10 lý do tại sao đầu đọc không thể đọc đĩa & cách xử lý

Ducanh2002hv · 22/2/16

Em có con cdp 333esj mấy hôm nay bỏ đĩa vào thì vẫn nhận và đọc được tổng số track và thời gian. Nhưng khi bật play thì lại không chạy, một lúc sau thì báo no disk. Các bác bắt bệnh cho e với, tiện cho e hỏi ở HN có chỗ nào sửa đầu cdp uy tín không ạ.

neckosky · 17/4/16

Mình có cái CDP Sony-V715 nó không nhận được bài, bật lên cho đĩa vào nó quay chừng 3s thì dừng, giống trường hợp số 7. Em cũng đã kiểm tra hệ cơ, không thấy vấn đề gì, mong các cao nhân chỉ giáo ạ.

thanhtu77 · 18/4/16

em đốt đèn tìm đỏ con mắt mới mua được mắt sony KHM 220AAA về thay . mà nó vẫn bị. quay đĩa 1 xíu lại nodis.

neckosky · 18/4/16

Ha ha...loay hoay mãi và kết luận như sau: Chỉnh chiết áp gần mắt thì sẽ chỉnh được đĩa có quay và không quay. Khi nó quay rồi thì chỉnh cái chiết áp RV105 theo chiều kim đồng hồ 1 chút thì nó nhận đc bài ngay, và rất nhanh. Cơ mà thấy cái con IC LA6520 nó có vẻ nóng lạ thường, sờ khoảng 5s là phải bỏ ra ko bỏng. Các bác cho em cái y kiến. Dù sao thì bây giờ em nó cũng hoạt động rồi, tính gắn cho IC này cái tản nhiệt.

neckosky · 26/4/16

Các bác cho mình hỏi, trên main của cdp có con này, mà không hiểu là con gì. Mình nghi là con diode hay fuse, nhưng ko biết có phải ko.

vinhlottery · 9/5/16

Mình có con CDP Maranzt 19F, dạo này nó bị bệnh lạ là buổi sáng thì không đọc được CD nhưng từ trưa trở đi thì lại đọc tốt. Nhờ các cao thủ đoán bệnh giúp và nếu trường hợp mắt em này cần thay thế thì có dễ tìm không.

cutrongminh · 21/7/17

tamtam said: ↑

Vừa qua, sau khi chạy rà em Esoteric X10W sau khi thay tụ, đầu đĩa em lại không đọc được đĩa xịn. Lọ mọ vệ sinh mắt rồi cân chỉnh và đọc tài liệu trên mạng, em phát hiện ra trang web tuyệt vời này phát hiện bệnh về mắt và cách cứu chữa bao gồm cả hình ảnh. Mời các Bác cũng tham khảo:

http://www.lampizator.eu/LAMPIZATOR/TRA ... ology.html

Trích đoạn dưới đây hy vọng giúp các Bác nào bị đầu CD vật khổ sở như em.

Laserology

Some thoughts about laser failures that never happened.
And about those that did.

Hey, do you know where I can buy a new laser for my CD? It just died.
I heard it so many times that I decided to write about lasers, their problems and easy fixes.

I looked inside over 100 CD players which DID NOT READ the CD anymore and only one (in decimal and binary mode it is 1) had failed laser. And that one was dead because of my stupidity. But it (my stupidity) is not the subject of this article.
Other peoples stupidity is.

Anyway, what happens is that there is probably 20 different reasons why the CD player does not read the disc, and people have such strong prejudice that they all call these failures DEFECT LASER.

This is CRIMINAL because lasers are not produced anymore, and the scarce resources left, the holy reserves - are brutally cannibalized by people who know no better and simply buy the new units.

The top ten reasons why CD's are not read - according to "my vast experience" in that matter - are:

1. There is a CD disk inside the player as resulting from moving to a different house with the disc left in the drawer. Disc falls out into the guts of the CD player and blocks the mechanism. When the owner puts second disk afterwards - the player rightly displays ERROR.
- remedy: the first cure that springs to my mind is - open the CD and remove the stuck CD.

2. The 20 year old belt that powers the drawer starts slipping or breaks. After closing the drawer - CD is not properly positioned on the spindle.
- remedy: replace the belt

3. The CD player was being used in a dusty environment and the dust or cigarette tar settled on the laser optics. Dust causes beam dispersion. Laser looses focus.
- remedy: open the player and clean the laser surface with a Qtip. First- with wet tip dipped in the window cleaning liquid, then - dry one.
If this is not enough - clean the laser INSIDE the reading head. This is for advanced people. Better to give this job to a watch repair man. See below - some pics.

