Icom IC-720 Instruction Manual page 31

contact your dealer or the nearest
—
Problem
ICOM Service Center.
Possible Cause
Solution
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1. Power does not come оп when
the switch is pushed.
speaker.
кене тен
2. Мо sound comes from the AF GAIN Control
Power cable is improperly connected.
Power cord is connected with the polarity
reversed.
Blown fuse.
C-PS15 MAIN switch is in the OFF position.
Carefully reconnect power cable.
Disconnect the power cord, replace the blown fuse,
then reconnect
the power cord observing proper
polarity.
Check for the cause, then replace the fuse with a
spare one.
If using an IC-PS15, also check it's fuse.
Place MAIN switch in ON position.
knob is completely
counterclockwise.
The unit is in the transmit mode, either by
the T/R switch or the PTT switch on the
microphone.
The external speaker cable is connected to
the unit but not to the external speaker jack
оп the power supply, or external speaker.
The internal speaker cable is not connected.
A headphone is connected to the PHONES
Jack.
3. Sensitivity is low and only strong
Signals are audible.
i a
Turn the knob clockwise to a suitable level.
Put the unit in the receive mode.
Connect the cable to the speaker jack on the
ІС-Р520, or external speaker.
Connect the speaker connection.
Unplug the headphone.
RF GAIN Control knob is turned fully
Counterclockwise.
The antenna feed line is cut or shorted.
The Attenuator is on.
Turn the RF Gain control knob fully clockwise.
Check the feed line and correct any improper
Turn the Atlenuator off.
4. During receive, the "5" meter is
higher than the 0" position
even when there is no signal.
6. The tone of the received signal
is very high or low pitched.
7. No output power or low output
power.
8. The receive mode functions
properly and your signals are
transmitted, but you are unable
to make contact with another
station.
RF GAIN Control
counter clockwise.
knob is turned fully
Turn the knob fully clockwise.
Maladjustment of the P.B. Tune control.
MIC GAIN setting is too low.
When SSB is desired, but the MODE switch
is in the CW or CW-N position.
PTT switch is not functioning due то
improper connection of the mic connector.
The antenna feed line is cut or shorted.
The SIMP/DUP Select is in the DU
tion.
The receive frequency is offset from the
transmit frequency by the RIT control.
P posi-
Set the P.B. Tune control knob to the clear tone
position.
Turn the MIC GAIN Contro! clockwise to the
center (12 o'clock) position.
Set the MODE switch to the SSB (USB or LSB)
position.
Using a screw driver, slightiy spread the prongs of
the mic connector for better contact.
Check the antenna feed line and correct any
improper connection.
Set the SIMP/DUP Select to the SIMP position.
Turn off the RIT, or set the RIT contro! knob to
the center (12 o'clock) position.
9. The right side of the unit case
becomes a little hot.
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10. The heat sink on the rear panel
becomes hot.
As the right side of the case is used as a heat
sink for the transmitter driver transistor,
even during normal operation, it may get as
hot as 35°C (63°F) above room tem-
perature.
The heat sink on the rear panel is for the
final transistors and may become as hot as
40°C (72°F) above room temperature.
Make sure that the area around the unit nas as
much ventilation as possible.
Make sure the area around the unit has as much
ventilation as possible.
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