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#1
Posted to rec.audio.tech
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QUESTION: Strange Yamaha CD Player Behaviour
I purchased a Yamaha CDX-710 CD player at a yard sale. It has new belts and plays and sounds great, BUT...sometimes a disc will skip badly. Since all of my discs are in mint condition, I knew it had to be the player. I opened the player up and discovered something. Take a look at this photo: http://i240.photobucket.com/albums/f...123/yamaha.jpg If I press down gently at the location indicated in the photo, the skipping stops immediately and the disc plays perfectly. I don't have to KEEP my finger there -- I simply have to press down on the part immediately above the center of the spinning disc, and everything sounds fine. HERE IS THE WEIRD PART: I have looked VERY CLOSELY at this spot, from all angles, when I press down. I CANNOT SEE OR FEEL ANY MOVEMENT. Nothing "clicks" into place or shifts into (or out of) position. I simply have to touch this spot and the disc no longer skips. Nothing at all seems to be mis-aligned or out of place. Sometimes the player plays discs perfectly, and I don't have to touch anything at all. But other times, when the disc player is skipping, all I have to do is touch the top of the disc clamp and everything is fine. WHAT IS GOING ON? What could possibly be out of place? If something IS out of place, it surely can't be by much. I can't stress enough that I cannot see or feel ANYTHING different when the disc is skipping OR when it has been corrected. I KNOW THAT I CAN ALWAYS BUY ANOTHER CD PLAYER AND FORGET ABOUT THIS PROBLEM. But I just want to figure this out. Any help will be most appreicated. Thanks in advance............. |
#2
Posted to rec.audio.tech
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QUESTION: Strange Yamaha CD Player Behaviour
"EADGBE" wrote in message ... I purchased a Yamaha CDX-710 CD player at a yard sale. It has new belts and plays and sounds great, BUT...sometimes a disc will skip badly. Since all of my discs are in mint condition, I knew it had to be the player. I opened the player up and discovered something. Take a look at this photo: http://i240.photobucket.com/albums/f...123/yamaha.jpg If I press down gently at the location indicated in the photo, the skipping stops immediately and the disc plays perfectly. I don't have to KEEP my finger there -- I simply have to press down on the part immediately above the center of the spinning disc, and everything sounds fine. HERE IS THE WEIRD PART: I have looked VERY CLOSELY at this spot, from all angles, when I press down. I CANNOT SEE OR FEEL ANY MOVEMENT. Nothing "clicks" into place or shifts into (or out of) position. I simply have to touch this spot and the disc no longer skips. Nothing at all seems to be mis-aligned or out of place. Sometimes the player plays discs perfectly, and I don't have to touch anything at all. But other times, when the disc player is skipping, all I have to do is touch the top of the disc clamp and everything is fine. WHAT IS GOING ON? What could possibly be out of place? If something IS out of place, it surely can't be by much. I can't stress enough that I cannot see or feel ANYTHING different when the disc is skipping OR when it has been corrected. I KNOW THAT I CAN ALWAYS BUY ANOTHER CD PLAYER AND FORGET ABOUT THIS PROBLEM. But I just want to figure this out. Any help will be most appreicated. Thanks in advance............. Hmmmm Two possibilities I can think of, but neither convinces me terribly:- 1) The spindle the CD sits on has some very small amount of dirt on it that stops the CD sitting flat. Pushing on the top pushes the CD down, but it's such a small distance that you can't feel it. If the disk isn't perfectly aligned, the servo that keeps the lens focused won't be able to keep up, and the disk won't play. I made the mistake of sticking paper labels on many of my early CD-Rs, and over a few years, the paper has shrunk, warped the disk by fractions of a mm, and the disk won't play any more. Removing the sticky labels lets the disk go flat and they play again. Could be something similar in your case that won't let the disk go flat down until you give it some help. 2) The clamp isn't holding properly, allowing the disk to slip on the spindle and the player loses lock and can't play the CD. Maybe again a small piece of dust that stops the clamp holding properly, and pushing down on the clamp gives the magnetic centre a bit of help. I don't know if you've cleaned everything around where the disk sits, but that's what I would look at first. Good luck, these intermittent faults are the very devil to find. S. -- http://audiopages.googlepages.com |
#3
Posted to rec.audio.tech
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QUESTION: Strange Yamaha CD Player Behaviour
