I just wanted to post in case this info helps anyone. I used a combination of suggestions from this forum. My JVC DR-MH30 would not finish starting up but it didn't flash loading like everyone else complains of. It just replayed the JVC DVD Video Recorder animated graphic endlessly. JVC was no help at all.

Someone said that their disc door was stuck and I did notice that mine wouldn't open and it made a weird whirring noise for a few seconds when turning it on, before the graphics looping would start. Holding the eject button while powering on did not help (nor did unplugging, even for 2 weeks), but inside of the DVD door on the bottom right of the drive was a little silver button. Pressing that button opened the door. Then I closed it and turned off the unit. Pressing the eject button by itself (no power button) turned it back on. The door opened again and no more looping. It works as usual now. (Unfortunately, it took me over a month to figure out the problem, but I'm still happy.)

Just in case it's important, there is also a little pinhole to the left of the silver button. I tried that first not noticing the button (which was partially hidden by the front of the case). At one point when using a paperclip, it made a spinning noise, but it didn't open. Then I eventually bumped the silver button by accident and the door popped open... So if the button by itself doesn't work at first, I would try the paperclip in the pinhole and then the button.