"William Sommerwerck" wrote in message
...
If the unit is well-designed, there should be no need to do anything
more than solder it in place.

However, it's likely you'll have to perform a drive-current adjustment.
This might require a special test disk and/or test equipment. The
service manual should fill you in.

Thanks, I've never really thought about it this way. The unit would
have to be designed in a way to make it quick to assemble and I think
it would slow things down far too much on the production line if they
had to align the laser on each unit. Also, the laser diode for this
drive is a Sony patent and is designed for this laser assembly only so
I'm guessing a drive-current adjustment won't be required either.


Actually, I would go with what Arfa says. What I said was "common
sense" --
but probably isn't correct.

With respect to production lines... It isn't how "difficult" it is to do
something -- especially if the difficulty is reduced by the use of custom
fixtures and test equipment -- but by how long it takes. One of the
reasons
"modern" electronic equipment is so much cheaper is a high level of
integration (ie, fewer parts) combined with much less human labor. And if
you can get that labor Really Cheap overseas, so much the better.

I do, however, find it hard to believe that laser-diode installation
requres
extremely precise adjustments. This (to me) indicates poor product design.
Of course, I'm not omniscient in such matters.



The laser diode itself (in my experience) has a flat, unfocused lens. The
focusing, grating, etc comes in later. I have successfully replaced laser
diodes but as Arfa says, the problem is often not the diode itself, but
other problems in the optic path.
One symptom of a failing laser diode (on conventional DVD players) seems to
be a situation where the unit plays OK for perhaps 15 minutes to 1/2 hour,
then starts skipping, pausing, pixelizing, etc. As the laser diode warms up,
emission declines, and soon the bit errors exceed the error correction
capability of the electronics. Less critical on an audio CD, but seems to
reach a fatal level pretty quickly in DVD players, and I assume BD players
may be even more critical - though I've yet to have much experience on
those.

Mark Z.