HP Pavilion Tx2500 Entertainment Notebook Pc Series Service Guide

							Grounding guidelines
Electrostatic discharge damage
Electronic components are sensitive to electrostatic discharge (ESD). Circuitry design and structure
determine the degree of sensitivity. Networks built into many integrated circuits provide some
protection, but in many cases, ESD contains enough power to alter device parameters or melt
silicon junctions.
A discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or
microcircuitry. Even if the spark is neither felt nor heard, damage may have occurred.
An electronic device exposed to ESD may not be affected at all and can work perfectly throughout a
normal cycle. Or the device may function normally for a while, then degrade in the internal layers,
reducing its life expectancy.
CAUTION:To prevent damage to the computer when you are removing or installing internal
components, observe these precautions:
Keep components in their electrostatic-safe containers until you are ready to install them.
Use nonmagnetic tools.
Before touching an electronic component, discharge static electricity by using the guidelines
described in this section.
Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible.
If you remove a component, place it in an electrostatic-safe container.
The following table shows how humidity affects the electrostatic voltage levels generated by different
activities.
CAUTION:A product can be degraded by as little as 700 V.
Typical electrostatic voltage levels
 Relative humidity
Event 10% 40% 55%
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
Motions of bench worker 6,000 v 800 V 400 V
Removing DIPS from plastic tube 2,000 V 700 V 400 V
Removing DIPS from vinyl tray 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 PCB 26,500 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V
Preliminary replacement requirements 33 
						

							Packaging and transporting guidelines
Follow these grounding guidelines when packaging and transporting equipment:
●To avoid hand contact, transport products in static-safe tubes, bags, or boxes.
●Protect ESD-sensitive parts and assemblies with conductive or approved containers or
packaging.
●Keep ESD-sensitive parts in their containers until the parts arrive at static-free workstations.
●Place items on a grounded surface before removing items from their containers.
●Always be properly grounded when touching a component or assembly.
●Store reusable ESD-sensitive parts from assemblies in protective packaging or nonconductive
foam.
●Use transporters and conveyors made of antistatic belts and roller bushings. Be sure that
mechanized equipment used for moving materials is wired to ground and that proper materials
are selected to avoid static charging. When grounding is not possible, use an ionizer to dissipate
electric charges.
Workstation guidelines
Follow these grounding workstation guidelines:
●Cover the workstation with approved static-shielding material.
●Use a wrist strap connected to a properly grounded work surface and use properly grounded
tools and equipment.
●Use conductive field service tools, such as cutters, screwdrivers, and vacuums.
●When fixtures must directly contact dissipative surfaces, use fixtures made only of static-safe
materials.
●Keep the work area free of nonconductive materials, such as ordinary plastic assembly aids and
Styrofoam.
●Handle ESD-sensitive components, parts, and assemblies by the case or PCM laminate. Handle
these items only at static-free workstations.
●Avoid contact with pins, leads, or circuitry.
●Turn off power and input signals before inserting or removing connectors or test equipment.
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							Equipment guidelines
Grounding equipment must include either a wrist strap or a foot strap at a grounded workstation.
●When seated, wear a wrist strap connected to a grounded system. Wrist straps are flexible
straps with a minimum of one megohm ±10% resistance in the ground cords. To provide proper
ground, wear a strap snugly against the skin at all times. On grounded mats with banana-plug
connectors, use alligator clips to connect a wrist strap.
●When standing, use foot straps and a grounded floor mat. Foot straps (heel, toe, or boot straps)
can be used at standing workstations and are compatible with most types of shoes or boots. On
conductive floors or dissipative floor mats, use foot straps on both feet with a minimum of one
megohm resistance between the operator and ground. To be effective, the conductive strips
must be worn in contact with the skin.
The following grounding equipment is recommended to prevent electrostatic damage:
●Antistatic tape
●Antistatic smocks, aprons, and sleeve protectors
●Conductive bins and other assembly or soldering aids
●Nonconductive foam
●Conductive tabletop workstations with ground cords of one megohm resistance
●Static-dissipative tables or floor mats with hard ties to the ground
●Field service kits
●Static awareness labels
●Material-handling packages
●Nonconductive plastic bags, tubes, or boxes
●Metal tote boxes
●Electrostatic voltage levels and protective materials
The following table lists the shielding protection provided by antistatic bags and floor mats.
Material Use Voltage protection level
Antistatic plastic Bags 1,500 V
Carbon-loaded plastic Floor mats 7,500 V
Metallized laminate Floor mats 5,000 V
Preliminary replacement requirements 35 
						

