Not Recognising a CD

Hi,
Although there are many things that could cause this problem, there are three that are the most common. They are... Bad laser, dirty laser lense, or bad spin motor. You have already removed the top cover, but be careful never to power up the unit with the laser lense exposed, or you will be performing home laser eye surgery on yourself with very bad results!
When you close the CD drawer, listen carefully to make sure the loading motor stops...if the belt is slipping, the mech never gets the "drawer closed" signal, and the disk will not spin. If the drawer is closing ok, listen for a faint "ticking" sound, this is the laser lense going up & down trying to focus on the disk. If you hear that sound, but the disk doesn't spin, try gently spinning the disk clockwise with your finger.. if it starts to spin & finds the directory, then the spin motor has developed a dead spot, and the unit may work fine several times until it lands in that same spot again. If that is the case, the spin motor must be replaced. To clean the laser lense, you will need some rubbing achohol & cotton swabs. Make sure it is at least 70% USP not the dollar store suff, (50% water). I'm not familiar with your model, but likely you will have to remove a cover that holds the clamping ass'y that is usually a round piece with a magnet inside that clamps the disk to the spin motor. Saturate the swab with alchohol, and touch the lense..the alchohol should cover the lense forming one big drop, then VERY gently move the drop around with the same end of the swab to loosen any debris. Then take a dry swab or the dry end if double ended swab, and touch it to the lense. The alchohol, (and hopefully the dirt),should instantly sponge up into the dry swab, then assemble and try unit. If all this fails, the laser has likely failed, and must be replaced & aligned by a competant repair shop.

I hope this helps!
Good Luck!

I got a second hand 541 a few weeks ago. After many hours of listening pleasure an no problems at all, the machine stopped spinning CD's, both copied ones and original ones.

The sollution for my problem was simple after some figuring out.

Open the CD tray.
Power off the unit with the tray open.
Open it up.
In the CD frame in the back there are 2 srews that hold the CD engine unit in place. I untidied these screws just a little bit.
I also untidied the screws that hold the cd clamp cover on the top a little.

After this it loads all my CD's fine again.

NAD CD platters tend to go dry on the guides, stopping the bottom CD clamp from fully engaging. Disconnect the signal and power leads and undo the four screws connecting the transport to the bottom of the case. Remove and get some very fine grease and smear it lightly on all the runners and guides. Also look at the crank which causes the bottom clamp to move up and down, turn the flywheel by hand and watch it move, see where the plastic lug moves to cause the bottom clamp to move. Grease that too. Wipe any spare grease off so only the minimum is used. Do not use oil. Dean Beedell