Can I use an external mic? - JVC Everio GZ-HM650 Camcorder

Just plugging in the external mike into the jack should AUTOMATICALLY disconnect the internal mike.

probably use a external mic with a USB connection

have you tried plugging in an external mic?
If it works with an external mic, chances r that the issue is not hardware, but configuration within your operating system

The built-in mic is actually always enabled. It only gets disabled once you connect an external mic just as you have done. Disabling it disables the mic capability which means that it also disables your external mic capability. If you have any problem with the built-in mic being on all the time you could try to go to the volume controller and mute it from there. The downside here is that you would actually need to unmute it each time you use your external mic.

The mic output on the ua-4fx only supplies 5mA of power. If your mic reqires more than that, then it won't work. Consider an external mic preamp.

-William

check external mic in another system.
update the bios of the sytem.
update drivers of sound cards

on page 49 of your owner's manual, the operation of the mic input switches is described.

Your external mic needs to have a 1/8" plug. You will need to find the "Mic" input, this is generally found behind a removable or hinged plastic or rubber panel, and usually near the A/V plug connectors. When you plug in an external mic, the camera switches over to use it rather than the built-in mic. On this camcorder, you cannot set the recording level of the external mic. The camera sets the level automatically. So it is simply a plug-and-play, or plug-and-record solution.

Using an external mic allows you to reduce self-noise and handling noise. It is generally recommended for better videos. Different microphones are likely to interact in different ways with your camera and its automatic level-setting, so you should try out different microphones if you have more than one available to you.

If you put the camcorder in manual mode, there is a microphone sensor that will move when sound is picked up by the external microphone. In manual you can keep everything else automatic. The off for the mic means that the built in mic is turned off when an external mic is attached.

Check mic connections