NAD 521i Troubleshooting

I've had a 521i for about 2.5 years, and it suddenly stopped recognizing CDs, both burned and normal. When I push the close button, it brings the CD in, then makes a whirring noise for about 3-4 seconds, then just continues to blink without making the noise. When I re-open it, the CD doesn't appear to have moved.

Would anyone know what this problem is caused by, or how to fix it? I used compressed air and a cleaning CD on it, and it worked again for a few days, then just went kaput again.

Any advice would be greatly appreciated.
Interesting...I've just developed the same symptoms on the SAME model cd player, bought Nov. 02.

Design fault, anyone?

Time for an email to NAD.
NAD says:

"There was never a known problem with the C521i at all, or a history of failure with this unit. We do not offer an extended warranty."

Off to the repair center, I guess.
another interesting comment.same problem with SAME model with SAME attempt at cleaning with compressed air [probably the same air brand ie "DUST OFF" ] and a cleaning disc with same temporary results. NAD doesnt seem to care much!!
Mine has the same problem. The reason seems to be simple:
It is a belt that drives the movement of the cd tray and the elevation of the cd drive to pick up the cd and spin it. The belt is not producing enough friction ...... And that is why the cd deice does not the correct position preventing it from spinning the CD. Easy fix: replace the belt. You have to open the player and get the tray as far out as possible to see the belt. Just turn it around and it will work again.
.......another solution if the rubberbelt needs to be replaced: get any old CDROM drive out of a junkyard computer, open it up and look for the motor and the belt that drives the cd tray - there is usually only one. Get it out and transplant it to the 521i. The steps are: get the cd tray into open position, unplug the player, open the housing (5 screws), push two small lids close to front panel left and right to the cd tray and you can pull the tray out a little bit further, use a screwdriver to press down the cover over the belt-drive, lift it a little bit, remove the old belt and put the new one in, push the cover back into place, push the cd tray back into position and close the housing again.......done. Works great with mine and is done in less than 30 min!
This may help

reconditioning the belt

I think the replacement belt is
sony replacement belt
SONY 3-653-387-00 BELT ( 365338700 ) OEM ORIGINAL PART