This dead side of a large-box copy of "The Seven Percent Solution" has an odd angular pattern near the end - like it was a test disk of some sort:



Content wise, it's not interesting sadly - looks like side 2 of Ruggles of Red Gap. My production (later side-open sticker) copy doesn't have this odd pattern though.

That pattern does indeed indicate that the dead side was produced very early in Discovision's life. I have quite a few of these of these but they do not affect play. Can you read the numbers on the outer ring?

I don't see any numbers, alas.

Any idea why they mastered them this way? Was it to try to make them play easier on Magnavisions (which needed all the help they could get - and then some, aparently...)

I was originally thinking it was an experiment along the way to a CAV/CLV hybrid, where the disk could go from 2 to 4 fields or somesuch.

I have no idea why some discs have this twist pattern and others do not. I have never found reason for the pattern, except it is on earlier pressings. I've got titles where all sides have this twist.

Thinking about it some more, maybe the earliest mastering equipment wasn't quite 100% accurate nearer the end of a disk? It's such a minor thing that they probably let it slide.

You could be right happycube. It was an early mastering error. I was told that the problem was corrected rather quickly so when you find a disc or an entire set with this misalignment of the disc information, you have a very early disc.

There should be a number in the outer ring. Either a three digit number starting with 9 (as in 958) or a four digit number starting with 10 (as in 1018). These numbers are the test numbers or early catalog numbers are are only found on very early discs before they started using the catalog numbers, (in this case 21-018). I have a long list of early numbers but I have yet to find a Ruggles. The number can be very hard to see on some Discovision discs but I have found that it is easier in sunlight with the disc slightly tilted.

It looks something like M21-1018-3, but the sun's down enough to make it very hard to read. I'll try a lighted mag. glass at work tomorrow.

Was hoping this was something more interesting, but ah well

I suspect it is W21-018B-3

Here is an interesting one...



This is side 1 of "Coral Divers of Corsica" http://www.lddb.com/laserdisc/28692/51-013

This copy is encoded as CAV and plays like a CAV disc, except none of the CAV features work. This is similar to Side 3 of Deliverance http://www.lddb.com/laserdisc/28568/W10-519 that is encoded as CAV but is actually CLV. The difference between Deliverance and this title, is the RPMs remain constant for this disc.

Interesting - I wouldn't be surprised if it was the same problem, just a much worse case of it - the mastering was probably a few RPM off (if that), unlike the other disks where it was a very small (but visible) fraction off.

If it was misencoded CLV the recorded bit would probably not go as close to the end of the disk, either.