Nak CD Player 2 Bad Laser? Bad DAC? What?

[boreas]

I have a Nakamichi CD Player 2 (Actually I have two.) that's not working. Discs will load, the TIME DATA and tracks are displayed and when the PLAY button is pressed the the play indicator appears and the disc spins up but doesn't actually play (most times). On rare occasions play will begin but the audio is very distorted and the player usually stops within a few seconds, though once it played for about two minutes before stopping. No error message ever appears.

Any help will be appreciated. The player is cosmetically almost perfect so I'd like to get it working.

John

 

[AudioWizard]

By distorted, does it actually sound a scratchy ? Could be a spindle motor not getting up to speed, most of the CD players use a brushed motor, thus bad contacts on the brushes/ commutator. If a CD shows the time/track then the laser did read the TOC( table of contents). If the spindle motor won't maintain the correct speed then the data isn't coming off the disc at the correct rate thus distorted/scratchy sound. Also realize that after the TOC, which is located at the inner portion of the disc,that the CD must spin at its highest rpm so it is hard on the motor to get up to it's correct speed if it is defective.You might try some Deoxid on the motor brushes to verify( most spindle motors have small openings around the brush area) If it helps then replace the spindle motor, the deoxid is a bandaid in this case or a tail lite warranty.

 

[boreas]

By distorted, does it actually sound a scratchy ? Could be a spindle motor not getting up to speed, most of the CD players use a brushed motor, thus bad contacts on the brushes/ commutator. If a CD shows the time/track then the laser did read the TOC ( table of contents). If the spindle motor won't maintain the correct speed then the data isn't coming off the disc at the correct rate thus distorted/scratchy sound.

Yes, constantly scratchy.

Also realize that after the TOC, which is located at the inner portion of the disc,that the CD must spin at its highest rpm so it is hard on the motor to get up to it's correct speed if it is defective.You might try some Deoxid on the motor brushes to verify( most spindle motors have small openings around the brush area) If it helps then replace the spindle motor, the deoxid is a bandaid in this case or a tail lite warranty.

Thanks! Very helpful indeed. That sounds like it may be the problem. Now I'll have to dig into the thing to see how deeply buried the spindle motor is. And then figure out where to find a motor for a 30 year old player.

John

 

[FileFixer]

If you need new laser on Nak CD 2, pickup is KSS-150A /KSS-210A. DAC chip is 2 x PCM1700P and Oversampling filter is SM5840CP. All chips are cheap and available, about $20/pcs, as laser pickup too. All chips are on DIP package.

 

[onanysunday]

Try a drop of light machine oil onto the spindle motor shaft. Make sure laser lens is clean and nothing is stuck behind it. If you gently push it down with a Q-tip it should bounce back. Make sure the laser assembly moves freely down the track and the track is cleaned off with no ridges of old, dried out grease on the ends of travel. Apply the lightest coat of white lithium grease to lube moving tray components.

Hopefully the pots haven't been fiddled with or calibration would be difficult without specialized equipment. The "distortion" would be the hardest part to remedy. You should be able to mark the original settings for the pots TG tracking gain and FG focus gain. You do this so you can revert back to the original settings. Ideally you would use a razor blade to make a thin razor mark but this can be hard to see. A brightly colored fine tip marker works well. The pots may not be labeled tg or fg and you may have to figure out which pots corresond to these parameters. Turn them clockwise very slowly a micro amount each time. Listen for gradual improvement, slowly, over time. Less is more. You should be able to get the disc to play more consistently (if the laser is capable of it) from here you would just have to figure out the distortion piece.

I've cleaned up the signal in a lot of old CD players by completely recapping them but it is hard to recommend doing this as a guaranteed solution to your problem. Good luck. I have a Nak CDC-4A, really an exceptional sounding player and one of my best.

 

[Mr. Nick]

On rare occasions play will begin but the audio is very distorted and the player usually stops within a few seconds, though once it played for about two minutes before stopping.

I've cleaned up the signal in a lot of old CD players by completely recapping them but it is hard to recommend doing this as a guaranteed solution to your problem.

Vote this for solution.
Power supply capacitors are probably wasted.
I just fixed Denon DCD 1560 by replacing the capacitors with similar symptoms.

What kind of "light machine oil" is the oil you guys recommend?
There are probably 1001 different oils for different purposes.

 

[onanysunday]

It's just called machine oil or also called sewing machine oil. Also good to have white lithium grease as well when working on CD players when lubricating parts other than motor spindle shafts.

Of course if you see any bulged capacitors that would be a dead giveaway as well but it's usually not so obvious when capacitors go bad as they slowly lose capacitance over time and ESR goes up as electrolyte dries out. I am not sure what capacitors are inside the Nakamichi but I'm sure they used high-quality Japanese capacitors to begin with, most likely United Chemi-Con, Nichicon, or Elna.

 

[Mr. Nick]

Alrighty. Machine oil it is then. I must get a can of that for shafts and tray system lubrication, before I put it back to service for good.

The capacitors (AVF series) in this Denon looked like brand new, but they must have been out of spec, even tho they measured fine with DMM out of circuit.
It's different when voltage is applied to the circuitry.