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A problem with a cd player

G

Gaetan Mailloux

Jan 1, 1970
0
Hello

A friend of mine do have a kenwood DP-460 cd player with a cd playing problem.

My friend was sure that the laser was burned, but I
decide to test his Kenwood cd player, wen I use commercial music cd it
work perfect, but wen I use burned cd-r music, this Kenwood cd player can
not play more than 7 track, after 7 track it do jerky sound with the
music, it look like it can not follow those track.

Any hints of what could be the problems ?

Here is a link to a part of the schematic of the kenwood DP-460 cd player.

http://img101.imageshack.us/img101/4599/kenwooddp460smallfy3.jpg

Thank

Bye

Gaetan
 
D

David Nebenzahl

Jan 1, 1970
0
A friend of mine do have a kenwood DP-460 cd player with a cd playing problem.

My friend was sure that the laser was burned, but I
decide to test his Kenwood cd player, wen I use commercial music cd it
work perfect, but wen I use burned cd-r music, this Kenwood cd player can
not play more than 7 track, after 7 track it do jerky sound with the
music, it look like it can not follow those track.

Any hints of what could be the problems ?

Here is a link to a part of the schematic of the kenwood DP-460 cd player.

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.


--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)
 
A

Arfa Daily

Jan 1, 1970
0
Gaetan Mailloux said:
Hello

A friend of mine do have a kenwood DP-460 cd player with a cd playing
problem.

My friend was sure that the laser was burned, but I
decide to test his Kenwood cd player, wen I use commercial music cd it
work perfect, but wen I use burned cd-r music, this Kenwood cd player can
not play more than 7 track, after 7 track it do jerky sound with the
music, it look like it can not follow those track.

Any hints of what could be the problems ?

Here is a link to a part of the schematic of the kenwood DP-460 cd player.

http://img101.imageshack.us/img101/4599/kenwooddp460smallfy3.jpg

Thank

Bye

Gaetan

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
 
A

Adrian C

Jan 1, 1970
0
Gaetan said:
Hello

A friend of mine do have a kenwood DP-460 cd player with a cd playing problem.

My friend was sure that the laser was burned, but I
decide to test his Kenwood cd player, wen I use commercial music cd it
work perfect, but wen I use burned cd-r music, this Kenwood cd player can
not play more than 7 track,

Try burning the CDs at a slower speed.
 
M

Mark Zacharias

Jan 1, 1970
0
Arfa Daily said:
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


********************************************************
Have you, as a first move, tried cleaning the lens ? (properly with alcohol
etc, not a cleaner disc).


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.
As you get further into a disc, its rotational speed falls to maintain
CAV.

Perhaps because audio CD's are CLV...

;-)


Mark Z.
 
W

William Sommerwerck

Jan 1, 1970
0
As you get further into a disc, its rotational speed falls to maintain
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).
 
S

Samuel M. Goldwasser

Jan 1, 1970
0
William Sommerwerck said:
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. :)

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
G

Gaetan Mailloux

Jan 1, 1970
0
Mark Zacharias" ([email protected]) said:
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.


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
 
N

N_Cook

Jan 1, 1970
0
Samuel M. Goldwasser said:
Nit picking. :)

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.


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

Any more nits?
 
A

Arfa Daily

Jan 1, 1970
0
Mark Zacharias said:
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.

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
 
A

Arfa Daily

Jan 1, 1970
0
William Sommerwerck said:
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).

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
 
A

Arfa Daily

Jan 1, 1970
0
N_Cook said:
Linguistically shouldn't it be "farther out of a disc",
further for time,
farther for distance.

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

Arfa
 
M

Mark Zacharias

Jan 1, 1970
0
Arfa Daily said:
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

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

mz
 
M

Mark Zacharias

Jan 1, 1970
0
Gaetan Mailloux said:
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


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.
 
A

Arfa Daily

Jan 1, 1970
0
I knew that you knew that. I was just foolin' around.

mz

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
 
M

Mark Zacharias

Jan 1, 1970
0
Arfa Daily said:
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.
 
W

William Sommerwerck

Jan 1, 1970
0
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...

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.
 
A

Arfa Daily

Jan 1, 1970
0
Meat Plow said:
Old age sucks.

Big time for sure. Thirty years ago, I thought I was immortal, and could
keep going for two or more days at a time without sleep. I just couldn't
figure how people could degenerate into the old farts that they did. Now I
am one, and I look at my daughter looking at me thinking "I just can't
figure ... "

Sigh ... :-\

Arfa
 
G

Gaetan Mailloux

Jan 1, 1970
0
Mark Zacharias" ([email protected]) said:
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.

Hello

I have an old Telequipment scope who goes up to 1 mhz, it should do the job.

I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF , TEOF

Wich one are for adjusting the Focus Offset ?

Thank a lot

Gaetan
 
M

Mark Zacharias

Jan 1, 1970
0
Gaetan Mailloux said:
Hello

I have an old Telequipment scope who goes up to 1 mhz, it should do the
job.

I've look on the main pcb and there is 4 trimpot; T.BAL , F.BAL , FEOF ,
TEOF

Wich one are for adjusting the Focus Offset ?

Thank a lot

Gaetan


FEOF should be the one, but a 1 meg scope won't really get it. You can
adjust for maximum envelope size, which probably is good enough, but you
can't look at the diamond shaped center area of the expanded "eye" pattern
as viewed on a 30mHz or higher scope. Sometimes a x10 probe is required, but
in my experience it is rare for a direct probe to load down this
measurement.

You can "Google CD eye pattern" and see what I'm talking about.

Mark Z.
 
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