Well it turns out I was mistaken. My Panansonic is also an RV30, not a DV30 as I first reported. And it does work fine with any - format either -R or -R/W but hates +R/W! I have not tried +R though. I often make a trial on +R/W media when I am not sure how something is going to work. So if I want to try it in the Panasonic I have to first copy it to a - format disc. But I also have several A04's and an A05 at home so that is not a problem. I like to use the Panasonic for a test case figuring if it works on it then it should work on any player.
I don't give away or sell DVD's but occasionally someone in my family will want to borrow one. It is embarrassing for them to later tell me "It didn't work"!
Bet you know what I mean!
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