I have a cx-366ce cb cannot hear talking what is wrong

if your radio has mic gain it may be that its turned up to high and it will cause feed back.

Check this Fixya thread about the same problem

probably sent enough power thru the reverse polarity diode to burd it but still have enough to keep lights on.

try screwing it back in

your power switch it faulty as there is a drop in voltage
does the meters dim down?? then the voltage supply past the power switch it dropping as it draws more current or... the audio ic has damage or one of its associated capactors sometimes a diode can become leeky its used for AM modulation also

Check cables and connectors.

• check antenna SWR,

A good SWR ranges from 1.2 to 1.5.

• check power output.

I would try an inline noise filter, the hum they are hearing is most likely vehicle electronic interference from alternator, etc. On my older Camaro I had the same hum in stereo and others heard it on CB, I installed noise filter and everything worked great. You can find them at truck stops, CB shops and some auto parts stores, they usually run in the $5-$10 range.

Hi,my name is John. Welcome to FixYa. Do you hear voice in radio? May be to close to each other. Let me know how it goes. Good luck and thanks for Choosing FixYa ..John sounds like feed back from speaker.

Hi, my name is John. Try turning your MIC-GAIN to MAX. Also have someone check the SWR on the antenna, Radio shack will do it for free or a CB Shack....hope this was helpful...

Here is the Owners Manual for the Connex CX-4300HP

http://www.cbtricks.com/radios/connex/cx4300hp/graphics/connex_4300hp_om.pdf