4. The power supply of the laser circuit is defective: either too low voltage, or noisy, or starts oscillating from poor filtering or regulation. The cause may be dried out electrolytes.
- remedy: replace all electrolytes in the digital part of PCB, or better - all of them.

5. There is a cold joint in the laser circuit.
- truth is that the solder joints do corrode and do fail. Our best players are 20 years old and this shows. A joint which is hot, like a leg of a regulator, or a point where the raw supply is rectified, or a laser power controller - from the heat they develop accelerated deterioration - mixture of oxidation, flux burning, and tin evaporation.
- remedy - look at all solder joints, especially around laser cable connectors, around all regulators, around places that look toasted, brownish or cooked - and re-solder these points adding a bit of fresh solder with fresh flux.

6. Moving cables - or ribbons - do get broken after a million bends.
Check for continuity in flexing ribbons leading to the laser, the drawer, the motor or the tracking mechanics.

7. The tracking mechanism accumulates dirt, hairs or dust on the greasy part and the tracking can not arrive at the center-most starting position. With every ride of the tracking - the dirt is pushed away and forms a sort of a "bumper" that stays on each side of the shaft.
- remedy: clean the tracking shafts, axis and rods at their extreme ends.

8. The main motor is not keeping the right speed.
- it will look like the laser can't read, but it is simply the wrong rotation speed. May be caused by CD slipping on the spindle, or motor defect, or something blocking the CD like audible friction against the surface of the drawer. For instance - the spindle can wear off its bottom bearing and the whole CD will be lower by 1/10th of mm. The laser will loose focus and the top clamp will not press hard enough. In any event - the spindle must be brought back up this 1/10th of mm.
- remedy - if the motor is just a normal Mabuchi for 5 bucks - replace it. If it is a CDM or KSS Magnetic series with brushless motors - just adjust the spindle height.

9. There is a hair or something else inside laser focusing mechanism
The laser can't freely move up and down. Since CD is strongly electrostatic - it attracts hair, dust and animal furs. During playback - these can get caught under laser focusing suspension.
- remedy - remove the obstacle.

10. The CD does not spin.
After closing the drawer nothing happens and defect is displayed. It maybe just the result of not spinning at all. The CD behaviour must be observed - so the top cover must be removed.

CD laser diagnostics - a quick guide
Is CD laser really dead ?
Without specialized equipment we small mortals can diagnose the problem pretty well and save tons of money on service.
Or even new laser purchase. Or even a new player.

1. Open the player's hood

2. Put the original factory made CD with clean surface and press drawer CLOSE button.

3. Does the drawer close fully?

4. If 3 is yes, then does the CD spin at all?

5. If 4 is yes, does it spin for 2-3 seconds or for over 10 seconds? Does it spin VERY FAST like crazy or with somewhat controlled speed ?

6. If the 5 answer is - controlled speed and 2-3 seconds - the laser is alive and it can detect the beam reflection from silver surface.

Tips: if the laser is dead, the CD will not spin at all. The CD motor has a signal to start spinning only after the laser heads reports: "reflective surface detected on the height where CD is expected to be ". However, as someone rightly pointed out, some servo mechanisms will try spinning without checking if CD is in place or not. Apparently, they made assumption that a small motor spin in vain will not hurt.

7. Does the display show after 3 s of spinning the correct number of tracks and time ?
If the CD was spinning but can not show time - it means it could not read the TOC - famous Table Of Contents. So the laser head was seeing the disc surface but could not read the first line of data. This first line is at the very center of CD disc, so the tracking of the laser assembly must be on position "center most". The inner-most position. So if we have a tracking problem - we cant move to the very center and TOC cant be read.

8. If the TOC is displayed correctly but the PLAY does not happen - it means that:
- laser is OK
- TRACKING does not move the laser from first "groove" of the disc to another. Then go down to tracking problem chapter.

9. The CD starts to play, but skips
- observe if it skips forward or backward. If there is a mechanical problem - the advance of tracking is blocked - the skipping will happen backward. If the tracking controller is too enthusiastic - it will skip forward.
Adjust the physical levelling of the CD player, and adjust the tracking gain (see below).

