Help! My CD player sk-sk-sk-sk-skips
Jeff Dairiki
So I've had this Sony Portable CD player for three years or so. When
it was about a year old it started to skip occasionally. Now it skips
all the time, and its really getting too annoying to ignore.
(It really wasn't very mistreated either -- it's been lashed down tight
in a clean dry corner of my sailboat the whole time...)
So all the salepeople (can you really call them people?) at the stereo
stores around here say: "Oh yeah, of COURSE it skips. If its three years
old it supposed to skip. They all skip after a year or so. What you
need is an Alignment and Cleaning."
So I say: "How much?"
And they generally say: "Enh.. Somewhere's between sixty and a hundred
samolians..."
And I say: "But I can buy a whole new CD player for $120."
Then I get --The Shrug--.
So.... the big questions are:
Big Question #1:
What's does a "cleaning and alignment" entail? Is it just a little
spit polish with a clean ($100) sock? Something more?
Should I (an ex-fairly-competent-electrical-engineer) be able to do
this myself? Cleaning I'm sure I could handle (at least with the
proper advice). But, do I need special laser-guided tools to do the
alignment?
Big Question #2:
Is it really true that _all_ CD players (or at least all portable CD
players) will only last a year without maintainance? Suppose I
finally br-br-br-br-br-br-br-br-br-br-br-br-breakdown and decide to
buy a new one. Any recommendations? I don't need/want remote control,
programability, etc. and such, but I do value durability, and sound
quality (maybe I mean fidelity -- I guess sound quality depends on the
CD rather than the player.) -- On the other hand, I don't need top end
fidelity either -- It's in a freakin' sailboat afterall. (This is what
I keep telling myself.)
Ancillary Questions:
What, pray tell, is a '1-bit A/D converter'? (Sounds kinda like a
'yes gate'.) What does '8x oversampling mean'? What is the difference
between different CD players, other than how many buttons, shuffle play,
remote control and all that...? (Sony seems to make at least 12 different
portable CD players that all seem pretty much the same...)
Thanks for your time. Sorry to be so long-winded for such a stupid problem.
I will, of course, summarize if mail response warrants it.
Jeff "Ah, these old tapes aren't so bad afterall" Dairiki (KI6MO/7)
dai...@u.washington.edu
Wang
: If this is a FAQ, I have been naughty. I'm very sorry.
:
: So I've had this Sony Portable CD player for three years or so. When
: it was about a year old it started to skip occasionally. Now it skips
: all the time, and its really getting too annoying to ignore.
: (It really wasn't very mistreated either -- it's been lashed down tight
: in a clean dry corner of my sailboat the whole time...)
:
: So all the salepeople (can you really call them people?) at the stereo
: stores around here say: "Oh yeah, of COURSE it skips. If its three years
: old it supposed to skip. They all skip after a year or so. What you
: need is an Alignment and Cleaning."
of four - and skips ...
First I thought the CD is bad but meanwhile it skips on new CDs too!!
I thought that's the weak errorcorrection that the early little dingies
had. I still have no answer ..
I'll follow this thread.
/m
--
Michael Zacherl, Wang Austria Ltd., Vienna |
E-MAIL: m...@pag.wang.co.at | "Proof your chances,
PHONE: +43 (1) 89-111 ext. 433 | and leave them or not."
FAX: +43 (1) 894-17-14 |
timothy arheit
electronic repair.
Don't worry most of the time that skip dosen't usually take anything at all to.
fix. I've fix atleast a half dozen within the last year and it always been the
same problem. The thing is 1 or more years old and it has just started
skipping more and more.
Solution:
Take it apart leaving all wires connected. Somewhere inside there are
several pots for adjustment. (a small screwdriver will do) Somtimes they
are marked well as to what they do, sometimes you are not so lucky.
One of them adjusts the tracking sensitivity, this is the one you want.
Now the tricky part, With the thing apart (make sure you cause no shorts)
put a CD in and press play and adjust the pot. Turning it one direction
should make it skip continuously and the other way should tune it up till
it dosen't skip at all. Turning it all the way that way could make it skip
again though. (I've seen one's that are in 'tune' in the middle and one's in
'tune' near the edge.)
