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3. Blow carefully into the ball cage to dislodge dust and lint.
4. If the rollers inside the ball cage are dirty, clean the rollers with a cotton swab moistened lightly with isopropyl
alcohol.
5. Recenter the rollers in their channels if they are misaligned. Ensure that fluff from the swab is not left on the
rollers.
6. Replace the ball and retainer ring, and turn the retainer ring clockwise until it clicks into place.
Floppy Drive
Clean your floppy drive using a commercially available cleaning kit. These kits contain pretreated floppy disks to
remove contaminants that accumulate during normal operation.
CDs and DVDs
If you notice problems, such as skipping, with the playback quality of your discs, try cleaning the discs.
1. Hold the disc by its outer edge. You can also touch the inside edge of the center hole.
2. With a soft, lint-free cloth, gently wipe the bottom of the disc (the unlabeled side) in a straight line from the
center to the outer edge of the disc.
For stubborn dirt, try using water or a diluted solution of water and mild soap. You can also purchase commercial
products that clean discs and provide some protection from dust, fingerprints, and scratches. Cleaning products
for CDs are safe to use on DVDs.
FCC Notices (U.S. Only)
Most Dell computer systems are classified by the Federal Communications Commission (FCC) as Class B digital devices.
To determine which classification applies to your computer system, examine all FCC registration labels located on the
bottom, side, or back panel of your computer, on card-mounting brackets, and on the cards themselves. If any one of
the labels carries a Class A rating, your entire system is considered to be a Class A digital device. If all labels carry an
FCC Class B rating as distinguished by either an FCC ID number or the FCC logo, ( ), your system is considered to
be a Class B digital device.
Once you have determined your system's FCC classification, read the appropriate FCC notice. Note that FCC regulations
provide that changes or modifications not expressly approved by Dell could void your authority to operate this
equipment.
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received, including interference that may cause undesired operation.
Class A
This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of
the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the manufacturer's instruction manual, may cause harmful
interference with radio communications. Operation of this equipment in a residential area is likely to cause harmful
interference, in which case you will be required to correct the interference at your own expense.
Class B
This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of
the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential
installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the manufacturer's instruction manual, may cause interference with radio communications. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment off and on, you are
encouraged to try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and the receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/television technician for help.
NOTICE: Do not attempt to clean drive heads with a swab. The heads may become misaligned and prevent the
drive from operating.
NOTICE: Always use compressed air to clean the lens in the optical drive, and follow the instructions that come
with the compressed air. Never touch the lens in the drive.
NOTICE: To prevent damaging the surface, do not wipe in a circular motion around the disc.
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Documentation
6.07.2007
http://support.euro.dell.com/support/edocs/systems/720H2C/en/OM/appendix.htm