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Maintenance And Toubleshooting; Common Questions; Engine Noise Suppression - Uniden UM423 AM Owner's Manual

Am marine radio
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Maintenance and Troubleshooting
Maintenance and Troubleshooting
Due to its rugged design, the UM423 AM requires very little maintenance.
However, it is a precision electronic instrument, so you should follow a few
If the antenna has been damaged, you should not transmit except in
the case of an emergency. A defective antenna may cause damage to
your radio.
You should arrange for periodic performance checks with your Uniden

Common questions

The radio won't power on.
The radio won't transmit.
Noise comes out of the speak-
er all the time
I can't hear anything (no vol-
ume) from the speaker.
I can't read the display.
The display is too bright at
Where can I find my radio's se-
rial number?

Engine Noise Suppression

Interference from the noise generated by the electrical systems of engines
is sometimes a problem with radios. The UM423 AM has been designed to
be essentially impervious to ignition noise and alternator noise. However, in
some installations it may be necessary to take measures to further reduce
the effect of noise interference. The UM423 AM radio DC battery wires,
antenna lead, and accessory cables should be routed away from the engine
and engine compartment, and from power cabling carrying high currents.
In severe cases of noise interference, it may be necessary to install a noise
suppression kit. Contact the dealer where you purchased the radio for more
Things to Try
Check the power connections.
Check the fuse.
Check the master battery switch and branch circuit
that connect to the radio.
Make sure the duration of each transmission is
less than 3 minutes.
Adjust the squelch level; it is probably too low.
Adjust the squelch level; it is probably too high.
Adjust the backlight brightness level (see page 16)
Adjust the backlight brightness level.
(see page 16)
Look on the bottom side of the radio



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