I was wondering why a CD player that previously used to play CD-Rs now isn't able to read them?

It will still play normal pressed CDs.

The normal CDs have a silver coloured surface whereas the CD-Rs have a green coloured surface.

I was wondering why a CD player that previously used to play CD-Rs now
isn't able to read them?

It will still play normal pressed CDs.

The normal CDs have a silver coloured surface whereas the CD-Rs have a
green coloured surface.

If it's now failing to play specific CD-Rs that it used to play, then
this could indicate that the player's laser diode is getting near the
end of its life. Its output is dropping, resulting in a weaker signal
reflected from the disc's data layer, and the photodiode in the reader
assembly isn't getting a strong enough reflection to track the data
spiral and/or decode the data bitstream.

The same effect could result if you've got a buildup of dust or
tobacco-smoke tar on the laser diode or the photodiode. The more
light is blocked or scattered by these materials, the weaker the
detected signal.

CD-R discs already produce a weaker reflected data signal than an
"pressed" CD. CD-RW discs are (usually) even weaker. So, a CD player
which is "dying" will usually being to reject CD-RW discs first, then
CD-R, and then finally "pressed" CDs.

If it's a CD player of particularly high value, it may be possible to
have the optical assembly, or even the entire "loader" mechanism
replaced. For cheap CD players, alas, the cost of servicing them is
usually more than the cost of buying a new one (if the service parts
are even available).

If the problem affects newly-burned CD-R discs, more than older CD-R
discs you made years ago, then the newer CD-R blanks may be to blame.
Some brands and types of CD-R disc have poor reflectivity, and the
"80-minute" CD-R discs (which are pretty much the only kind you can
find these days) are inherently harder to track than the "72-minute"
variety which used to be the standard.

David Platt wrote:

The same effect could result if you've got a buildup of dust or
tobacco-smoke tar on the laser diode or the photodiode. The more
light is blocked or scattered by these materials, the weaker the
detected signal.

Arfa and I have had a running discussion about this over the years on this
group.

I live 3,000 feet up in the desert, the air is dry and dusty. There is
plenty of wind all the time so there is no hydrocarbon buildup from
automobile exhaust.

The cleaning disks with the brushes work fine for me, I have never had
one scratch a lens, and they brush the dust off.

Arfa lives in England and has very different weather and the dust is more
of a sluge than dry dust. He always cleans his lenses differently.

(Arfa, want to chime in here?)

Geoff.



--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

"Geoffrey S. Mendelson" wrote in message
...
David Platt wrote:

The same effect could result if you've got a buildup of dust or
tobacco-smoke tar on the laser diode or the photodiode. The more
light is blocked or scattered by these materials, the weaker the
detected signal.

Arfa and I have had a running discussion about this over the years on this
group.

I live 3,000 feet up in the desert, the air is dry and dusty. There is
plenty of wind all the time so there is no hydrocarbon buildup from
automobile exhaust.

The cleaning disks with the brushes work fine for me, I have never had
one scratch a lens, and they brush the dust off.

Arfa lives in England and has very different weather and the dust is more
of a sluge than dry dust. He always cleans his lenses differently.

(Arfa, want to chime in here?)

Geoff.



--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379



The laser must be focused sufficiently well to start with or the cleaning
disc will never spin.

The brush glued to the disc does a crappy job at best. Manual cleaning is
really the way to go.

I routinely measure the HF pattern from the laser before and after cleaning.
I have never seen a detectable increase in the peak-to-peak level of the HF
pattern after using a cleaning disc.

An increase of 25% to 50% after a proper manual cleaning is not unusual.

Mark Z.

Thanks for all the replies so far, I have a few more questions:

Why does the laser degrade? Does using CD-Rs degrade the laser faster?

We don't live in a very dusty area!

I have only tried a disc cleaner which has small brushes stuck to it. How would I manually clean the laser - using IPA and a cotton swab?

Is it possible to increase the laser output or adjust it easily?

Thanks.

M.Joshi wrote:

Why does the laser degrade? Does using CD-Rs degrade the laser faster?

It's a tiny LED that burns up as you use it. Eventually it "goes dark",
but inbetween that and full brightness is a lot of time.


I have only tried a disc cleaner which has small brushes stuck to it.
How would I manually clean the laser - using IPA and a cotton swab?


That's the usual plan. It has never worked for me because the IPA will
make a sludge out of the dust. It probably will work for you.


Is it possible to increase the laser output or adjust it easily?

Most CD players, DVD players, and computer drives have a "brightness"
control to adjust the output of the laser.

The problem with that is unless you can measure the output, you are guessing,
and if you guess too high, the laser will be dead in seconds. If you guess
right, or measure it, the diode will produce more output, but it will also
burn up faster.

So you may be able to get more time out of it, but in the end, this is a
signal to either replace the diode, or the player.

On the other hand, you may be experiencing reduced output due to capacitor
failure, so the first thing to do after cleaning it, is to poke around with
a voltmeter and a voltage chart if you have one and the necessary skills.

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379