3.Repeat Steps 2 to select the track numbers you would like to delete, up to a maximum of 25 entries but cannot delete track above track 25.
4.To play the remaining tracks, just press PLAY. During playing, the SKIP buttons will access only the tracks still listed. The deleted songs are not listed.
5.To clear the memory, press STOP, OPEN/CLOSE to open the drawer, or switch off the power.
The Calender display will indicate remaining track listing. After completing playback, the C521i will automatically stop, and the display will again shown all the tracks contained on the inserted CD.
NOTE: In the Program-entry mode, the SKIP 
and 
buttons have a “wrap-around” function: if you SKIP Back repeatedly from Track 01, the number counts down from the final track on the disc. This provides a convenient way to select high- numbered tracks.
INSTALLING AND REPLACING BATTERIES
The remote control requires two 1.5-volt AAA-size (i.e. UM-4 or IEC RO3) cells. Alkaline cells are recommended, to obtain maximum operating life. To open the battery compartment, place your fingertip in the recess on the rear of the remote control, push against the flexible edge of the battery cover and lift the cover upwards. Install fresh cells, orienting them as shown on the diagram within the compartment.
The coil springs should contact the (-) end of each cell. Push the battery compartment cover back and press gently until it latches. In some cases, corrosion or fingerprint oil on the battery contacts may cause poor operation. Remove both cells, rub the metal contacts at both ends of each cell with a clean cloth or a pencil eraser, and re-install the cells, being careful to orient them correctly.
CD-R & CD-RW AUDIO DISCS
The C521i can play back CD-R & CD-RW audio discs that have been recorded on a computer or CD-recorder. The quality of CD-R audio discs varies widely which may affect playability.
Some factors that affect playability:
•The quality of the disc itself. Generally speaking, CD-R & CD-RW blanks from well-renowned companies give better results than unbranded ones.
•The quality of CD-recorder or computer CD re/writer. Some recorders and writers produce better results than others.
•The CD-R & CD-RW was created with high-speed writing. In general, the quality of a CD-R & CD-RW is better when produced at a lower speed against a higher speed on the same recorder or re/writer.
MAINTENANCE
At periodic intervals, open the disc drawer and wipe with a damp cloth to remove any loose dust.
HANDLING COMPACT DISCS
Handle Compact Discs with care. The playback of a disc will not be impaired by small dust particles, a few light fingerprints, or slight scratches. But large scratches, or a thick layer of oily fingerprints, can pre-vent the player from tracking the disc. (Incidentally, although the tracking optical pickup “plays” the disc through its clear side, the actual data surface is embedded directly beneath the label, protected only by a very thin coating of
lacquer. So a scratch that cuts through the label may damage the disc more than a similar scratch on the transparent “playing” surface. Thus you should treat both surfaces of the disc with care.) Severe scratches or fingerprints may cause the player to mis-track (skipping ahead, or repeating the same passage). Less severe damage may produce very brief bursts of high-frequency noise. The tracking and error-correction circuits of this NAD CD player are unusually sophisticated, providing secure tracking of flawed discs that are unplayable on some other players. Nevertheless, the discs should not be abused or handled carelessly. For best results, grasp the disc only by its edges.
CLEANING DISCS
Soiled discs may be cleaned by wiping with a soft cloth, either dry or moistened, with water. Do NOT use conventional LP record- cleaning products (cleaning solutions, sprays, treated cloths, or anti-static preparations), nor any kind of chemical solvent (alcohol, benzene, et al). A severely soiled disc may be washed in a warm-water spray, possibly with a small amount of a mild kitchen detergent added, and then wiped dry with a clean, soft towel.
When cleaning the disc, use only RADIAL strokes (from centre to edge). Never use a circular wiping motion like that used for cleaning ordinary LP records, because in wiping the disc there is a risk of scratching it. A radial scratch will do the least harm because it affects only a small portion of each circular data track, which can be fully compensated by the player’ s error-correction circuits. But a circular scratch that follows a data track may damage such a long continuous segment of data that it cannot be corrected.
ABOUT THE OPTICAL PICKUP
The Compact Disc player uses a solid-state semi-conductor diode laser, mounted on a tracking servo-mechanism, to play the disc. The laser illuminates the track of microscopic pits representing the digital data bits, while photo-diodes detect the reflected illumination from the disc and convert it into an electronic signal which is then decoded to recover the musical waveform in each stereo channel.
You cannot see the laser operating, because it operates at wavelength of 7800 Angstroms, which is in the infrared and thus invisible to the human eye.
The Compact Disc player is completely safe for children to use. The laser operates at very low power and is concealed within the player mechanism. Even when the player is disassembled, the laser remains sealed within an optical system that causes its light to focus only 1 millimeter from the lens and then diverge rapidly, reducing its intensity to negligible levels.