If you don't know which pot to adjust just mark where they start out (so you
can turn it back if it was the wrong one) and try them all.
It's also a good idea to clean the lense gently with a small piece of lense
paper while you have it apart, it can't hurt and it's usually easier to get
at while it's apart.
Of couse then put it back together.
I did this to mine a year ago when it started skipping and it hasn't skipped
since.
Good-Luck
Tim Arheit
-tar...@jupiter.cse.utoledo.edu
John Mallick
willing to shell out a lot of money to fix a first generation player, I opened up the case
and tried the following:
1. Cleaned the laser lens. Used some Kodak camera lens cleaner and tissues, followed by
an air-brush. Result: still skipped.
2. Cleaned and re-lubricated the rails on which the laser carriage rides. Tried both
Lubriplate (white grease) and Remington Rem-Oil (Teflon and oil for guns).
Result: still skipped.
3. Getting ready to toss the player. I went looking for some adjustment to fiddle with.
Found one on the laser diode board, but it was sealed and messing with it seemed like a
bad idea. Then I spotted a mechanical screw (partially hidden) which adjusted the angle
at which the laser rode on the carriage rails. Turned it 1/4 turn one way and tried a
disc. Result: skipping got worse. Turned it 1/2 turn the other way. Result: skipping
stopped!! Left well enough alone.
The player still works fine without skipping. So, if you can open up the CD player, you
might just find the same thing. There really aren't too many things to adjust or try.
Personally, I don't subscribe to the "yearly service" idea (if it ain't broke, don't fix
it).
--
John A. Mallick WA1HNL
GE Corporate Research and Development
Schenectady, NY 12301
George Durden
> dai...@milton.u.washington.edu (Jeff Dairiki) writes:
> : If this is a FAQ, I have been naughty. I'm very sorry.
> :
> : So I've had this Sony Portable CD player for three years or so. When
> : it was about a year old it started to skip occasionally. Now it skips
> : all the time, and its really getting too annoying to ignore.
> : (It really wasn't very mistreated either -- it's been lashed down tight
> : in a clean dry corner of my sailboat the whole time...)
> :
> : So all the salepeople (can you really call them people?) at the stereo
> : stores around here say: "Oh yeah, of COURSE it skips. If its three years
> : old it supposed to skip. They all skip after a year or so. What you
> : need is an Alignment and Cleaning."
> Hmm wonder what that is .. know this behaviour! My Sony D-100 is now in the
age
> of four - and skips ...
Well, I've got a 7 year old D4 that has tens of thousands of play hours
and still plays as well now as it did when it was new. I don't know about
current models, but sony cd players of the D4 vinatge had a worm screw
that controlled the head movement during play. If this worm screw got
worn or dirty, the head would stick. If your model is similarly designed,
you could try cleaning and possibly lubing the worm screw.
George
--
George A. Durden
.5K EX Pilot
Unix Mercenary
DoD #0039 "No Risk, No Rush" CMRA #106
Gerd Truschinski
Yesterday was the first day I have read this group and this posting too.
In the evening I open my CD player, not working for 2 month. I saw the
screws mentioned in an earlier posting and said to the player that
I now start to turn them around. But first I will take a _last_ test.
AND it was working.
Conclusion: read s.e.
talk to your CD player
there had to be some sort of A.I. in this player
Thank you to the people giving the hint with the screws.
/gT/
Jim Duncan
>Hmm wonder what that is .. know this behaviour! My Sony D-100 is now in the age
>of four - and skips ...
Eventually, the little lens that reads the CD get dusty/dirty. Whenever
I start to have this skipping problem, I just carefully clean the lens
with a Q-Tip and plastic safe solvent. One could probably use rubbing
alcohol as with cleaning heads, etc.. Look under what would be the CD
playing position in the machine, and you'll see the little lens. Don't
muscle it too much with the Q-Tip.
