JRC NDR-91 User Manual

(3)
When
it is
conflnned that
the receiver
RF input filter
circuit CFL-184
andlor
itself
is bad, replace
the BK
relay
of
the receiver,
RF
AMP
CAF-I9I.
6.3.2 No
sound
The sound
does not
come through
the
speaker
even
though
the
speaker
is connected
to
the
receiver
correctly,
and no defects
have
been
found
in the
speaker
and indications
of the
receiver.
In
such a case,
check the receiver
in the following
procedures.
Checking
procedure
(
I
)
Rernove
the
E!!&TE
connector from
the receiver.
If
the sound colnes out
through
the
speaker,
-tsK
is
grounded
somewhere
in the
BK
line.
Check
wirings of otherreceivers,
transmitters
and
consoles
to
which
-BK
line
is
connected
in
parallel.
(2)
Lock-out check
of the
synthesizer
Take
out the receiver
liom
the
cabinet
case or rack,
and check
LEDs from
the
top after
turning on
the
power.
LEDs
can be visually
checked
through
the hole
on
the top
cover
of the receiver.
If LED
are off,
it
is correct. But
if
LED light,
the
synthesizer
is locked
out. But the following
case is
not
abnormal condition:
After
changing
the receiver
frequency,
LED light until the
synthesizer
is locked.
6.3.3
Noise and beat
Even though changing the receiving
frequency
band,
noise or
beat
sound comes
through
the speaker. But that
noise is evidently
not external
noise.
Especially,
in case of
small ship,
many
kinds
of
electronic equipments
are concentrated
in the
small
room,
so
that
the
mutual
interference
may happen
among
equipments.
In many
cases, the receiver
suffers intert-erence.
When
the mutual
interference
arises,
search
the
surrounding
for
the source
of
noise. Especially,
when
mounting
a new electronic
equipment,
you
must check
whether the new equipment
gives
the noise
interference
to the receiver
or
not.
Checking
procedure
(
I
)
Investigation of the
source of noise
At
first,
set the
receiver
to
such a condition
where the
noise
comes out
through
the
speaker.
Turn ofT the
power
of the equipments
other than
the receiver
successively. If
the noise
stops
when turning off the
power
of some equipment,
it
is considered
that the
equipment is the source
of
the noise.
Sometimes,
the
power
supply
itself may
generate
the high
frequetrcy noise,
not the
electronic
erluipment.
In
such
a
case, use
the
other
power
supply line.
(2)
Investigation of the
route of
noise
After
checking the noise source, the
route
of the noise must
be investigated.
The
noise
routes
are
largely
classified as
shown in the figure.
*2t-

JRC NDR-91 Specifications

General

Brand	JRC
Model	NDR-91
Category	Receiver
Language	English