Jumpster Jiver writes:

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.

Keep in mind that if it is trying to read a CD, the wavelength is
780 nm and barely visible. For DVDs, it is like a lase pointer, but
they are both highly divergent.

DON'T look straight down because if for some reason the lens fell out,
the beam may be collimated, which WOULD focus on your retina.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

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