All mini-DV decks are not created equal...
 

I have a PV852 Panasonic camera that I used for shooting videos. It is a great camera, but my firewire isn't working from it. I went out and bought a JVC 650GR camera from CC for around $200.00 to use as a Deck. Well, even though I have been told over and over that mini-dv's as deck work well, this hasn't. When I play back the tape from the PC852 to the JVC, the sound cuts in and out and also has some static.
This only happens from Pana > JVC. All the tapes that originated on the JVC play fine and sound great.
So what am I to do? Anyone else experience this problem?
My only thought is that I was running an external mic into the PV852, but I fail to see how this could affect anything.
Anyone have something similar happen?

Sometimes different DV devices will have different head alignments... so the deck that will playback a tape best is the camera used to shoot that tape.

You could try record a tape on the JVC camera to check.

Glenn's diagnose is correct - your issue is tape path alignment.

Now, you need to determine which camcorder is out of alignment. Take a tape shot with your old camera and play it back on 2-3 other camcorders (thinks friends, relatives, most everyone has one nowadays). If that tape plays fine in all other camcorders, then take your new camcorder back immediately for an exchange - it's not aligned properly; it will play it's own recordings because record and playback paths are the same, but it won't play any other tape right, and the tapes you record with it, will not play properly on any other players.