Px716a: burning problems

Since today my PX 716a doesnt burn my dvd media right.
I bought my burner in January 2005 I always use the same DVD+R media (Verbatim DataLifePlus 16x, MCC 004) and I didnt change anything on my PC System for months. Its TLA 0203.

After approximately 1 minute burning i can hear that the dvd media spins down as like the burner reduces burn speed although the buffer of the recorder and reading buffer is still full.
The burn seems to end properly in both Nero 6 Ultra Edition and PlexTools Professional but lasts 1:30 minutes longer than usual. Normally it lasts about 6 minutes for a full DVD, now is lasts about 7:30 minutes.

But the problem comes now:
When I try to read the burned media, my PC, my Notebook and my Stand alone DVD Player doesnt recognize it. The burner blinks 5 times in a row with a short break after it and repeats this endlessly.
I tried different types of data (movies, mp3) and different kinds of burning speed but its always the same.
I just produced 8 Coasters (which is 8 times more than before this problem) and I think my PX 716a seems to be defective. Maybe the laser adjustment is wrong but its only a thought from my non professional sight.

Does someone has an idea whats wrong with my Plex?

ps.: sorry for my messy english… =)

Try the self test (in manual or search here). If it fails, RMA the drive if still under warranty.

the blink codes mean something is wrong. go to the plextor website a look under tech support for the chart on blink codes, i will look for it also.

also, what color is blinking? amber or green?

here is the link for blink codes http://www.plextor.com/english/support/plexhelper/atapi/blink716A-SAandUF.htm

I just received a new px-716 from Plextor without sending in my defective unit.
The whole RMA Process took about 4 working days. Respect to Plextor.
Its a brand new TLA 0309 assembled in November.

I should do a few tests with plextools in the next days… =)