Blurry Video On A DVDR Recording

I swapped out an Ilo DVDR05ZU for an Ilo DVDR05MU. I was told by a
CyberHome tech support person that the ZU and MU versions have
different chip sets. The "servo" (laser mechanism) appears to be the
same because the same "front end" firmware is used on both types.

I had previously formatted some Verbatim DVDR +RW discs with the ZU
unit and used one to test the new MU unit. I recorded 5 minute
segments from each of the major broadcast TV stations. I used 4 hour
resolution which worked fine on the ZU unit with a 19" TV set. The
recordings from the MU unit were slightly blurry.

I ran a Nero CD-DVD Speed Scan on the disc and it did not look all
that good. So I did a full erase, wrote the test data on it and reran
the Scan. This time the scan looked perfect - not one defect. I
concludes that it was not the disc but the new MU unit that had
produced a corrupted recording.

I did a full erase on that disc and used the Format feature on the
DVDR. Then I ran the same tests and this time the video quality was as
good as with the ZU unit. I have done several recordings at various
resolutions and they appear similar to the same kind of test with the
old ZU unit.

I tentatively conclude that it is necessary to perform the Format
using the unit that will be used to make the recordings. I suppose the
Format procedure puts down some kind of code that is used by the DVDR
later when it comes time to do the actual recording and that causes
the unit to perform properly.

Comments please.

--

If you build a man a fire and he will be warm for a day. If you
set a man on fire, he will be warm for the rest of his life.

Bob