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Troubleshooting CD Players

@rockrink, maybe a long shot, but could need recapping in the motor drive and servo circuits. I've had some early Technics players from circa 1984-86, that had bad electrolytics that screwed up the spindle motor running smoothly (or at correct speed), thereby throwing off the ability to read a disc properly. Worth a look, since you've already installed a new laser and have what looks like a good eye pattern on the scope.
 
Peeps. I just bought a non working MCD500. The issue that previous owner mentioned is the disc spins with lot of noise and won’t play. Removed top cover and notice that maybe the laser mechanism is little high as I noticed when a disc is ejected it slightly touches the top plate. Now when loading a disc it needs some help to move and once it moves it goes on to read. TOC is displayed and disc stops. Hit play the disc spins and is stuck at 0.00. This seems to be a denon transport. I do notice that laser moves up and down and there is red laser light. Anything troubleshooting steps that is recommended
 
kiran1103 said:
Peeps. I just bought a non working MCD500. The issue that previous owner mentioned is the disc spins with lot of noise and won’t play. Removed top cover and notice that maybe the laser mechanism is little high as I noticed when a disc is ejected it slightly touches the top plate. Now when loading a disc it needs some help to move and once it moves it goes on to read. TOC is displayed and disc stops. Hit play the disc spins and is stuck at 0.00. This seems to be a denon transport. I do notice that laser moves up and down and there is red laser light. Anything troubleshooting steps that is recommended
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Almost sounds like the disc platform attached to the spindle motor is sitting too low. It's possible it may not be positioned correctly due to either downward pressure placed on it, or if the set screw attaching it to the spindle worked loose and allowed it to move out of position, causing physical interference/rubbing.
 
I took some pictures. Although the motor and lens are on same platform so don’t think the height to cd is effected. It does struggle to clamp. But once clamped it goes to read TOC but after this it doesn’t play. Stuck at 0:00. When I change the tracks the speed is changing depending on where the track is. Can’t see if the lens moved but am sure the lens is moving. First pic there is lot of grease. I added the white DOW grease and its still not smooth.




IMG_1964.jpegIMG_1965.jpegIMG_1967.jpegIMG_1966.jpeg
 
Perhaps an issue with the clamping mechanism then. I've had a couple of assorted
players here where the clamp came down too tightly, or was somehow out of adjustment. I'm not familiar with the mechanism in the MCD500, so am sort of grasping at straws for an explanation.

Some players also have a "suspension" for the lower portion of the tray mech and optical block that sags with age. If this happens, it exerts downward force on the disc spindle platform, and when the clamp is closed it pulls downward in it as well, increasing friction in the process.
 
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@kiran1103 , it appears the rubber portion of the spindle has lint on it. Foreign objects on the rubber can cause disc read errors, so it should be cleaned thoroughly. The rubber can also harden with age, causing slippage with the disc. I use a product called 408C Rubber Renue to treat and soften the rubber, which eliminates slippage.
 
@eiraved raises a good point. The anti-slip material on the spindle platform has to keep the disc firmly in place. Slippage can result if it's dirty or worn. I have had a couple of vintage players on which that was an issue, so it's absolutely worth checking.
 
kiran1103 said:
Peeps. I just bought a non working MCD500. The issue that previous owner mentioned is the disc spins with lot of noise and won’t play. Removed top cover and notice that maybe the laser mechanism is little high as I noticed when a disc is ejected it slightly touches the top plate. Now when loading a disc it needs some help to move and once it moves it goes on to read. TOC is displayed and disc stops. Hit play the disc spins and is stuck at 0.00. This seems to be a denon transport. I do notice that laser moves up and down and there is red laser light. Anything troubleshooting steps that is recommended
Click to expand...
If you haven't already, you should read this thread starting from page 1. Lots of good information here, and you may come across a solution to your particular problem.
 
Thank you. I didn’t feel any rubber part in that top part. I sprayed isopropyl and deoxit which may have worsened it. It feels like just metal to metal rubbing. I read somewhere that someone put felt pads. I don’t think mine is removable without making damage. If I damage it there is no replacement. Anyway once it spins it’s able to read TOC and then play does nothing. I will read through all the pages to get some more ideas. Thanks once again
 
kiran1103 said:
Thank you. I didn’t feel any rubber part in that top part. I sprayed isopropyl and deoxit which may have worsened it. It feels like just metal to metal rubbing. I read somewhere that someone put felt pads. I don’t think mine is removable without making damage. If I damage it there is no replacement. Anyway once it spins it’s able to read TOC and then play does nothing. I will read through all the pages to get some more ideas. Thanks once again
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The second and third picture show the black rubber spindle. That needs to be cleaned with soap and water, not isopropyl which will dry the rubber. Check that it is supple and has some "grab" to it.

spindle.jpeg
 
So today I replaced the laser mechanism and still same. It reads ToC and then when hit play it’s at 00:00 and nothing. The disc spins and when I move to tracks I can sense the lens moving positions. When at last track the speed also increases. It’s just that the counter stays at 00:00. The clamping is fine and no slips. One thing I am going to try is change the 24pin ribbon cable and see. Is it something with servo board or something else? I want to fix this. I do have an oscilloscope but am still learning. I don’t know where to probe snd what to expect. The laser I replaced is same part as old one. Bought it locally in NJ and appears to be original. It’s a Sanyo sf hd66. Any other steps to perform. Thanks
 
Don't know if I should start a new thread or just tag on here.... thanks in advance for the guidance.

