"Jumpster Jiver" wrote in message
news:7XK%e.14881$J03.13211@trndny05...
Maxmel wrote:

Hi , I'm just wondering if it's possible to adjust or at least verify the
laser of a DVD or CD player without a laser beam checker.

I have a 500MHz scope and a god expertise in electronics but never play
with DVD/Cd laser Assy.

Problem is the DVD player doesn't play always the DVD inside , lens has
been cleaned.

I'm assuming that these steps are standard for all tha models.

Also , what is the difference between the laser of a DVD and a CD ?

Why a DVD laser can read CD and not the inverse.

Thanks a lot for your help.
To verify that the laser is operating remove any clamps or items that
would block your direct view of the lens and glance at it when it should
be reading a disc.
The laser is focused to read a disc that is close to the lens, so it will
not be focused on your eye's retina. While I would not advise staring at
a CD/DVD laser for any length of time, a passing glance will not cause eye
damage or injury even if you do it a thousand times!

However this will not verify the correct output power or the sensor's
ability to read the reflected signal from the disc.

Whilst it is probably true that the laser will not cause any eye damage, all
manufacturers recommend that if you must look at it, do it obliquely from an
angle of 45 degrees or so. Also remember that a CD laser is basically in the
infra red spectrum, and emits very little visible light, so can be difficult
to see, encouraging people to try to look closer and directly in the top, to
check if its burning.

The DVD laser can, of course, be seen actually through the disc, so in a lot
of cases where the centre of the disc is not obscured by a large clamp
holder, you can see if the laser is burning with the disc in place.

Personally, I would never look directly into a laser, no matter what the
physics dictates, or how low the power is.

Arfa