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108
15
MAINTENANCE
■
Fuse replacement
If a fuse blows or the transceiver stops functioning, try
to
fi
nd the source of the problem, and replace the dam-
aged fuse with a new, rated fuse.
CAUTION:
DISCONNECT
the DC power cable
from the transceiver when changing a fuse.
The IC-756PROIII has 2 types of fuses installed for
transceiver protection.
• DC power cable fuses ................................ FGB 30 A
• Circuitry fuse ................................................ FGB 5 A
DC POWER CABLE FUSE REPLACEMENT
30 A
fuse
■
Clock backup battery replacement
The transceiver has a lithium backup battery
(CR2032) inside for clock and timer functions. The
usual life of the backup battery is approximately 2
years.
When the backup battery is exhausted, the trans-
ceiver transmits and receives normally but cannot re-
tain the current time.
See p. 106 for battery location.
CIRCUITRY FUSE REPLACEMENT
The 13.8 V DC from the DC power cable is conver
ted to 5 V or 8 V and applied to all units in the IC-
756PROIII, except for the power amplifier, through
the circuitry fuse. This fuse is installed in the PA unit.
q
Remove the top cover as shown on p. 105.
w
Remove 11 screws from the PA shielding plate,
then remove the plate.
e
Replace the circuitry fuse as shown in the diagram
below.
r
Replace the PA shielding plate and top cover.
Circuitry fuse (FGB 5 A)
PROBLEM
POSSIBLE CAUSE
SOLUTION
REF.
DISPLA
Y
The displayed frequency
does not change properly.
• The dial lock function is activated.
• A set mode screen is selected.
• The internal CPU has malfunctioned.
• Push
[LOCK/SPEECH]
to turn the function OFF.
• Push
[EXIT/SET]
several times to exit the set
mode screen.
• Reset the CPU.
p. 65
pgs. 10,
94
p. 21
15