CD/MP3 player laser diode problem

[Vadik Mura]

Hi there i have a small problem.
I have a CD/MP3/VCD player, everything was ok till one day when the
Anti-shock disappeared.
I went to my friend who sad that it just needs to be attuned, there is
a diode(in form of a screw,at the back of the lens,that can be
rotated).He attuned it for several hours and now the lens can't focus,
on that diode are some signs(like 2,6, and an arrow, access my web
page where i wrote a better description)
http://moldova.cc/affa/cdx.htm

Thx. for help

 

[LASERandDVDfan]

Hi there i have a small problem.
I have a CD/MP3/VCD player, everything was ok till one day when the
Anti-shock disappeared.
I went to my friend who sad that it just needs to be attuned, there is
a diode(in form of a screw,at the back of the lens,that can be
rotated).He attuned it for several hours and now the lens can't focus,
on that diode are some signs(like 2,6, and an arrow, access my web
page where i wrote a better description)
http://moldova.cc/affa/cdx.htm

First off, that "laser diode screw" is called the laser gain potentiometer.

Second, I hope he didn't try to adjust it while the laser was actually working.
If the pot was noisy, then it's very likely that he damaged the laser even
further.

Third, to make successful adjustments to the laser, tracking, and focus
settings, you really need the right kind of tools and good knowledge and
experience. But these settings are usually optimal in the first place, so your
friend should have looked elsewhere for the problem rather than blindly
tweaking to the point where you'd need an oscilliscope and the correct service
materials to put the adjustments back to where they are supposed to be set.

Forth, did he ever bother to test the player thoroughly to ascertain accurately
what was wrong with it?

Fifth, what's the brand and model number? From the pics, it painfully looks
like a Philips. - Reinhart

 

[Patch]

"Vadik Mura" <axney@yahoo.com> wrote in message
news:95c0a6de.0310220551.5960a249@posting.google.com...

Hi there i have a small problem.
I have a CD/MP3/VCD player, everything was ok till one day when the
Anti-shock disappeared.
I went to my friend who sad that it just needs to be attuned, there is
a diode(in form of a screw,at the back of the lens,that can be
rotated).He attuned it for several hours and now the lens can't focus,
on that diode are some signs(like 2,6, and an arrow, access my web
page where i wrote a better description)
http://moldova.cc/affa/cdx.htm

Thx. for help

You can't just start tweaking adjustments & expect it to work. You will need
to do an alignment with the proper test equipment.

 

[William P.N. Smith]

axney@yahoo.com (Vadik Mura) wrote:

Hi there i have a small problem.

No, you _had_ a small problem, now you _have_ a big problem! 8*)

I have a CD/MP3/VCD player, everything was ok till one day when the
Anti-shock disappeared.

Was it still playing OK after the Anti-shock disappeared?

I went to my friend who sad that it just needs to be attuned, there is
a diode(in form of a screw,at the back of the lens,that can be
rotated).He attuned it for several hours and now the lens can't focus,

Playing with the physical calibration of a system like that is just
asking for trouble. While a factory authorized service place _might_
be able to re-tune it (for a fairly large chunk of change), it's also
likely that your friend broke something while mucking about.

I'd have tried cleaning the lens first, and then thrown it away if
that didn't help. Too many things nowadays are more expensive to
repair than replace...

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com

 

On 22 Oct 2003 06:51:24 -0700, axney@yahoo.com (Vadik Mura) wrote:

Hi there i have a small problem.
I have a CD/MP3/VCD player, everything was ok till one day when the
Anti-shock disappeared.
I went to my friend who sad that it just needs to be attuned, there is
a diode(in form of a screw,at the back of the lens,that can be
rotated).He attuned it for several hours and now the lens can't focus,
on that diode are some signs(like 2,6, and an arrow, access my web
page where i wrote a better description)
http://moldova.cc/affa/cdx.htm

Thx. for help

Please define 'anti-shock disappeared. Are you saying it became
sensitive to vibration or shock? That 'diode screw' was probably the
laser power adjustment or worse one of the alignment settings.

If it's not working at all now, it's either way out of alignment or
the laser power is too far off, or the laser diode is damaged by too
much power. None of this is fixable without proper tools like an
o-scope.

-Chris

 

I'd have tried cleaning the lens first, and then thrown it away if
that didn't help. Too many things nowadays are more expensive to
repair than replace...

I'd have started with the obvious things like cleaning the lens and
track. If all else failed, I'd mark the adjustments before tweaking
the laser power up a hair. Failing that, I'd start turning everything
just before I took a sledge hammer to the remains. :}

-Chris