10. The CD plays well the factory CD's but fails on the CD-R's
The laser focus on CD-R is different than in factory CD. The pit reflection is also different on these two CD media
The amount of plastic film that protects the metallic layer in the CD and CD-R is very different.
Generally, it is always easier to read the CD than the CD-R, no matter how good is the blank media and how slowly it has been recorded. Not to mention the no name CD-R recorded at 24x.
So if the normal CD plays well and the CD-R plays faulty (distorts, skips a lot, reads slowly or not at all) there is probably a problem on the horizon. The system is already too weak for CD-R but still somehow manages on regular CD's.
This common problem can be a result of any other problem listed above - dirty laser, bad adjustment, worn out spindle, slipping disc, slipping belt, anything really. INCLUDING of course - a dying laser. All slowly building-up problems show on CD-R's first, months before CD's will show same problem.

Problems 9 and 10 usually get worse as the laser is further away from the center - meaning - on higher number of the tracks. If it starts skipping on track 4, it will probably very badly skip on track 10th and never ever reach track 12th.

11. Lasers which die on players bought 2 weeks ago from E-Bay
If the otherwise excellent, pretty and valuable mint player starts having laser problems at the original owner, it will inevitably end up in the hands of the laser guru, who will turn up the power of laser emission. It may help the laser to read better TEMPORARILY.
Then the guru gives the player back to the owner and says: " well, I managed to help you, the bill is 200 Euro, but take my good expert advice and start looking for a new player. This one will not last long. Sell it quickly, while it still works okay.
Then the owner goes home, and he freaks out. Gee, if the adjustment costed me 200 Eu, how much is gonna be next time around, when the big un strikes ? So he puts it on ebay with a story attached about the uncle who passed away and while the nephew was cleaning up his house this cd player was found. (Funny that these houses always get cleaned by the nephews not sons or wifes) It was always well taken care of because the uncle was a music lover. He only listened to it occasionally - one opera CD every sunday after a mess. It is sold as it is, without warranty, because the young nephew is too busy to check it. "
That is how mint collectors players end up in the hands of happy new owners only to die 2 weeks later.
If that story is familiar to you - the laser is REALLY DEAD. A dying laser with cranked up emission will die very fast.
.

Hy vọng hữu ích.

Kính
Click to expand...

Cảm ơn thông tin bổ ích của bạn

makalixo · 22/6/19

Cd wadia6 của e bị hiện tượng chạy phono dc 7_8bài xong là ậm ừ vấp.cho đĩa ra thay đĩa khác thì ko nhận hoặc nhận thì nhảy nhanh như phi và phần nắp gần nguồn cắm dây thấy nóng.nhờ các bác trên chỉ giúp.thks

tepriu · 22/6/19

Mình nghĩ mắt mũi kèm nhèm rồi .cho đi BV mắt đi bác ơi

makalixo · 23/6/19

Thks Bác tepriu nhé.chắc cho đi viện mắt TW nào đấy mà e chưa biết tìm đâu doctor

tanthegioi · 19/7/19

Cám ơn các sếp nhiều ! Em cũng nghĩ lâu ngày nó bị bẩn thôi. Nhưng mà em cũng thấy lạ: Nếu bấm trực tiếp vào nút Open trên CDP thì không bị, dùng khiển thì thỉnh thoảng mới bị thôi. Có khi nào do tín hiệu từ remote yếu, chập chờn nên gây ra hiện tượng đó không các sếp

makalixo · 20/7/19

Có lẽ nào a/e chơi và học thêm nghề phụ các cụ nhỉ

khoanguyenhue · 27/7/19

Cái đầu cdp denon rồi marantz của em vào mùa mưa ẩm thấp ít dùng bị ẩm là đưa đĩa cd vào nó không chịu đọc. Để cdp chế độ On khoảng sau 1 vài tiếng nó nóng lên là đọc hết tất cả các đĩa. Nên kinh nghiệm khi nào vào mùa mưa là em cứ bật lên vậy khoảng 1 tiếng rồi tắt. Sau không còn bị nữa.

hoangdinhthu · 10/5/20

Em có con maranzt 80 vẫn chạy bt mà mất tiếng ko biết bị sao ạ các bác ?

