Perhaps recent firmware updates have caused a compatability problem with older DVDs.
Or, if your machine can't update its firmware, try a more modern machine that can?
in fact, I have tested the damaged discs at a DVD player more modern than the one I recently have. Not to mention that it is region-free too. Unfortunately, the result is the same. The discs stops at exactly the same place. The same when I play them on my computer and I bought the computer this year.
Lance wrote:
This is actually (unfortunately) quite a common thing. It's called "Disc Rot".
Obligatory Wikipedia link:
http://en.wikipedia.org/wiki/Disc_rot
Everything on Earth is subject to basic entropy, and unfortunately optical media (digital media, for that matter) is no exception to that. Blu-Ray discs are apparently authored in a way which extends their life considerably longer than DVD and CD based media. But yeah, nothing is infaliable, and discs are gonna decay over time, no matter what we do.....
And the extent to which they do is somewhat random. It can't be predicted why, or when, it will happen. My TOS DVDs actually suffered from it on the Season 3 set. They all used to work, then one day one of the discs just... didn't anymore.
The first Star Trek DVD:s I bought were the season 1-3 Voyager DVD:s which I bought in "February 2006. They are still working perfect (just in case, I will do a main "Voyager rewatch in the coming months to see if they are still OK). I also have some rock videos older than the Voyager DVD:s which still works.
As for the DS9 season 1 DVD.s, I watched them once before they started to malfunction about a week ago. They should last longer than that.
As for discs in common, I bought my first CD records in 1990 and they are still playable, just as if they are new.