38
7
INSTALLATION AND CONNECTIONS
n CR-338 high stability crystal unit
By installing the CR-338, the total frequency stability
of the transceiver will be improved.
q Remove the bottom cover as shown in the previous
diagram.
w Disconnect W2 from J4401 (MAIN unit) and W3
from J4201 (MAIN unit).
e Remove 9 screws from the PLL unit, disconnect
P4 from J201 (MAIN unit) and P2 from J401 (MAIN
unit), then remove the PLL unit.
r Remove the supplied internal crystal and replace
with the CR-338.
t Return the PLL unit, plugs and flat cables to their
original positions.
y Adjust the reference frequency at C16 using a fre-
quency counter if desired.
• Connect the frequency counter to P 2 (PLL unit).
u Return the bottom cover to its original position.
CR-338
PLL unit
Internal crystal
W 3
W 2
J 4201
J 4401
P 4
J 201
J 401
P 2; Frequency check point
(Connect a frequency counter
and adjust the frequency to
64.00000 MHz with C 16.)
C 16
MAIN unit
PLL unit
n Optional IF filters
Several IF filters are available for the IC-78. You can
install 1 filter for 455 kHz IF. Choose the appropriate
filter for your operating needs. (pgs, 21, 22)
D Installation
q Remove the bottom cover as shown on the p. 48.
w Remove 7 screws, connection cable P1 from J1, P5
from J701, W4 from J4101 and W5 from J4001 and
2 Tr-clampers as shown in the diagram below.
e Install the de-
sired 455 kHz
filter as shown
in the diagram
at right.
r Mount the fil-
ter with the sup-
plied washers
and nuts.
t Solder the 4
leads.
y R e t u r n t h e
MAIN unit and
bottom cover to
their original po-
sitions.
After filter installation, specify the installed filter
using initial set mode. (p. 33) Otherwise, the in-
stalled filter will not function properly.
J 701
P1
P5
W4
Tr-clamper
Tr-clamper
MAIN unit
J4101
J1
W5
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