--
KUFX | w ["] | WA6MBV
94.5 |... |___|_____..dun...@ravel.ati.com | Jim Duncan
FM | H | ----------
******** \_____I_____/ 37 3 10N/121 59 10W **************
John Nall
This has been somewhat of an interesting thread, and glad
to hear how it came out.
Remember, when opening up an unfamiliar piece of equipment,
and randomly adjusting screws, that there are several MurphyLaw
Corollaries which apply:
(a) The adjustment screw you turn will never be the
right one.
(b) However, it will be something absolutely crucial
to the correct functioning of your equipment.
(b) Once you move it from it's original position, you will
never be able to get it back there, no matter how much
you try.
:-)
--
John W. Nall | Supercomputer Computations Research Institute
na...@mailer.scri.fsu.edu | Florida State University, Tallahassee, Florida
Jeff Dairiki
Here's the long awaited followup regarding the many and
varied responses which I recieved regarding how to fix
a skipping CD player (and other random questions...)
How to fix a skipping CD player:
The first responses which I recieved said, basically, "Go get a book,
and read it." (This is of course, in my slothfulness, what I was
trying to avoid.) Nevertheless, I did go down to the used bookstore
and bought an eight year old book on CD repair. After an hour of
careful skimming, I attained the following enlightenments:
o CD players are complex and dastardly instruments containing
(as also pointed out by one respondent) at least four servo loops.
There's a focus (lens up and down) servo, a fast tracking (lens
radially in and out) servo, a slow tracking ('sled' in and out),
and a spindle drive servo.
Being a trained EE, and having been tought all the theory about
feedback amplifier in school, and having studies linear and non-linear
control in graduate school, I know _The Truth_ about servo systems:
they may be simple on paper, but making them work involves much
black magic.
o There are lots of pots and screws to turn and play with.
o The problem is most likely not in the power supply.
In a related vein, it was suggested I obtain a service manual for my
CD player. I ordered one from Sony. It's gonna cost $10.00. I
haven't seen it yet.
A couple days later, more practical advice started arriving.
Several people have suggested cleaning the lens. Despite the warning
printed in my player ("Never, never touch the lens" -- with international
symbols saying same...), the general impression is that this is a
regular (sometimes glass, sometimes optically coated, sometimes plastic)
lens which may be cleaned using standard methods. Like says, lens paper
and lens cleaning fluid, or Q-tip and distilled water, or soft cloth
and alchol, etc, etc... -- someone said that lens cleaning fluid is
a mix of ether and alcohol. One should take proper precautions to avoid
scratching the lens, or damaging the optical coating -- one should
also not munge to heavily on the lens -- as it is delicately suspended
on some sort of spring, and is directly driven by _two_ servo control
systems. (See black magic, above.)
I have of course (despite the sign in the CD player) been trying this
remedy periodically for the two years that my CD player has been skipping.
It hasn't been helping.
Many people reported that the main cause of CD skippage is dirty grease
in the 'sled' transport system. They suggested cleaning and re-lubing
the rails that the optical mechanism sled moves on, and the worm screw
(or rack-and-pinion as in my CD player) too.
So, I went home to clean and lube.
I opened up the CD player (it took awhile, these portable CD players
are tricky to disassemble, all sorts of hidden screws and clips...).
I found the rack-and-pinion mechanism and played with it for awhile.
Sure enough it seemed to be sticking. As I'd turn the drive mechanism,
the sled would move in fits and starts...
By the time I had it apart and cleaned (I cleaned the workings with
alcohol and kleenex) it was starting to get late. I dug around in my
tool supply to find my light machine oil, and found that I couldn't
find any; so, not wanting to leave the thing in pieces overnight, I
applied some 'Tri-Lube' (some kind of silicon goop I use on my sailboat
hardware...) and buttoned 'er back up.
Put in a CD (I picked the one which skipped the worst -- there are
some tracks on it which skipped so badly, I hadn't even had a chance
to listen to them yet...) ... Wow it works! Whattaya know.
