Fuse Replacement; Clock Backup Battery Replacement - Icom IC-756PRO Instruction Manual

PROBLEM
The displayed frequency
does not change properly.

Fuse replacement

If a fuse blows or the transceiver stops functioning, try
to find 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-756PRO has 2 types of fuses installed for
transceiver protection.
• DC power cable fuses ................................ FGB 30 A
• Circuitry fuse ................................................ FGB 5 A
CIRCUITRY FUSE REPLACEMENT
The 13.8 V DC from the DC power cable is applied to
all units in the IC-756PRO, except for the power am-
plifier, through the circuitry fuse. This fuse is installed
in the PA unit.
q Remove the top cover as shown on p. 73.
w Remove 11 screws from the PA shielding plate,
then remove the plate.

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. 77 for battery location.
POSSIBLE CAUSE
• The dial lock function is activated.
• A set mode screen is selected.
• The internal CPU has malfunctioned.
SOLUTION
• Push [LOCK] to deactivate the function.
• Push [EXIT] one or more times to exit the set
mode screen.
• Reset the CPU.
DC POWER CABLE FUSE REPLACEMENT
30 A
fuse
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)
CR2032
11
MAINTENANCE
REF.
p. 6
pgs.
11, 64
p. 22
75