A problem with a cd player

On 1/27/2009 11:23 PM Gaetan Mailloux spake thus:

You don't need a schematic to figure out that many CD players have problems with CD-R discs. I've seen this on my own equipment. Depends on the type of CD-R discs *and* the recorder they were burned on.

Home recorded CDs ain't the same as commercial ones and some CD players simply can't cope with them. And re-recordable seem to be more prone to these problems than use once types. Think it's to do with the type of reflective layer. Strangely, very old ones seem ok - I have an early Philips dating from the '80s which does. Newish ones should be ok too. It's the inbetweens that can be a problem.

Likely to be poor laser performance. CD-R discs are nowhere near as reflective as commercial 'pressed' types, and many players that were not specifically designed to cope with them, struggle, particularly if the laser is marginal, or even dirty. Have you, as a first move, tried cleaning the lens ? (properly with alcohol etc, not a cleaner disc).

As you get further into a disc, its rotational speed falls to maintain CAV. If the performance of the spindle motor is anything less than perfect, its speed can be minutely erratic. If the performance of the laser is down as well, then when you combine these factors, which are typically present in any player older than a few years, the result tends to be poor tracking performance / general playability problems on late tracks, and this will be exacerbated by use of CD-R discs.

Arfa

Try burning the CDs at a slower speed.

I agree - the OP should definitely clean the laser. Other maintenance, such as cleaning and lubricating other moving parts - rails, gears, motor spindles, etc, is also indicated. If after cleaning and maintenance issues are resolved the problem persists, another brand of CD-R's might help, or the laser may just be deteriorated to that point, especially if in a dusty and/or smoky environment.

Perhaps because audio CD's are CLV...

;-)

Mark Z.

CAV.

I hate to jump on you, Arfa, because you are incredibly knowledgable, but CDs are CLV, not CAV.

Also, technically speaking, it should be "further out of a disc" (as disks are read from the inside out).

Nit picking. :)

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Agreed 100%.

Hello

Cleaning the laser lens and lubricating the mechanicals was the first thing I have done.

I did try other cd-r brand but the problems still there.

Maby the laser are at the end of his life ?

Thank

Bye

Gaetan

but

disks

is

in the

Linguistically shouldn't it be "farther out of a disc", further for time, farther for distance.

Any more nits?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Yeah, OK Mark. CLV servo it is ! Just another senior moment. I seem to have more of them these days ... :-(

Still, the rest of what I said is valid.

Arfa

Yes indeed. See my reply to Mark. As far as "further into a disc" goes, we're just looking at it from two different angles. You are looking at it from the physical side, as indeed, the laser does read from the inside out. I was looking at it from the time angle - as in further into the disc's musical content.

Arfa

I was talking time, hence my using the word "further". See my reply to William.

Arfa

I knew that you knew that. I was just foolin' around.

mz

If you have access to an oscilloscope, the HF "eye" pattern can be observed, and may be noisy. This would account for the deteriorated performance first on CD-R's. As previously noted, this is often the result of dust and smoke contamination. The finest particles get inside the laser, and settle on the turning mirror as a fine film. This diffuses the reflected laser light coming back off the disc before it can really be read. It is sometimes worthwhile to adjust the Focus Offset for maximum amplitude as viewed on the scope. If it makes a difference of about 20% or more, this may solve your problem, at least for the short term.

Mark Z.

Mark Z.

Yeah, I know that Mark. Dunno. The older I get, the more this nonsense seems to just fly out of my mouth (fingers) ... Perhaps I'm going down with some kind of early addle-brain. There's a prog on the telly next week about poor old Terry Pratchett. He first noticed something was wrong, when he kept typing spelleen misstaykes :-( I think that my problem is that I spend too much late-night time sitting in front of this idiot machine, instead of getting some sleep ...

Arfa

Same problem here. Gets frustrating at times. I'll stop mid-sentence because I can't bring forth a noun to continue. Then after perhaps 2 or 3 seconds it comes and I finish the sentence. Short-term memory getting worse also, although in truth this has always been a weakness of mine. Still able to function at work though, so that's a blessing.

My hearing is getting really bad also.

With me it's early morning. I get up around 3:30 to 4:00 AM most days.

Spend a lot of time perusing old analog meters etc on eBay. Added several to my collection lately, including an AVO 8 which I got interested in after finding you had one. It's a Mark 5 Nato model, on it's way from Germany as we speak. Not many AVO's in the U.S. it turns out...

Added several Simpsons (the American answer to AVO?) lately as well. The guy at simpson260.com has offered to sell me his 9 remaining Simpsons. I don't think I can do that though, nowhere to put them!

Mark Z.

machine,

There's nothing wrong with you. As you get older, you're more likely to drop words or letters from your posts. And as time seems to pass faster, you have less time and inclination to think carefully about what you've written.

Those large AVOs were to be found pretty well everywhere even vaguely connected with electronics in the UK. Still available new up until recently - at about $1000. My original one got stolen many years ago - and like many others I just used a DVM instead. But always wanted another - and got a perfect condition one off Ebay a few years ago. Nothing else quite matches the tactile switches. ;-) And of course if working to old service sheets, voltage measurements were near always made on one so allowed for the loading.