A couple hours later, my listening glee was interrupted by a single
innocuous skip. I wasn't even sure it had skipped (I've become
acclimatized...) Later it skipped a couple more times. "Well,
It's much better than it was. I can live with it", says I.
Next day, get home, pop in "The Incredible Jimmy Smith", turn up the
volume, crack a beer... Ahhh....
After 10 seconds of cool blues, the CD goes into rapid skip,
auto scramble play mode. Worse than ever. Eyow.
Well, I figure I used the wrong grease... I plan on recleaning
and re-re-lubing again.
In the mean time, more suggestions have arrived.
Many suggestions involve twiddling pots and/or screws randomly.
I have a friend who did this. He had some brand-X CD player which
started skipping. He opened it up and twiddled the five pots he found
randomly until it started to work again. He says that he did this
several times, and each time his tuneup would last a month or so
before the skips started in again... He finally gave the unit to his
dad.
One respondant reports that one skipping CD player which didn't
repond to lens cleaning, or to rail cleaning, was succesfully fixed
by adjusting the little setscrew on the sled which tilts the lens
assembly.
Another suggestion was that the 'tracking sensitivity' pot was the
one which needed adjustment.
From what I can tell from my obsolete CD repair book, the pots all
adjust various servo loop gains and offsets -- maybe one of them
adjust the laser-diode output level,... In my unit I found six
trimpots, one setscrew, and one trimcap; none of the adjustments is
at all labeled. Figuring that a random walk in 8-space is is doomed,
I have decided to wait until my repair manual arrives before venuring
into this maze.
There were other suggestions.
Turning the player on its side seems to have worked for some. (I
had already tried rotating my player -- upside-down worked best for
me, but the improvement was minor...)
One fellow suggested that verbal threats to the CD player might work.
They didn't for me...
Despite the fact that my CD player still doesn't work, I was very
impressed by the quantity and quality of responses I recived to my query.
My gratitude extend to all who have responded, and all who have yet to
respond.
I will let y'all know if I ever get my CD player working...
Thanks Again.
Jeff.
PS As for my other questions, regarding just what in bean city is a
one-bit D/A, and what 8x oversampling means, I recieved several helpful
replies. Here are some edited replies -- I hope I don't offend anybody
by including your name to give you credit:
Regarding 'oversampling':
From Clifton Koch:
It all has to do with digital filtering of the output and aliasing. If
you sample a 1Khz tone at 20Khz, there would be no diffence in the digital
samples between the 1Khz tone and a 11Khz tone due to aliasing, so components
of both tones would be there on playback. With a CD sampling at 44.1 Khz,
aliasing starts at 22.05Khz, so you have to filter everything out of the D/A
converter above that mark. To get the 20-20Khz bandwith we want for music,
it takes a mighty steep analog filter to do the job, which has a lot of bad
side effects.
In comes digital. Oversampling to a digital filter merely means using the
same data multiple times on a digital filter. It doesn't seem like this will
do much usefull, but mathematically, it does. It moves the aliasing region
out by a multiple of the oversampling, allowing a very shallow analog filter
to do the anti-aliasing filtering. That's what they mean by X times
oversampling. The greater the number X, the less of an analog filter you need.
From Dave Platt:
The digital signal coming off of the CD must be filtered before it's
played back. Older CD players do all of this filtering in their analog
electronics, using a "brick wall" filter... these are expensive and
tricky to design. More recent CD players do some of the filtering using
digital electronics... they pre-smooth the signal using digital math by
creating "extra" samples (something like interpolation, although the
math is different) and then feed both the original and "extra" samples
to a DAC which is running several times faster than normal (e.g. 8
times faster). The output of the "oversampled" DAC must still be run
through an analog filter, but the filter's design is much less complex
(and is hence less expensive) than that of a "brick wall" filter.
Finally, Hendrik Boshoff give this user friendly description:
Sampling may be modelled as multiplication of the signal and a periodic
series of deltas in the *time domain*. The transform of the signal is
bandlimited. The transform of the delta-series is another delta-series.
Multiplication in time maps to convolution in frequency. Therefore, the
transform of the sampled function is an infinite repetition of the
spectrum of the original signal.
