Dvd-rw Not Recogising Dvds

Well, I bought an (old) second-hand DVD read-writer, NEC ND-2510A.
When testing it recognized and seemed to work with CDs but not DVDs (a prerecorded one which worked my other DVD player [brand unknown]).
I suspect - or I'd like to check - that the laser used to read DVDs is working. (I understand, and please correct me if I am wrong, that in such components, there are either two discrete lasers of different wavelengths or one laser chip with a dual wavelength laser on in, in either case the shorter wavelength being for DVDs and the longer for CDs.) i.e., how do I defeat the interlocks and turn the laser on with e.g., the case open ? (I know about eye-safety)
How can I check if the laser or something easy to fix ?

Dumb_Question
6.June.2016

 

Is the optical media that the drive doesn't recognize DVD -R DL? The drive doesn't support that type of media.

 

Thank you for the interest, mdonah

I do not know the media type of the DVD I used to test the 'faulty' ND-2510A. The disk is prerecorded, and holds (is holding) 1.31 GB of data, according to my other DVD players, one of which is significantly an identical model ND-2510A

The only spec info I could find on the NEC website reads
"NEC's ND-2510A is a half-height optical drive with 8x write speed that supports DVD+/- formats and +R dual layer disc. It delivers high performance for writing and reading while being compatible with 10 optical disc varieties." https://support.necam.com/Legacy/Optical/ND2510a.cfm

The handy cdrinfo website gives a multitude of useful info though (the specs are at the start in clear tabular form) http://www.cdrinfo.com/Sections/Reviews/Specific.aspx?ArticleId=9803

Dumb_Question
9.June.2016

 

Have you tried a second DVD?
BTW The NEC ND-2510A was released in June 2004.

 

You could also make sure there are no scratches/debris on the DVD and if it's devoid of such, try using a laser lens cleaner,

 

->Eldon: This a good idea, but I have few DVDs to try...still I have a couple.
->mdonah: I have already tried cleaning the DVD, despite it appearing to be perfect. By laser lens cleaner, do you mean a cd that you can buy ? I did look at this but at the time I concluded they possibly did more harm than good, and I would better off, despite it being a lot more effort, opening the ODD, removing any dust which may have accumulated inside, and cleaning the lens in the manner approved by Coherent and Spectra Physics with a lens cleaning tissue and 100 percent IPA.

Dumb_Question
9.June.2016

 

You're correct about CD laser lens cleaners. I would do a manual clean.
Check your DVD - the NEC ND-2510A can only read/write DVD+R DL, not DVD-R DL.
Also, have a look at the image of the laser lens in your second link.
http://www.cdrinfo.com/Sections/Articles/Sources/NEC_ND-2510A/Images/head_large.jpg - it shouldn't be too difficult to clean.

 

I use a lens cleaner that you put a couple of drops of the cleaning solution on and run it. I haven't had any problems BUT, I haven't had to use it in quite a while. I have interchangeable drives for my Latitude E6400 and 4 external optical drives of varying capabilities including a BDXL mDisk.

 

Google for firmware updates, usually flashing a newer firmware will improve disk compatibility.