Is PCDP dying?
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chillysalsa

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K, I've got a Sony D-E445 from a few years back, and it skips like CrAzY. Here's the catch, it plays CDRs just fine, it's just originals that make it choke! I've noticed it's particularly bad on some discs, and even particular tracks on the disc.

Any CDR plays OK though?!?. I've tried cleaning the lens with q-tip and alcohol. I noticed tiny pieces of dust around the lens, and I carefully removed them with tweezers. Still, no improvement...


Is the laser just dying?

Are originals of lesser quality than CDRs, thus explaining why CDRs still play ok???

thanks for any suggestions...
 
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linnem

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It's usually the other way around...
The police have made an album about your problem, it is called "Ghost in the machine".
 
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ai0tron

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I'm sure you saw the label by the laser that said "DO NOT TOUCH" Right??? Well aside from probably screwing it further with that Q-tip, the reasons why it plays CDR's and not CD's is that CDR's are closer to centered than any CD. The reason for this is that your typical cd is actually a pressing which means that no matter how hard they try there will always be microscopic deviation from center. Where as a CDR is created on a CD spindle as it spins so the burn tracks are naturally centered perfectly. Also because the average computer CDROM is much faster than the average cdplayer it is able to perform alot more error checking and so the copy of the CD will benefit in that respect as well.
 
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myself, aka me

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Uh... isopropyl (91%) applied carefully with a cotton bud on a stick, can fix dirty lenses. Unless the repair FAQ is lying, which it isn't, as it fixed my MDs lens..
 
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ai0tron

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There are special devices, not Q-tips, available to clean CDP lenses.

I think the repair FAQ wants you to break your MD so youll have to buy a new one.
 
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Zurg

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All CDs and CDRs have bit errors at the raw data level. Fortunately, there is a fairly robust error detection and correction algorithm that takes advantage of redundant data encoded into the raw data stream. This typically allows the CD player to perfectly reconstruct the original data stream despite the bit errors in the raw data. As a CD ages. the bit error rate typically increases. Eventually, a CD may get to the point where the data cannot be reconstructed accurately and the player has to try to make the dropout as unnoticable as possible.

Studies I have read indicate that original pressed CDs typically have very much higher bit error rates than typical CDRs. This means that a copied CD will likely have fewer errors, in the raw data stream, than the original. This should make absolutely no difference in playback if both the CD and CDR can be read well enough to perfectly reconstruct the audio data. The lower bit error rate of the CDR, however, may allow it to play back on some equipment, without dropouts, when the original may fail, due to its' higher bit error rate.

This, of course, presumes that your CD burner is able to read the original either perfectly or at least better than your CD player. Since CD burners, with appropriate software like EAC, don't have to read the data in a single real time pass, they can provide more robust extraction of CD information.

Z
 
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Gluegun

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So has anyone made a component CD player that *doesn't* read a CD in one realtime pass? But copies it bit for bit to a hard drive or some RAM with something like EAC, and then decodes it that way??
 
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Whitebread

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Wouldn't there be some delay when first starting play with the player?
 
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Mystic

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"So has anyone made a component CD player that *doesn't* read a CD in one realtime pass? But copies it bit for bit to a hard drive or some RAM with something like EAC, and then decodes it that way??"

I don't know about CDPs but my MD (N707) works that way. It only spins the disk every 30 sec or so. It reads in a bunch of data and stores it in a buffer. As the buffer gets low, it reads in some more. I'm assuming this is to save on battery life and would not impact sound quality. Real time error correction is no problem for CDPs.
 
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pedxing

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Quote:

Originally posted by Whitebread
Wouldn't there be some delay when first starting play with the player?


Depends on the design. Apparently, most systems seem to be able to read CD's many times faster than usual, meaning they can read data off the CD faster than what is actually being played back. They read in bursts and if they usually encounter an error, they might try to read that section of the CD again. I htink this is how anti-shock stuff on portable CD and car CD players work.

Therefore, the pause in the beginning might not exist or is signifcantly reduced because of the faster speeds a CD player can read the disc. Of course, faster you spin the disc, the harder it is to read warped or defective disc because the tracking mechanism won't have as much time to compensate for funny physical defects. MY lousy sony pcdp can read most of my scratched medium without G-protection turned on. When I turn on G-protection, it skips more often with scratched CD's and the spindle motor spins faster. If I burn a copy of my scratched source (as Zurg said above) and play it on my sony pcdp with g-shock, the skipping occurs infrequenctly assuming that the scratched sections of the disk were readable or fixable (through error correction) by my computer.

Lets not enter the realm of discussing which CDR media sounds better....
 
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Whitebread

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I c
 
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myself, aka me

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Quote:

Originally posted by ai0tron
There are special devices, not Q-tips, available to clean CDP lenses.

I think the repair FAQ wants you to break your MD so youll have to buy a new one.


It isn't dead yet.. Mind you, it is an R37, kinda tough. My E900, was skipping like mad, now works okay 60% of the time.. I think its more the oil etc. on your skin rather than scratching it. Anyway, a cotton bud on a stick worked..

I might just add, the liquid that high end hi-fi stores sells is just isopropyl. Most likely 91% stuff or higher.

What cleaners DON'T touch the lens? I know those horrible CDs with a brush glued on the bottom are bad for the unit and useless...
 
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