You don't want to sample too fast, then you must store too much data.
Nyquist says you don't want to sample too slow, then the repeating
spectra start overlapping and therefore distorting the baseband one
you're interested in. So you sample at 43.1 kHz for a signal limited
to approximitely 20 kHz.
Having a perfect low pass filter at your disposal, recovering the
original signal from the samples requires just filtering. But real
filters are difficult to tune accurately and don't easily attenuate
60 dB in 3 kHz if cut-off is at 20 kHz.
Now for the trick: Before the D/A-stage, numerically interpolate
the samples. An easy way is just to add a sample between each
existing pair, with value their average. Do this two
times more, and you have 8x the number of samples you started with.
This does not add any information to the sampled signal (thank heavens).
So what does it do? In the frequency domain, the original band-limited
spectrum is still there. The replicas however, have shifted up in
frequency. The first one sits around 345 kHz. So you have from 20 kHz
to 325 kHz to allow your filter to cut off. This is very easy, and you
can use a sloppy and cheap filter without getting unwanted high frequency
components.
As for what a one-bit A/D is, it seems to be some kind of fancy PWM like
scheme:
Clifton Koch says:
1 bit D/A is another method of oversampling. Instead of PCM as an output,
you do what is called delta-modulation. Each output sample has a value of
1 or 0, meaning the voltage should go up or down. If you do this fast enough,
you get a very close approximation of the original wave, with very little
antialiasing circuitry needed because of the high clock rate. 1 bit D/As
usually operate well into the MHz, so the filter for above 20Khz is usually
on the order of a single 15pf capacitor.
Dave Platt says:
One-bit and low-bit DACs (such as MASH and Bitstream) are less expensive
to manufacture than multi-bit (14-, 16-, 18- or 20-bit) DAC. They use a
low-resolution, but very precise DAC, running at very high conversion
rates (millions of times per second) and some sophisticated digital
filtering. Multi-bit DACs use a high-resolution DAC running at a slower
speed (tens or hundreds of thousands of times per second). It's cheaper
to build a "narrow, fast" DAC than a "wide, accurate, medium speed" DAC.
There are still quite a few people who believe that a well-designed
(high linearity) multibit DAC sounds better than a fast 1-bit or low-bit
DAC. In general, I believe that there's no general answer to the
question... there are good-sounding and bad-sounding CD players of both
types.
In effect, a 1-bit or low-bit converter takes this [the oversampling]
process to an extreme... it does almost all of the filtering using
digital mathematics, uses a _very_ fast converter (the equivalent of
256x oversampling, or even more) and then uses a simple one- or
two-stage analog filter.
(End of quoted materials)
So it seems to me that the new 'one-bit' CD player technology is just a
cost cutting measure and provides no increase (though probably no
decrease in audio quality.)
It has also been clarified that neither oversampling or one-bit A/D's
have anything to do with error correction schemes, or (of course) the
quality of the transport and optical stuff. Therefore this information
is of no use in selecting a new CD player which is less prone to slip.
Evidently, Sony has a new portable (D-515, I think?) out which has
enough RAM inside to buffer about three seconds worth of music. Thus it
should be able to skip for three seconds before the listenters pleasure
begins to suffer. This new unit is obviously the most expensive that
money can buy...
Thanks Again to all past and future respondents...
Jeff
dai...@u.washington.edu
--
-----
==>{ Jeff Dairiki (KI6MO/7) } University of Washington
{ dai...@u.washington.edu } Applied Physics Laboratory
{ (206)543-6262 / 543-1399 } 1013 NE 40th St; Seattle, WA 98105
J-F Bissonnette
> and still plays as well now as it did when it was new. I don't know about
> current models, but sony cd players of the D4 vinatge had a worm screw
> that controlled the head movement during play. If this worm screw got
> worn or dirty, the head would stick. If your model is similarly designed,
> you could try cleaning and possibly lubing the worm screw.