Aone · 10/5/20

Bài này hay quá, cám ơn chủ topic!

mrsiro · 19/5/21

tamtam said: ↑

Vừa qua, sau khi chạy rà em Esoteric X10W sau khi thay tụ, đầu đĩa em lại không đọc được đĩa xịn. Lọ mọ vệ sinh mắt rồi cân chỉnh và đọc tài liệu trên mạng, em phát hiện ra trang web tuyệt vời này phát hiện bệnh về mắt và cách cứu chữa bao gồm cả hình ảnh. Mời các Bác cũng tham khảo:

http://www.lampizator.eu/LAMPIZATOR/TRA ... ology.html

Trích đoạn dưới đây hy vọng giúp các Bác nào bị đầu CD vật khổ sở như em.

Laserology

Some thoughts about laser failures that never happened.
And about those that did.

Hey, do you know where I can buy a new laser for my CD? It just died.
I heard it so many times that I decided to write about lasers, their problems and easy fixes.

I looked inside over 100 CD players which DID NOT READ the CD anymore and only one (in decimal and binary mode it is 1) had failed laser. And that one was dead because of my stupidity. But it (my stupidity) is not the subject of this article.
Other peoples stupidity is.

Anyway, what happens is that there is probably 20 different reasons why the CD player does not read the disc, and people have such strong prejudice that they all call these failures DEFECT LASER.

This is CRIMINAL because lasers are not produced anymore, and the scarce resources left, the holy reserves - are brutally cannibalized by people who know no better and simply buy the new units.

The top ten reasons why CD's are not read - according to "my vast experience" in that matter - are:

1. There is a CD disk inside the player as resulting from moving to a different house with the disc left in the drawer. Disc falls out into the guts of the CD player and blocks the mechanism. When the owner puts second disk afterwards - the player rightly displays ERROR.
- remedy: the first cure that springs to my mind is - open the CD and remove the stuck CD.

2. The 20 year old belt that powers the drawer starts slipping or breaks. After closing the drawer - CD is not properly positioned on the spindle.
- remedy: replace the belt

3. The CD player was being used in a dusty environment and the dust or cigarette tar settled on the laser optics. Dust causes beam dispersion. Laser looses focus.
- remedy: open the player and clean the laser surface with a Qtip. First- with wet tip dipped in the window cleaning liquid, then - dry one.
If this is not enough - clean the laser INSIDE the reading head. This is for advanced people. Better to give this job to a watch repair man. See below - some pics.

4. The power supply of the laser circuit is defective: either too low voltage, or noisy, or starts oscillating from poor filtering or regulation. The cause may be dried out electrolytes.
- remedy: replace all electrolytes in the digital part of PCB, or better - all of them.

5. There is a cold joint in the laser circuit.
- truth is that the solder joints do corrode and do fail. Our best players are 20 years old and this shows. A joint which is hot, like a leg of a regulator, or a point where the raw supply is rectified, or a laser power controller - from the heat they develop accelerated deterioration - mixture of oxidation, flux burning, and tin evaporation.
- remedy - look at all solder joints, especially around laser cable connectors, around all regulators, around places that look toasted, brownish or cooked - and re-solder these points adding a bit of fresh solder with fresh flux.

6. Moving cables - or ribbons - do get broken after a million bends.
Check for continuity in flexing ribbons leading to the laser, the drawer, the motor or the tracking mechanics.

7. The tracking mechanism accumulates dirt, hairs or dust on the greasy part and the tracking can not arrive at the center-most starting position. With every ride of the tracking - the dirt is pushed away and forms a sort of a "bumper" that stays on each side of the shaft.
- remedy: clean the tracking shafts, axis and rods at their extreme ends.

8. The main motor is not keeping the right speed.
- it will look like the laser can't read, but it is simply the wrong rotation speed. May be caused by CD slipping on the spindle, or motor defect, or something blocking the CD like audible friction against the surface of the drawer. For instance - the spindle can wear off its bottom bearing and the whole CD will be lower by 1/10th of mm. The laser will loose focus and the top clamp will not press hard enough. In any event - the spindle must be brought back up this 1/10th of mm.
- remedy - if the motor is just a normal Mabuchi for 5 bucks - replace it. If it is a CDM or KSS Magnetic series with brushless motors - just adjust the spindle height.

9. There is a hair or something else inside laser focusing mechanism
The laser can't freely move up and down. Since CD is strongly electrostatic - it attracts hair, dust and animal furs. During playback - these can get caught under laser focusing suspension.
- remedy - remove the obstacle.

10. The CD does not spin.
After closing the drawer nothing happens and defect is displayed. It maybe just the result of not spinning at all. The CD behaviour must be observed - so the top cover must be removed.

CD laser diagnostics - a quick guide
Is CD laser really dead ?
Without specialized equipment we small mortals can diagnose the problem pretty well and save tons of money on service.
Or even new laser purchase. Or even a new player.

