Maintenance - Icom IC-718 Basic Manual

9

MAINTENANCE

D Troubleshooting
The following chart is designed to help you correct problems which are not equipment malfunctions.
If you are not able to locate the cause of a problem or solve it through the use of this chart, contact your nearest
Icom Dealer or Service Center.
Problem
Power does not turn
ON when [PWR] is
pushed.
No sound is heard
from the speaker.
Sensitivity is too low,
and only strong signals
are heard.
Receive audio is
distorted.
Cannot transmit.
Output power is too
low.
Cannot contact with
another station.
Transmitted signal is
distorted.
Programmed scan
does not stop.
Programmed scan
does not start.
Memory scan does not
start.
The displayed
frequency does not
change when rotating
the main dial.
D Replacing the circuitry fuse
The 13.8 V DC from the DC power source is applied to all units in the IC-718 through the circuitry fuse.
The fuse is in the MAIN unit.
1. Remove the top cover of the
transceiver. (1)
2. Replace the circuitry fuse to a
brand-new one. (2)
3. Replace the top cover.
24
Possible cause
• DC power cable is improperly connected.
• Fuse is blown.
• The external power supply is turned OFF.
• The audio level is too low.
• The squelch is closed.
• The transceiver is in the transmitting
mode.
• The Antenna is not properly connected.
• The antenna for another band is
connected.
• The antenna is not properly tuned.
• The attenuator is activated.
• The operating mode is not selected
correctly.
• The IF SHIFT function is activated.
• The Noise blanker function is activated.
• The preamp is activated.
• For the USA version, Noise Reduction
function is activated and set too high.
• The operating frequency is outside the
selected ham band.
• RF power is too low.
• The microphone gain is too low.
• The selected antenna is for a different band.
• The antenna is not properly tuned.
• The RIT function is activated.
• The Split frequency function is activated.
• The microphone gain is too high.
• The microphone compressor function is
activated.
• Squelch is open.
• [RF/SQL] is assigned to RF gain control
and squelch is open.
• The same frequencies have been entered
in scan edge memory channels P1 and
P2.
• 2 or more memory channels have not
been entered.
• The dial lock function is activated.
• A Quick Set mode screen is selected.
• The internal CPU has malfunctioned.
1
Solution
• Properly reconnect the DC power cable.
• Turn ON the external power supply.
• Find and repair the cause of the problem, and then
replace the blown fuse with a new one.
• Rotate [AF] control clockwise to obtain a suitable
listening level.
• Rotate [RF/SQL] to around the 10 o'clock position to
open the squelch, and adjust the squelch level.
• Turn off the transmit mode.
• Reconnect the antenna connector.
• Connect an antenna suitable for the operating band.
• Hold down [TUNER] for 2 seconds to manually tune
the antenna.
• Turn OFF the Attenuator.
• Select the correct operating mode.
• Rotate [SHIFT] to the center position.
• Push [NB] to turn OFF the function.
• Push [P.AMP] to turn OFF the function.
• Set the [NR] control for maximum readability.
• Set the frequency within the selected ham band.
• Set [RF POWER] to a suitable level.
• Set [MIC GAIN] to a suitable level.
• Select an antenna suitable for the operating frequency.
• Hold down [TUNER].
• Push [RIT] to turn OFF the function.
• Push [SPLIT] to turn OFF the function.
• Set [MIC GAIN] to a suitable level.
• Push [COMP] to turn OFF the Microphone
compressor function.
• Set [RF/SQL] to the threshold point.
• Reset [RF/SQL] control assigned and set it to the
threshold point.
• Enter different frequencies in Scan Edge memory
channels P1 and P2.
• Enter 2 or more memory channels.
• Push [LOCK] to deactivate the function.
• Push [SET] to exit the Quick Set mode.
• Reset the CPU.
2
Ref.
p. 6
p. 6
p. 6
p. 7
p. 10
–
p. 5
p. 3
p. 11
p. 8
p. 12
p. 11
p. 11
p. 15
p. 9
p. 10
p. 10
–
p. 1
p. 11
p. 15
p. 10
p. 16
p. 10
p. 10
p. 17
p. 17
p. 9
p. 18
p. 7
Circuitry fuse
(FGB 4A)