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Presario 1200XL Series
Model XL300, XL300A, and XL300B
Removal Sequence
This chapter provides details for removing and replacing each component of the Presario
1200XL units.
Electrostatic Discharge
When removing or replacing parts, be careful to discharge static electricity before touching
the internal Notebook components. A sudden discharge of static electricity from a finger or
other conductor can destroy static-sensitive devices and microcircuitry. Often the spark is
neither felt nor heard, but damage occurs. An electronic device exposed to an electrostatic
discharge may not seem to be affected and continue to work perfectly throughout a normal
cycle. However, the discharge degrades internal layers, which reduces the operating life of
the device. Networks built into many integrated circuits provide some protection; but in
many cases, the discharge contains enough power to alter device parameters or melt
silicon junctions.
The table below shows the amount of static electricity generated by common activities
associated with servicing computers.
Electrostatic Voltage
Relative Humidity
Event
10% 40% 50%
Walking across carpet 35,000 V 15,000 V 7,500 V
Walking across vinyl floor 12,000 V 5,000 V 3,000 V
Motion of bench worker 6,000 V 800 V 400 V
Removing DIPS from plastic tubes 2,000 V 700 V 400 V
Removing DIPS from vinyl trays 11,500 V 4,000 V 2,000 V
Removing DIPS from styrofoam 14,500 V 5,000 V 3,500 V
Removing bubble pack from PCBs 26,000 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V