>
> George
Well perhaps someone can tell me what my problem is. I got a 2 years
old Luxman and it still plays fine, no skiping.... except one
one song and it on one of my favorites. When I first had this CD,
it was'nt skiping at all, but since a few weeks, on that song, it
skips. It does'nt seem like theres any damage on the CD itself.
Does anyone have an idea of what is going on in that case?
Thanks!
J.F.
--
ato...@geloser.login.qc.ca
Gentleman Loser System -- Montreal, Qc, Canada
William Stuart
>dai...@milton.u.washington.edu (Jeff Dairiki) writes:
>: If this is a FAQ, I have been naughty. I'm very sorry.
>:
>: So I've had this Sony Portable CD player for three years or so. When
>: it was about a year old it started to skip occasionally. Now it skips
>: all the time, and its really getting too annoying to ignore.
>: (It really wasn't very mistreated either -- it's been lashed down tight
>: in a clean dry corner of my sailboat the whole time...)
>:
>: So all the salepeople (can you really call them people?) at the stereo
>: stores around here say: "Oh yeah, of COURSE it skips. If its three years
>: old it supposed to skip. They all skip after a year or so. What you
>: need is an Alignment and Cleaning."
>Hmm wonder what that is .. know this behaviour! My Sony D-100 is now in the age
>of four - and skips ...
>First I thought the CD is bad but meanwhile it skips on new CDs too!!
>I thought that's the weak errorcorrection that the early little dingies
>had. I still have no answer ..
>I'll follow this thread.
>--
>Michael Zacherl, Wang Austria Ltd., Vienna |
>E-MAIL: m...@pag.wang.co.at | "Proof your chances,
>PHONE: +43 (1) 89-111 ext. 433 | and leave them or not."
>FAX: +43 (1) 894-17-14 |
Here it comes... SUPRISE!! ANYTHING made by Sony that has linear tracking
whatever WILL fail in short order. I am not sure why, but sony can't
make a linear tracking device for sh*t. I have had a turntable, 2 portable
CD players, and a 3.5" disk-drive. ALL have failed at least once. All had
Sony's worm-geared linear tracking. BAD design. OK, off the soapbox...
If the CD player is of the D7 or D55 variety, then it is almost certainly
the linear drive worm gear. On one of my units, the brushes in the motor
got warped and the motor wound up with a dead spot. After pulling the
motor apart and cleaning/bending the brushes, the thing has worked fine.
I did the fix about 2 years ago, no probs yet. Opening the unit and
yanking the motor is not hard if you have some _small_ tools, patience,
and mechanical skill.
The second CD, which I bought dead to canibalize for the other player, had
a slipped spindle drive gear. This can also cause skipping. Again, this
is a mechanical problem that can be fixed with glue if you feel confident
in your skills. The tracking motor had a failure identical to the one
above 6 months later. Same fix, no probs since.
In summary, it's probably the linear tracking mechanism. They are fairly
easy to fix if you have some tools, skills, and patience. If it is not
the linear mechanism, it is still most likely a simple mechanical problem.
'Alignment and Cleaning' sounds like a rip-off to me. The things are
supposed to align themselves. I have never had a player aligned or cleaned
and they are going on 8 years without it.
Just my $0.02
-Bill KD4GKK
stu...@ee.fit.edu
Kevin Lu
I've develop a scratch on one of my CDs and now the CD player doesn't play
one track correctly (i.e it skips, but only on that track on that cd). I
though these things were supposed to be durable!. SO whats the story?
+----------------------------------------+-------------------------------+
| Kevin Lu | Monash University |
| Email: kev...@yoyo.cc.monash.edu.au | Clayton, Victoria |
| | Australia |
Grant Thoms
I had a cd that jumped slightly on one of my fav songs, I gave it a good
polish (from the centre out) and it came right, sometimes you can
Polish out the scratches and it helps..
