Maintenance; Troubleshooting - Icom IC-78 Instruction Manual

Troubleshooting

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The following chart is designed to help you correct
problems which are not equipment malfunctions.
PROBLEM
Power does not come
on when the [PWR]
switch is pushed.
No sounds comes out
of the speaker.
Sensitivity is too low,
and only strong signals
are heard.
Received audio is
unclear or distorted.
Your signal does not
reach as far as usual.
Transmit signal is
unclear or distorted.
The displayed channel
does not properly
change.
POSSIBLE CAUSE
• Power cable is improperly connected.
• Fuse is blown.
• Volume level is set too low.
• The squelch is closed.
• The transceiver is transmitting.
• The antenna is not properly connected.
• The antenna is not properly matched to
the operating frequency.
• The wrong tuner value is selected in set
mode.
• The attenuator is activated.
• The wrong mode is selected.
• The noise blanker is turned ON when
receiving a strong signal.
• The [RIT] control is rotated too far
clockwise, or counterclockwise.
• The antenna tuner is not matched to the
operating frequency when manual tuning
is selected.
• The CW or RTTY mode is selected for
voice transmission.
• The wrong mode is selected.
• Microphone is too close to your mouth.
• The dial lock function is activated.
• The Quick Set mode is selected.

MAINTENANCE

If you are not able to locate the cause of the problem,
or solve it through the use of this chart, contact your
nearest Icom dealer or Service Center.
SOLUTION
• Reconnect the DC power cable correctly.
• Check for the cause, then replace the fuse
with a rated one.
( Fuses are installed in the DC power cable
and the internal PA unit.)
• Rotate [AF] clockwise to obtain a suitable
listening level.
• Turn [RF/SQL] to the position that just
opens the squelch.
• Check the SEND line of an external unit.
• Reconnect to the antenna connector.
• Push [TUNE] to tune the connected
antenna tuner.
• Set the proper value for the connected
tuner.
• Push [ATT] to turn the attenuator OFF.
• Push [MODE] to select the proper
operating mode.
• Push [NB] to turn the noise blanker OFF.
• Adjust the [RIT] control to receive proper
audio output.
• Push [TUNE] to tune the external antenna
tuner.
• Push [MODE] to select USB, LSB, or AM
mode.
• Push [MODE] to select the proper
operating mode.
• Speak into the microphone at your normal
voice level. Hold the mic farther away from
your mouth.
• Push [LOCK] to turn the Lock function
OFF.
• Push [SET] to exit the Quick Set mode.
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