I have an old DVD player as well that only supports TY's. I tested out the Memorex TY's a few months back and they DIDN'T work. I used CDidentifier and the disc were different, although both still TY's. Not that it really matters, the Memorex disc were able to store a few more secs of data.
Anyway, I've used TDK TY's (which are hard to find in my area) and Fuji's and they seem to work 70% of the time, and only if burned at 4-8x. I pretty much stop using CD-Rs altogether and use Hi-Speed CD-RW's to watch stuff on my player. Personally, I'm just waiting for a DVD player to come out w/ all the features I'm looking for so I can stop this TY/CD-RW silliness.