I am using an NEC 3500 DVD Burner in a firewire case connected to a Mac. I've been using it since November 2004 with no problems. I even flashed the firmware to version 2.1a without trouble. (I did have to remove it from the firewire case and temporarily install it internally on an ATA connection.)
Just a couple of days ago, I started having problems on playback. I thought the burned DVD-Rs were the problem but I tried them in my Pioneer 107D burner and my home DVD player and they were fine.
I then tried some commercially produced dvds with the same results. Somewhere in the first 30 seconds of playback, I start getting "pixelated" glitches showing up. The unit will burn dvds fine but I can't figure out what to do to improve the playback.
I've checked with some people and the suggestions were: the software - but it works fine with the Pioneer and had been working fine with the NEC; the firewire connection - don't know why that would have changed; not enough memory for the computer to process it quickly enough - I have a gig of RAM; and finally, the unit is going south.
I'm going to try to connect it internally and see if the playback issues continue. Otherwise, any other ideas?