--
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Grant Thoms (Zoltar) Co-Sysop of `Silent Imperium' BBS
// Zol...@Glasgow.Amigans.Gen.NZ
\X/ ----
Standard Quote: `Insert $10 for the next 0.5 seconds'
*** Opinions expressed are my own ***
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
Chandra Bajpai
I too have a old (1988) Sony Portable Discman. My player are a stranger
problem - It loses tracking. But, only after it has been used for a while
(30 minutes, or less on a hot day). It will then not seek to a specified
track, or if it does if a track it will play with a weird sandpaper like
rythmic sound in the background.
I brought it down to a CD repair place thinking all it needed was
an alignment. The guys gave it back to me, saying the laser in the
unit was "weak". He claimed the new laser mechanism would be over $150, so
it would be better to get a new player. I really don't have alot of confidence
in this diagnosis.
I have never heard of a weak laser. I am capable of fixing (or at least trying)
the mechanism if I had some pointers. Are any of the adjustments in the
PCB for the laser signal strength? Did this guy make a correct diagnosis?
Thanksfor all your help,
Chandra Bajpai
top...@brandeis.cs.edu
Joern Yngve Dahl-Stamnes
>Speaking of CDs, just HOW durable are they?
>
>I've develop a scratch on one of my CDs and now the CD player doesn't play
>one track correctly (i.e it skips, but only on that track on that cd). I
>though these things were supposed to be durable!. SO whats the story?
I also got a CD with a scratch that make my CD sk-sk....ski...skip.
Someone have told me that there might be some cure for the CD, but I
have never find any cure for the CD. Does anyone know if there is any
cure? What about heating the CD up a bit for a long time hoping that the
scratch edges get rounder and perhaps make the scratch smoother so that
more information become readable again?
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+
* I went back to my mother, * Joern Yngve Dahl-Stamnes *
* I said, "I'm crazy ma, help me!" * University of Trondheim *
* She said, "I know how it feels son, * The Norwegian Institute of Tech. *
* 'cause it runs in the family." * Division of Physical Electronics *
* - The Who, Quadrophenia * e-mail: da...@fhydra.dnet.unit.no *
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+
Jeff Dairiki
Thanks Again.
Jeff.
Regarding 'oversampling':
From Clifton Koch:
From Dave Platt:
Clifton Koch says:
Dave Platt says:
There are s
* Origin: The Electronic Mailbox (1:348/7.0)
Jeffrey Mulligan
brand new. I got it serviced under warranty, but had just moved and
didn't set it up for a while. When I finally did, I discovered that
the skipping was better, but still occasionally skipped. Interestingly,
it seems to skip more when the unit is cold, that is, it will skip
a lot when first turned on on a cold morning, but after an hour
or so it may play the same disk without skipping.
Having been disappointed with the "authorized" service, I will be interested
to hear any more suggestions about how to fix this.
--
Jeff Mulligan (j...@eos.arc.nasa.gov)
NASA/Ames Research Ctr., Mail Stop 262-2, Moffett Field CA, 94035
(415) 604-3745
Keith Drescher ip30
It did solve the intermittant tracking problem that I've been having
for a quite some time now.
But a caveat:
I found a book on CD repair that tells how to do it right -
so next week I'm going to put a scope on the thing and adjust it
to spec. I read the book and decided that adjusting the tracking
control by the "guess" method wouldn't do any harm, just maybe put
my CD player out of comission until I could get a scope home.
A CD player is a fairly complex item though, there is the real chance
just twiddling any pot you happen to find might cause more harm than
good - be forewarned.
Keith Drescher
Bob Haar
|>I adjusted the tracking control on my 6 year old JVC unit last night.
|>It did solve the intermittant tracking problem that I've been having
|>for a quite some time now.
|>
|>But a caveat:
|>I found a book on CD repair that tells how to do it right -
What book? And where did you find it?
|>so next week I'm going to put a scope on the thing and adjust it
|>to spec. I read the book and decided that adjusting the tracking
|>control by the "guess" method wouldn't do any harm, just maybe put
|>my CD player out of comission until I could get a scope home.
|>A CD player is a fairly complex item though, there is the real chance
|>just twiddling any pot you happen to find might cause more harm than
|>good - be forewarned.
