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CD songs distorted badly first two or three songs.

earlybird

Oct 26, 2020
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I have a Sony CFD-758 CD Cassette Radio. When I play a CD, the first two or three songs are distorted badly. After that they seem to play smooth. I have used two different standard CD cleaners. One uses a drop of fluid on the felt. The other uses no fluid. I have applied these cleaners more times than I care to count. No help. They still skip and miss the first two or three songs. I can not see the laser head or I would clean it physically. How can I solve this problem? Old but great stereo system. Hate to give this machine up. Thank you in advance for any help you can give me.
 

kpatz

Feb 24, 2014
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Sometimes those older Sony boombox CD players develop oxidation on the connections between the main board and the laser pickup. Try opening it up and disconnecting and reconnecting the ribbon cables and see if that helps.

Since it's occurring more on the first few tracks, it could also have a tracking issue as well when the CD is spinning faster.
 

shrtrnd

Jan 15, 2010
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They DO sell discs with brushes on them to clean the laser lens, but your symptom makes me wonder if maybe there's a problem with the motor taking a while to get up to speed?
 

bertus

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Nov 8, 2019
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Hello,

A CD is read from the inside to the outside.
The CD is spinning faster at the beginning of the CD.
Is there moisture near the center of the spindle?

Bertus
 

Alec_t

Jul 7, 2015
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CDs can also suffer from age-related data loss, which can cause track skipping.
 

earlybird

Oct 26, 2020
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[mod edit: deleted double quote and partial reply]
If you put it on "shuffle" is it the same tracks that play badly?

I did the shuffle test and the same tracks skip. Other reply's have indicated that it might be oxidation. I do not think that is the problem. It would seem that if that was the problem, there would be a problem with all the tracks. I have used a CD cleaner with brushes and also without brushes. Not sure about moisture. The unit has been in the house and there is air and heat. It is not the data on the CD as this happens to all Cd's
I know very little on how to repair these units. But I did notice on one of my CD players where I can see the laser lens. it appears that the lens moves. If that is the case, it would seem like the movement is being hampered at the beginning first two or three tracks. Not sure how to get into this unit. Do the speakers come off the side? It would be nice to see what the inside looks like. Again, I have never opened one of these up. Be a Ham Radio Operator for 40 years and have opened radios. Never a CD unit. So I am flying blind here.
I apologize if this reply is in the wrong position here. First time on this. I have tried to answer all replies that I have received so far. Thanks again if you can help me with this unit. It is in mint condition otherwise and the sound its terrific.
 
Last edited by a moderator:

PETERDECO

Dec 19, 2019
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Open the unit up, locate the laser lens and clean it with a cotton swab wetted with contact cleaner. You can use rubbing alcohol but if you do, wait a while before playing a CD as rubbing alcohol has water content.
 

Alec_t

Jul 7, 2015
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If the problem occurs with all CDs then I'd suspect the culprit is the mechanism which moves the read-head radially. Could be tacky/hardened lubricant causing excessive friction.
 

earlybird

Oct 26, 2020
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I am going to take this critter apart. I believe that Alec_t has the solution. It has friction in moving the lens at tracks one and two and less at track three. At age 79, I have taken a lot of things apart. A CD player will now be added to my list. If anyone knows anything about taking this particular unit apart, please let me know. I am flying blind on this one. It is a Sony CFD-758 CD Cassette Radio. Thanks again for any help you can give. It is deeply appreciated.
 

earlybird

Oct 26, 2020
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Thanks for the Service Manual information. Here is what I am doing. Going with the thought that Alec_t had that the lubricant has hardened and is causing friction at track 1,2,and 3, I put in a CD and am playing those three tracks over, and over, and over in hopes that I can loosen the lubricant up. Oddly enough, it appears to be working. It is playing better and better all the time. Time will tell if this may solve the problem without opening the unit up. This idea that Alec_t mentioned reminds me of the same problem that I had with a power window in a car. Come to find out it would not work properly because the lubricant hardened on the up and down unit. Again, time will tell. Nothing lost trying this approach. Thanks again all for all your help.
 

kpatz

Feb 24, 2014
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There's more than one way the laser lens moves.

First of all, the lens itself can move up and down (to focus the beam), and laterally (in and out) to track the data spiral on the disc. This is done using a mechanism that lets the lens "float" and be moved precisely and quickly using electromagnets. This mechanism keeps the lens focused on the disc as it spins, and it follows the data spiral as the disc plays, but the range of this mechanism is only enough to play a few seconds of a track before it reaches its limit, so then the other mechanism comes into play, which moves the entire laser assembly in and out, usually a gear driven motor/servo with the entire assembly on rails. This is the noise you hear when you jump from track to track, or when the disc finishes playing, you hear a motor for a few seconds (returning the assembly to its start position at the beginning of the disc).

The former "floating lens" mechanism rarely has friction issues, and if it did, it would probably have trouble playing the entire disc, not just the first few tracks, though the disc does spin faster at the beginning of the disc so the tracking servos do have to work harder. The mechanism that moves the entire assembly in and out is more likely to have binding issues if the lubricant has dried out, which could be causing your issues. While playing a disc, this mechanism has to move in small, precise increments in conjunction with the lens tracking to allow the assembly to stay on track... if you open up a CD player and watch it play a disc, you can see the motor turn periodically as the lens tracks from the inside of the disc outward. When jumping from track to track, this motor runs at a higher speed and probably overcomes the friction better, but if it's sticking, it could have issues with the small incremental turns.