1. Open the player's hood

2. Put the original factory made CD with clean surface and press drawer CLOSE button.

3. Does the drawer close fully?

4. If 3 is yes, then does the CD spin at all?

5. If 4 is yes, does it spin for 2-3 seconds or for over 10 seconds? Does it spin VERY FAST like crazy or with somewhat controlled speed ?

6. If the 5 answer is - controlled speed and 2-3 seconds - the laser is alive and it can detect the beam reflection from silver surface.

Tips: if the laser is dead, the CD will not spin at all. The CD motor has a signal to start spinning only after the laser heads reports: "reflective surface detected on the height where CD is expected to be ". However, as someone rightly pointed out, some servo mechanisms will try spinning without checking if CD is in place or not. Apparently, they made assumption that a small motor spin in vain will not hurt.

7. Does the display show after 3 s of spinning the correct number of tracks and time ?
If the CD was spinning but can not show time - it means it could not read the TOC - famous Table Of Contents. So the laser head was seeing the disc surface but could not read the first line of data. This first line is at the very center of CD disc, so the tracking of the laser assembly must be on position "center most". The inner-most position. So if we have a tracking problem - we cant move to the very center and TOC cant be read.

8. If the TOC is displayed correctly but the PLAY does not happen - it means that:
- laser is OK
- TRACKING does not move the laser from first "groove" of the disc to another. Then go down to tracking problem chapter.

9. The CD starts to play, but skips
- observe if it skips forward or backward. If there is a mechanical problem - the advance of tracking is blocked - the skipping will happen backward. If the tracking controller is too enthusiastic - it will skip forward.
Adjust the physical levelling of the CD player, and adjust the tracking gain (see below).

10. The CD plays well the factory CD's but fails on the CD-R's
The laser focus on CD-R is different than in factory CD. The pit reflection is also different on these two CD media
The amount of plastic film that protects the metallic layer in the CD and CD-R is very different.
Generally, it is always easier to read the CD than the CD-R, no matter how good is the blank media and how slowly it has been recorded. Not to mention the no name CD-R recorded at 24x.
So if the normal CD plays well and the CD-R plays faulty (distorts, skips a lot, reads slowly or not at all) there is probably a problem on the horizon. The system is already too weak for CD-R but still somehow manages on regular CD's.
This common problem can be a result of any other problem listed above - dirty laser, bad adjustment, worn out spindle, slipping disc, slipping belt, anything really. INCLUDING of course - a dying laser. All slowly building-up problems show on CD-R's first, months before CD's will show same problem.

Problems 9 and 10 usually get worse as the laser is further away from the center - meaning - on higher number of the tracks. If it starts skipping on track 4, it will probably very badly skip on track 10th and never ever reach track 12th.

11. Lasers which die on players bought 2 weeks ago from E-Bay
If the otherwise excellent, pretty and valuable mint player starts having laser problems at the original owner, it will inevitably end up in the hands of the laser guru, who will turn up the power of laser emission. It may help the laser to read better TEMPORARILY.
Then the guru gives the player back to the owner and says: " well, I managed to help you, the bill is 200 Euro, but take my good expert advice and start looking for a new player. This one will not last long. Sell it quickly, while it still works okay.
Then the owner goes home, and he freaks out. Gee, if the adjustment costed me 200 Eu, how much is gonna be next time around, when the big un strikes ? So he puts it on ebay with a story attached about the uncle who passed away and while the nephew was cleaning up his house this cd player was found. (Funny that these houses always get cleaned by the nephews not sons or wifes) It was always well taken care of because the uncle was a music lover. He only listened to it occasionally - one opera CD every sunday after a mess. It is sold as it is, without warranty, because the young nephew is too busy to check it. "
That is how mint collectors players end up in the hands of happy new owners only to die 2 weeks later.
If that story is familiar to you - the laser is REALLY DEAD. A dying laser with cranked up emission will die very fast.
.

Hy vọng hữu ích.

Kính
Click to expand...

Mở mang thêm kiến thức, thanks bác

hangtoan · 26/5/21

Bài viết chủ thớt hay và bổ ích lại dịch rất dí dỏm. Cảm ơn nhiều!

totorauxom · 19/2/23

Esoteric cái đĩa xanh không quay được nueax nhờ các bác giúp ạ

caicoc2004 · 18/7/23

neckosky cầu trì nhé

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