							Unknown user password
If the computer you are servicing has an unknown user password, follow these steps to clear the
password.
NOTE:These steps also clear CMOS.
Before disassembling the computer, follow these steps:
1.Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn
the computer on, and then shut it down through the operating system.
2.Disconnect all external devices connected to the computer.
3.Disconnect the power cord.
4.Remove the battery (see 
Battery on page 39).
5.Remove the real-time clock (RTC) battery (see 
RTC battery on page 58).
6.Wait approximately 5 minutes.
7.Replace the RTC battery and reassemble the computer.
8.Connect AC power to the computer. Do not reinsert any batteries at this time.
9.Turn on the computer.
All passwords and all CMOS settings have been cleared.
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							Component replacement procedures
This chapter provides removal and replacement procedures.
There are as many as 47 screws, in 8 different sizes, that must be removed, replaced, or loosened
when servicing the computer. Make special note of each screw size and location during removal and
replacement.
Service tag location
The service tag, affixed to the bottom of the computer, provides information that may be needed
when troubleshooting system problems. The service tag provides the following information:
(1) Product name: This is the product name affixed to the front of the computer.
(2) Serial number (s/n): This is an alphanumeric identifier that is unique to each product.
(3) Part number/Product number (p/n): This number provides specific information about the products
hardware components. The part number helps a service technician to determine what components
and parts are needed.
(4) Model description: This is the number used to locate documents, drivers, and support for
the computer.
(5) Warranty period: This number describes the duration of the warranty period for the computer.
When ordering parts or requesting information, provide the computer serial number and model
description provided on the service tag. When ordering parts or requesting information, provide the
computer serial number and model number located on the bottom of the computer.
Component replacement procedures 37 
						

							Computer feet
DescriptionSpare part number
Rubber Feet Kit (includes 4 base enclosure rubber feet and pen cover) 464821-001
The computer feet are adhesive-backed rubber pads. There are four computer feet (1) that adhere to
the computer base enclosure, and two computer feet (2) that adhere to the high-capacity battery.
38 Chapter 4   Removal and replacement procedures 
						

							Battery
DescriptionSpare part number
8-cell, 73-Wh, 2.55-Ah battery 463650-003
6-cell, 55-Wh, 2.55-Ah battery 441132-003
6-cell, 2.55-Ah battery for use in Japan 534133-291
4-cell, 37-Wh, 2.55-Ah battery 441131-003
Before disassembling the computer, follow these steps:
1.Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn
the computer on, and then shut it down through the operating system.
2.Disconnect all external devices connected to the computer.
3.Disconnect the power cord.
Remove the battery:
1.Turn the computer upside down, with the rear panel toward you.
2.Slide the battery lock latch (1) to the right, and then release it. (The battery disengages from the
computer.)
3.Slide the battery release latch (2) to the left, and then release it.
4.Remove the battery (3) by sliding it straight back.
To install a battery, slide the battery into the battery bay until you hear a click.
Component replacement procedures 39 
						

							Pen
DescriptionSpare part number
Pen593028-001
Before removing the pen, follow these steps:
1.Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn
the computer on, and then shut it down through the operating system.
2.Disconnect all external devices connected to the computer.
3.Disconnect the power cord.
4.Remove the battery (see 
Battery on page 39).
Remove the pen:
1.Position the computer with the left side toward you.
2.Press in on the pen (1) to release it from the pen holder.
3.Remove the pen (2) from the pen holder.
Reverse this procedure to install the pen.
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							Hard drive
DescriptionSpare part number
500-GB, 7200-rpm634924-001
320-GB, 7200-rpm603783-001
320-GB, 5400-rpm622643-001
160-GB, 7200-rpm579045-001
Hard Drive Hardware Kit (includes hard drive bracket, hard drive connector, and hard drive
screws)497744-001
Before removing the hard drive, follow these steps:
1.Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn
the computer on, and then shut it down through the operating system.
2.Disconnect all external devices connected to the computer.
3.Disconnect the power cord.
4.Remove the battery (see 
Battery on page 39).
Remove the hard drive:
1.Position the computer with the front toward you.
2.Loosen the two Phillips PM2.0×5.0 captive screws (1) that secure the hard drive cover to the
computer.
3.Lift the left side of the hard drive cover (2) and swing it to right.
4.Remove the hard drive cover.
NOTE:The hard drive cover is included in the Plastics Kit, spare part number 487926-001.
5.Grasp the Mylar tab (1) on the hard drive and lift the hard drive to disconnect it from the system
board.
Component replacement procedures 41 
						

							6.Remove the hard drive (2) from the hard drive bay.
7.If it is necessary to remove the hard drive bracket and connector, remove the four Phillips
PM3.0×3.0 hard drive bracket screws (1) from each side of the hard drive.
8.Lift the bracket (2) straight up to remove it from the hard drive.
9.Remove the connector (3) from of the hard drive.
Reverse this procedure to reassemble and install the hard drive.
42 Chapter 4   Removal and replacement procedures