If you can get to the innards, I'd try cleaning the rails with a swab, and verify the assembly is moving freely along its full travel. Some light lubricant might help, but use just a tiny amount and be careful not to get it on the laser assembly or lens, or anything that might come in contact with the CD.

If playing the 1st 3 tracks over and over is helping, another thing to try is to put on the longest CD you have (80 minutes or so), and play the last track to the end, then let the player stop, to make the assembly move over its entire range of travel. Do this repeatedly to spread the lubricant over the rails. Another option is to program the player to play the first and last tracks of an 80 minute CD, then let it run on repeat for a few hours.
 

earlybird

Oct 26, 2020
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Today I played the first three tracks over and over. It seems to have improved greatly but still ships. I did look at another unit I have and can see the lens. It does move from inside to outside and it does float. I see what you mean. It does travel on tracks and they seem to be spiral tracks. I have down loaded the service manual also. Sure want to get this thing up and running.. I will work on your thought of putting a long CD on hoping to loosen up the lub. But I think the best thing to do is to get in there and do what needs to be done. Sorry if this is posted in the wrong place. I am having a problem how to reply or just add on to the thread.

[Mod edit: removed double quotation]
There's more than one way the laser lens moves.

First of all, the lens itself can move up and down (to focus the beam), and laterally (in and out) to track the data spiral on the disc. This is done using a mechanism that lets the lens "float" and be moved precisely and quickly using electromagnets. This mechanism keeps the lens focused on the disc as it spins, and it follows the data spiral as the disc plays, but the range of this mechanism is only enough to play a few seconds of a track before it reaches its limit, so then the other mechanism comes into play, which moves the entire laser assembly in and out, usually a gear driven motor/servo with the entire assembly on rails. This is the noise you hear when you jump from track to track, or when the disc finishes playing, you hear a motor for a few seconds (returning the assembly to its start position at the beginning of the disc).

The former "floating lens" mechanism rarely has friction issues, and if it did, it would probably have trouble playing the entire disc, not just the first few tracks, though the disc does spin faster at the beginning of the disc so the tracking servos do have to work harder. The mechanism that moves the entire assembly in and out is more likely to have binding issues if the lubricant has dried out, which could be causing your issues. While playing a disc, this mechanism has to move in small, precise increments in conjunction with the lens tracking to allow the assembly to stay on track... if you open up a CD player and watch it play a disc, you can see the motor turn periodically as the lens tracks from the inside of the disc outward. When jumping from track to track, this motor runs at a higher speed and probably overcomes the friction better, but if it's sticking, it could have issues with the small incremental turns.

If you can get to the innards, I'd try cleaning the rails with a swab, and verify the assembly is moving freely along its full travel. Some light lubricant might help, but use just a tiny amount and be careful not to get it on the laser assembly or lens, or anything that might come in contact with the CD.

If playing the 1st 3 tracks over and over is helping, another thing to try is to put on the longest CD you have (80 minutes or so), and play the last track to the end, then let the player stop, to make the assembly move over its entire range of travel. Do this repeatedly to spread the lubricant over the rails. Another option is to program the player to play the first and last tracks of an 80 minute CD, then let it run on repeat for a few hours.
 
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earlybird

Oct 26, 2020
6
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I am just not sure to start my comments with "Reply to thread" or "reply' to individual posts and getting things winding up in the wrong place. I am just new to this Forum. I have been on forums in regard to flying remote control airplanes and also Ham Radio and have no problem since I use then often. The problem here is not you but me. I will get it.

In regard to my CD skipping at tracks one, two and three, there seems to be some hope. Yesterday after playing those three tracks over and over, the problem got much, much better. This morning I got up and played those three tracks again and the first time there were only about two or three places it skipped. The second time I did it, it played perfectly through all three tracks.. Same results with the third time.

So I am going to use the advice of kpatz and put a CD in, program it for track #1 and the last track, set it on repeat, turn the volume down and run it for several hours and see if this sliding back and forth on the track will break up any tight lub that might be there. Hopefully I can bring this back to life. This unit was bought somewhere around 1992 I think. It was treated with love and kindness. No abuse on this unit. Just as a point of possible adding some information, let me say this. The unit was sitting on a TV stand and just below it was an air and heat vent. It was in a corner and it is possible that it got more heat or air there that might have a bearing on why the lubrication hardened. Just a thought. When I started have trouble with this unit, I bought another Sony, HCD GX355 Compact Disk Deck Receiver and this unit I am having a problem with kind of went to the back burner and has not been used for years. That in itself could have caused the lubrication to get even harder. But having pulled this problem unit out of moth ball, I just might get it up and going again. A note on that new unit I bought, the HCD GX355 Compact Disk Deck Receiver. That thing is dynamite. Excellent.in every way. Just in case anyone wants to know. I love my music and this guy does not let me down. But then again, my CFD-758 is great also. Hopefully we can restore it and get it back in good health. Thanks one and all for all your tips and help. It is deeply appreciated. A day without music is like a day without sunshine. Not good. Not good at all.. . .
 

Harald Kapp

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I am just not sure to start my comments with "Reply to thread" or "reply' to individual posts
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