I'm working on an Adcom GCD-575 (Sony laser/transport mechanisms). I've been through all the steps; it appears to do a focus search but the disc does not spin. There is a high-pitched squealing sound (maybe that's what is meant by a "sizzle"). It will not start spinning even with gentle assistance from my finger.

So this could indicate a bad spindle motor... BUT... if I take out the transport and remove the green PCB that attaches to the laser sled and spindle motors, and I apply 5V DC direct to the spindle motor, it'll spin the disk with absolutely no problem and no squeal. So does that eliminate the motor as being bad? If so, what would be the next thing to try?
 
Pioneer Elite PD65 CD Player Intermittent problems.

I have looked through the forum and cannot find anything like what I am experiencing but if there is a link would someone be kind enough to link me?

I am the original owner of this PD65, I have not played it in 19 years, it has been in it's original box.

A few weeks ago I started to setup an audio system and took the player out, plugged it in and all was normal. Then after a couple days I put a CD in and closed the drawer, the player made a high pitched squeal and the time indicator just showed 00:00. Hit eject and it would indicate it was opening but it would not. I have to power the player off and then turn it on and immediately hit the open button and the disc comes out spinning fast. I repeat this process a few times and then the player starts to work, cd goes in, shows time of cd and then goes to 00:00, I hit play and it plays. 3 times after playing a little while the music starts to do a digital distortion fade where you can still here the music but it is a little lower in volume and is very distorted. HOWEVER USUALLY once I go through the process initial powering off and on until the squeal stops the player works all day without any issues. They do not start up again until the next day when I turn the player on.

Any ideas or guidance? I would like to keep this player/get it repaired if possible.

Thank you all in advance. I can attach a video if that helps.
 
I have an Integra DPC-8.5 that will not play some CDs that play just fine in my computer's drive. The CDs that it won't play don't spin at all. From what I've been able to learn, the unit may benefit from a focus bias adjustment, although I'm not certain about this because I've also read that usually burned CDs are the first to give trouble, and it has played all burned CDs that I have tried. If I am on the right track with adjusting the focus bias, can anyone tell me which of the two trim pots on the bottom of the KHM-280AAA laser assembly I should be adjusting? If I am not on the right track, what other causes should I be investigating?

Thanks much!
 
One topic that has received some limited commentary relates to the height of the hub on which the CD ultimately rides.

What is the more important measurement?
- An absolute installed height as measured from the top of the hub to the 'base' where the spindle exits ? or
- a relative installed height measured from the top of the laser assembly to the bottom of the hub? (Sort of like gapping a spark plug.)

I have a CD player where the hub is not terribly secure and collides with the laser assembly in its initialization to find the home position.

It strikes me that the relative position is the key measurement, but I have nothing but instinct to base this upon.

Thanks for the input!
 
JSMATT said:
One topic that has received some limited commentary relates to the height of the hub on which the CD ultimately rides.

What is the more important measurement?
- An absolute installed height as measured from the top of the hub to the 'base' where the spindle exits ? or
- a relative installed height measured from the top of the laser assembly to the bottom of the hub? (Sort of like gapping a spark plug.)

I have a CD player where the hub is not terribly secure and collides with the laser assembly in its initialization to find the home position.

It strikes me that the relative position is the key measurement, but I have nothing but instinct to base this upon.

Thanks for the input!
Click to expand...
What type of CD player do you have where the collision with the laser assy occurs?
 
JSMATT said:
One topic that has received some limited commentary relates to the height of the hub on which the CD ultimately rides.

What is the more important measurement?
- An absolute installed height as measured from the top of the hub to the 'base' where the spindle exits ? or
- a relative installed height measured from the top of the laser assembly to the bottom of the hub? (Sort of like gapping a spark plug.)

I have a CD player where the hub is not terribly secure and collides with the laser assembly in its initialization to find the home position.

It strikes me that the relative position is the key measurement, but I have nothing but instinct to base this upon.

Thanks for the input!
Click to expand...
The CD player is a Denon with a KSS 240A.

Given that the hub was movable (but not loose), I decided to simply move it incrementally on the spindle, to see where the player would read a 'long' CD.

With the hub just flush with the top of the spindle, the laser could read a 74 minute or so CD without issues.

Will update the mm from the top of the spindle to the top of the laser assembly. My estimate is that is about 1 mm or so.

If the information I saw on the 'net' is correct, the laser has a focal length of 3-3.5 mm. And, it looks like the laser itself moves no more than 1.5 mm in its housing.

Finding info on a laser's focal length does not seem as easy as finding a data, such as from a transistor's or resistor's datasheet. At any rate, my layperson math for focal length, and (i) laser 'platform' to hub-top distance and (ii) travel of the laser in the KSS 240A itself seem to make sense.
 
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