92
13
MAINTENANCE
■
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.
The IC-7400 has 2 types of fuses installed for trans-
ceiver protection.
• DC power cable fuses ................................ FGB 30 A
• Circuitry fuse ................................................ FGB 5 A
D
D
DC power cable fuse replacement
Refer the figure illustrated at right for the DC power
cable fuse replacement.
D
D
Circuitry fuse replacement
The 13.8 V DC from the DC power cable is applied to
all units in the IC-7400, 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. 89.
w
Remove the 11 screws from the PA shielding plate,
then remove the plate.
e
Replace the circuitry fuse as shown in the diagram
at right.
r
Replace the PA shielding plate and top cover.
■
Tuning dial brake adjustment
The tension of the tuning dial may be adjusted to suit
your preference.
The brake adjustment screw is located on the right
side of the tuning dial. See the figure at right.
Turn the brake adjustment screw clockwise or counter-
clockwise to obtain a comfortable tension level while
turning the dial continuously and evenly in one direction.
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/SPCH] to turn the function OFF.
• Push [MENU] several times to exit the set
mode.
• Reset the CPU.
p. 52
—
p. 93
30 A
fuse
Fuse
CAUTION:
DISCONNECT
the DC power cable
from the transceiver when changing a fuse.
Light
Heavy
IC-7400.qxd 02.4.2 11:36 Page 92