent,
with
resolution
to 0.01 KHz
and frequency coverage to 30 MHz
1.
S-METER SENSITIVITY
ADJUSTMENT
Place
the
transceiver
in the
receive
mode
and
connect a signal generator to the antenna terminal
of
the
transceiver.
Set
the
signal
generator
to
14200
kHz
with
an output
of 6 dB.
Tune
the
transceiver
to
14200
kHz for a maximum
reading
on
the S-meter.
The S-meter
should just start
to
rise with a 6 dB input, If no deflection is observed,
adjust
VRag>
to obtain
a slight meter deflection.
Apply
100
dB
input
to the
antenna
terminal;
the S-meter should
read S9 + 60 dB. If not, adjust
VRao,.
VRaoi
and
VRgo2
are
located
on
PB-
1704C
When
the transceiver is tuned
to 14200 kHz, the
100
kHz
calibrator
signal
will indicate
approxi-
mately
$9
+
10 dB
when
MARK
switch
is acti-
vated,
VRee
oOox
a 8
9
5 Ob 4
is)
IF unt
(PB-1704C)
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