"Scott" wrote in message
...
Arfa Daily wrote:

You are brave to recommend these !

IMHO, if you want to do no good at all at best, and actually damage the
laser at worst, use a cleaning disc with little brushes on it ... On
several occasions, I have seen an otherwise good laser wrecked by the
brush getting caught in the lens suspension, and tearing this off with
the high rotational speed of a DVD.

Don't tell me that But since a laser cleaning CD kit is a 'CD' wouldn't
the DVD player use the rotational speed for a CD?

Well, once it has determined that it *is* a CD, it might, but there are a
couple of qualifiers here. Firstly, most DVD players assume a DVD first, so
spin up to full speed in readiness for that. They only then slow back down
to CD speed, once they've determined that the data streaming off the disc is
CD audio, not DVD video and audio. Secondly, some DVD players run CDs at
full speed also, much like a personal CD player runs the disc at high speed,
when in anti-shock mode ( to keep the bit bucket full ). Thirdly, some
players have a lot of trouble making any sense of a cleaning disc. I don't
know whether this is an issue with the data contained on them, or whether
it's an issue with the brushes whacking the lens on every rotation, and
vibrating it about its correct focus point. Whatever it is anyway, some
players just will not lock their spindle servos on these discs, and they
just run at very high speed, totally out of control. At the end of the day,
the only way to clean a laser lens, is 'properly' - that is by hand,
carefully, with nothing more aggressive than electronics grade IPA. Even
then, any improvement may be only marginal or temporary as, if dust on the
lens was the primary cause of whatever problem was apparent, the chances are
that there is also dust on the critical angle mirror and the face of the
pickup photodiode array, both of which are internal components of the
optical block ( laser ) that you can't get at to clean. And again, DVD
lasers seldom collect dust on their lens, due to the blanket of air dragged
round under the disc, by its high rotational speed.

Arfa