Maybe so, but the risk seems worthwhile to me. I got quotes from
several audio repair shops for a CD player that skips on the first
track (directory?) read - they varied from $65 to $95 just to brin the
unit into the shop and more if they had to take it apart. I so one
survey that said the average repari cost for a CD player is $170.
For a unit that cost $200 originally, I'll risk breaking it.
---
Robert Haar InterNet : rh...@gmr.com
Computer Science Dept., G.M. Research and Environmental Staff
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.
Mike G. Hoffberg
>
>But a caveat:
>I found a book on CD repair that tells how to do it right -
>Keith Drescher
(since e-mail seemed to bounce)
What is the name of this book, and where do I find it?
MIKE
--
Michael Hoffberg /.\ <Build APS> "Jeez, am I the only ~\ /~
hoff...@phebos.aps.anl.gov // \\ Argonne one who paid full \ /
hoff...@anlaps.aps.anl.gov //_O_\\ National price?" F.F. |
/__| |__\ Lab Obbyn! Obbyn! _|_
Jimmy Liberato
>Thus spoke the keyboard of kev...@yoyo.cc.monash.edu.au (Kevin Lu):
>>
>>I've develop a scratch on one of my CDs and now the CD player doesn't play
>>one track correctly (i.e it skips, but only on that track on that cd)...
>
>I also got a CD with a scratch that make my CD sk-sk....ski...skip.
>Someone have told me that there might be some cure for the CD...
Go to to a auto paint supply store and get the finest wet/dry sandpaper
they have (the kind for rubbing out lacquer, something like 1200).
Carefully sand radially (across tracks). Finish with Glass Wax. Of course
it is probably not worth $15 of your time to do all of that!
--
Jimmy Liberato libe...@dri.com
...uunet!drivax!liberato
Michael Covington
Innnnteresting! Sounds like a way to get rid of scratchy surfaces on
old surplus meter faces. I'll have to try it (on meters, not on CDs...)
--
:- Michael A. Covington internet mcov...@uga.cc.uga.edu
:- Artificial Intelligence Programs phone 706 542-0359
:- The University of Georgia fax 706 542-0349
:- Athens, Georgia 30602 U.S.A. amateur radio N4TMI
Hans
>In article <BFGR...@dri.com> libe...@dri.com (Jimmy Liberato) writes:
>>Go to to a auto paint supply store and get the finest wet/dry sandpaper
>>they have (the kind for rubbing out lacquer, something like 1200).
>>Carefully sand radially (across tracks). Finish with Glass Wax. Of course
>>it is probably not worth $15 of your time to do all of that!
>
>Innnnteresting! Sounds like a way to get rid of scratchy surfaces on
>old surplus meter faces. I'll have to try it (on meters, not on CDs...)
Gee, I'd just use Brasso. No wax necessary, you can get it at the
grocery store, and it's a lot less than $15.
>:- Michael A. Covington internet mcov...@uga.cc.uga.edu
-hans
--
Hans-Gabriel Ridder Digital DECwest Engineering
rid...@rust.zso.dec.com Bellevue, Washington, USA
{pacbell,pyramid,uunet}!rust.zso.dec.com!ridder
Keith Drescher ip30
>In article <1992Oct2.152431.10629@ip29!bob> kad@ip29!bob (Keith Drescher ip30) writes:
>>
>>But a caveat:
>>I found a book on CD repair that tells how to do it right -
>> ^^^^^^^^^^^^^^^^^
>>Keith Drescher
>
>(since e-mail seemed to bounce)
>
>What is the name of this book, and where do I find it?
>
will end any further postings for the book name.
The name of the book is:
Title: Troubleshooting and repairing compact disc players.
Author: Homer L. Davidson
Publisher: TAB
There are copies at several local libraries here, but since it's a TAB book
many small electronic stores tend to carry TAB books in my experience. Also
find any TAB book and the last page usually lists other available titles
and tells how to order them direct from the publisher. The book covers
several older models of CD player and was published in 1988.
Iain D. Holness
bounced back for me as well.
Even an ISBN number would be appreciated :)
Iain