We recently shot a high school graduation with our HVX200s. On one camera, we took internal mic on channel 1. The nat sound from that camera sounded overmodulated (crackling, etc.). I didn't have a chance to see the levels on the camera meters before the P2 card was wiped. Since that shoot, that camera's channel 1 internal mic records about 6 to 8db lower than it's channel 2 at the same pot settings. The recorded audio isn't distorted, just unusably low. The XLR inputs work fine in mic and line. But any audio recorded internally to channels 1 (or 3 in DV50 mode) is low. So, silly scary question time.
Does it sound like something's blown in the mic circuitry and is it tech time for our beloved Panny?
Doesn't sound like there's anything majorly wrong with the audio so much as you can't expect a whole lot from on-board mics. They are really just there to prove the audio circuitry works and not for usable audio. But if they don't read fairly close at the same exact settings, sure it's worth having a look at.