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Without applying power to the line cord, turn the power switch ON and check the
position of the LINE VOLTAGE SELECTOR switch. All units are shipped with this
switch in the " 115 Volt" position. Adjust the selector switch so that the appropriate
voltage
is
indicated. ( If OPTIMOD-TV
is
installed within
a transmitter, 208/230V
may be
the only power available.) Check the fuse, and replace with the following
values if necessary:
110/115 VOLT:
1/2 amp SLO-BLO, 3AG-type ( as supplied);
208/230 VOLT:
1/4 amp SLO-BLO, 3AG-type.
AC
connection
to
the
chassis
is
made
through
an
RF
filter
with
IEC-standard
mains connector. This filter is designed to meet the standards of all international
electrical
safety
authorities,
and
leaks
less
than
0.5mA
to
the
chassis
when
operated from 230V mains.
A U.S.A.-standard " U- ground" power cord is supplied to connect to the IEC socket.
Users
in
other countries
should be
able to obtain
a power cord compatible with
their
country's standard. If you choose to cut the " U- Ground" plug from the cord
and replace it with a plug appropriate to your standards, refer to Fig. 3-1 below.
TYPE 18/3 SVT CORD, TYR -
(3 x .82 mm')
PLUG FOR
120 VAC
(USA)
CONDUCTOR
WIRE COLOR
Normal
All
L
LINE
BROWN
BLACK
N
NEUTRAL
BLUE
WHITE
E
EARTH GND
GREEN- YELLOW
GREEN
Fig. 3-1: POWER CORD COMPATIBILITY
Initialization
Options:
The
section
describes
how
to
change
certain
operating
characteristics of OPTIMOD-TV to suit your needs. If your needs correspond to the
"factory- standard" characteristics, then no modifications need to be made, and you
may skip to Reassembly below.
All
modifications
are
made
on
the
plug-in
circuit
cards.
If
the
steps
above
regarding
physical
inspection
have
been
followed,
the
cards
are
now
readily
accessible.
1)
Output Preemphasis: OPTIMOD-TV is shipped to provide a flat output, requiring
use
of the preemphasis network built into your aural exciter. As mentioned in
Exciters in Part 2 ( Applications), better peak control is obtained if the exciters
input
transformer,
preemphasis
network,
and
any
filtering
are
bypassed,
since
OPTIMOD-TV
can
provide
these
functions
with
greatly
improved
peak- control
accuracy.
Note
that
OPTIMOD-TV
is
shipped
with
either
75us
or
50us
internal
preemphasis, depending on government requirements in the Region to which it is
shipped unless ordered otherwise. Even if you are operating " flat" at the output,
the HF
limiter is still operating on the preemphasis curve, and a " flat" output
is
obtained by complementary deemphasis after the processing. Thus even with
"flat" operation, this internal preemphasis and deemphasis must complement that
used in the aural exciter.
Changing
preemphasis
is
non- trivial,
and
requires
changing
the
values
of
a
substantial
number
of
components.
If
you
wish
to
change
preemphasis,
please
consult the factory.
To
restrap for preemphasized output, move jumpers on Card # 7 according to
Fig.
3-2.
Card # 7 contains two active balanced output amplifiers ( for stereo);
thus, two jumpers must be moved.
3-2
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