lost of incoming or outgoing transmision

[vstyn]

I have unidne um425 marine radio, and after it warms up, i don't get no sound ( either squelch or voice.)

 

[RadioRon]

Do you get any sound at any time? To troubleshoot the cause, you will have to check various things one-by-one to see what section or component is not working properly. There are many ways to go about this, and it is a good idea to understand how the radio should work. Always investigate the DC power supply sections first. Does the radio receive DC power and does that power get past the ON/OFF switch, the fuses and power filters? Are the internal DC regulators working and can you see bias voltage to the various sections of the radio?

Have a look at this page:
https://electronics.stackexchange.com/questions/39419/how-to-diagnose-and-repair-a-radio