"EADGBE" wrote in message ... I purchased a Yamaha CDX-710 CD player at a yard sale. It has new belts and plays and sounds great, BUT...sometimes a disc will skip badly. Since all of my discs are in mint condition, I knew it had to be the player. I opened the player up and discovered something. Take a look at this photo: http://i240.photobucket.com/albums/f...123/yamaha.jpg If I press down gently at the location indicated in the photo, the skipping stops immediately and the disc plays perfectly. I don't have to KEEP my finger there -- I simply have to press down on the part immediately above the center of the spinning disc, and everything sounds fine. HERE IS THE WEIRD PART: I have looked VERY CLOSELY at this spot, from all angles, when I press down. I CANNOT SEE OR FEEL ANY MOVEMENT. Nothing "clicks" into place or shifts into (or out of) position. I simply have to touch this spot and the disc no longer skips. Nothing at all seems to be mis-aligned or out of place. Sometimes the player plays discs perfectly, and I don't have to touch anything at all. But other times, when the disc player is skipping, all I have to do is touch the top of the disc clamp and everything is fine. WHAT IS GOING ON? What could possibly be out of place? If something IS out of place, it surely can't be by much. I can't stress enough that I cannot see or feel ANYTHING different when the disc is skipping OR when it has been corrected. I KNOW THAT I CAN ALWAYS BUY ANOTHER CD PLAYER AND FORGET ABOUT THIS PROBLEM. But I just want to figure this out. Any help will be most appreicated. Thanks in advance............. These are common problems on the old Yamaha's. 1. The clamper you show in the picture need to be taken apart and the old lubricant replaced. When you take it apart, you will see the gummy old lubricant on the ball bearing. 2. The spindle motor needs a bit of oil at the shaft where it goes into the top of the motor. Use a light oil, and use a cotton swab or tissue to remove any excess oil. Make sure there is no hair etc at the motor shaft. End of problem. Mark Z. |
#4
Posted to rec.audio.tech
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QUESTION: Strange Yamaha CD Player Behaviour
A fair number of years ago, I was working in factory service, and
serviced many CD players. I was doing the laser and servo tracking alignments on the bench. I serviced hundreds of units. I have not serviced your model. The suggestion to take apart the clamper and service it is an excellent solution. The mechanical parts should be cleaned and properly lubricated. Another thing that can be a problem with some of these players is that the laser focus and servo adjustments may have to be done. This is not something you an do by ear or by eye. It is done using the service manual, and using a scope, DVM, and calibration CD. Once you are sure that the mechanics of the player are in proper spec, and if you know where the laser focus adjustment is, you can try winging or shot-gunning it. Mark exactly where the pot is so you know the start point, and try tweaking it in one direction a little at a time. If it is getting worse, go the other way. You may reach a point where it will work properly for you. If you find that the best spot is not working properly and there is no performance difference, locate the laser intensity adjustment. Try winging that one a little. This is usually a very touchy adjustment. You can try it in one direction using small increments. Because you were able to get the player to work by pressing down on the top of the spindle assembly, I am assuming more in the favour of a laser focus problem. Where you will not be able to do any adjustments is if the player is using computer interfacing for the alignments. This is where a computer interface is connected to a port on the main board or a daughter board of the player, and a software is used to do the set-ups. There will be no alternative but having factory service. At this point, it would be cheaper to buy a new player. -- JANA _____ "Mark D. Zacharias" wrote in message news "EADGBE" wrote in message ... I purchased a Yamaha CDX-710 CD player at a yard sale. It has new belts and plays and sounds great, BUT...sometimes a disc will skip badly. Since all of my discs are in mint condition, I knew it had to be the player. I opened the player up and discovered something. Take a look at this photo: http://i240.photobucket.com/albums/f...123/yamaha.jpg If I press down gently at the location indicated in the photo, the skipping stops immediately and the disc plays perfectly. I don't have to KEEP my finger there -- I simply have to press down on the part immediately above the center of the spinning disc, and everything sounds fine. HERE IS THE WEIRD PART: I have looked VERY CLOSELY at this spot, from all angles, when I press down. I CANNOT SEE OR FEEL ANY MOVEMENT. Nothing "clicks" into place or shifts into (or out of) position. I simply have to touch this spot and the disc no longer skips. Nothing at all seems to be mis-aligned or out of place. Sometimes the player plays discs perfectly, and I don't have to touch anything at all. But other times, when the disc player is skipping, all I have to do is touch the top of the disc clamp and everything is fine. WHAT IS GOING ON? What could possibly be out of place? If something IS out of place, it surely can't be by much. I can't stress enough that I cannot see or feel ANYTHING different when the disc is skipping OR when it has been corrected. I KNOW THAT I CAN ALWAYS BUY ANOTHER CD PLAYER AND FORGET ABOUT THIS PROBLEM. But I just want to figure this out. Any help will be most appreicated. Thanks in advance............. These are common problems on the old Yamaha's. 1. The clamper you show in the picture need to be taken apart and the old lubricant replaced. When you take it apart, you will see the gummy old lubricant on the ball bearing. 2. The spindle motor needs a bit of oil at the shaft where it goes into the top of the motor. Use a light oil, and use a cotton swab or tissue to remove any excess oil. Make sure there is no hair etc at the motor shaft. End of problem. Mark Z. |
#5
Posted to rec.audio.tech
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QUESTION: Strange Yamaha CD Player Behaviour
THANKS to everyone very much for all of the great information so far!
I have some time off coming and will try a couple of the suggestions. I will be sure to let you all know how it turns out. Thanks again! :-) |
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