When a microphone stops recording there are a few things to check. The first thing to check is the cable you are using to connect the camera and microphone. The camera only works with TRS 3.5mm diameter stereo mic jacks. The easiest way to tell what kind of mic jack it is to look at the number of silver rings on the jack. If it only has one it is the correct cable with a TRS jack, if it has two it is the incorrect cable with a TRRS jack.
The next thing to look at is how the cable is plugged into the microphone and camera. It needs to be pushed in all the way so that the rubber part of the jack is flush with the microphone and camera. If it is unplugged even a little bit it can cause the microphone not to pick up.
The last thing to check is related to the audio recording settings on the camera and the internal microphone. With the camera in movie mode, and the microphone unplugged, press the menu button and go to the first page under the red camera tab. Select Sound Recording. On the next page there will be a sound meter at the bottom of the screen. Check to see if the sound levels move without the microphone plugged in.
If they don't that is an indication that there may be an issue with the camera itself. As a final test in that case set the sound recording to manual and set the recording level to the middle level or further to the right. Check again to see if the sound levels begin to move. If they don't that is indicating that the issue is internal to the camera and it would be best to send it in for repair.
If the camera is picking up audio with the microphone unplugged, but not when it is plugged in that indicates the issue is with the microphone. If you have the Sound Recording set to manual make sure your record levels are set half way or further to the right before finalizing that determination. If the record level is too far to the left it can limit the audio enough that it doesn't pick anything up.
This was MOST helpful. Thank you.
So I did use a converter and the mic wasn't working. When I enabled sound on the built in mic, I could see the db meter moving. But the second I put in a mic or a converter to the mic, the db meter stopped moving.
I thought it was the mic or the converter. But I tried 3 different mics, and none of them need outside power.
I'm starting to wonder if it's an internal camera issue.