Repair Power Sockets

Power Jacks/DC sockets

Ever moved the laptop and forgot you had it plugged in to the mains? Had it on your lap an the dogs tripped on the cable stretched across the room? Or the kids been tugging on it to get a go of the latest game?

Every time the power cable is pulled against the socket on the laptop it stresses the solder joins that connect the socket to the mainboard inside, if these break at any time, even a fine crack will case problems your laptop will stop charging and eventually switch off when the battery power runs down. Usually if your lucky and the break isn't too bad you can move the plug into a certain position and hey presto the power is back on (I'll come back to this later). Other times no amount of wiggling around of the plug will help and you'll have to get it repaired. Worse still the centre pin of the socket breaks and the whole socket needs replacing. If any of the above happen to you, forget phoning the manufacturer to have it repaired under warranty, they won't cover it, they class it as misuse, and they'll probably quote you for a new motherboard, in a lot of cases costing nearly as much as the laptop itself. Still there's always accidental damage cover on your home insurance. You've got some haven't you? Worst comes to the worst just search for "power socket repairs" on your favourite search engine, there are plenty of independent laptop repair companies that will glady resolder a new socket for a lot less.

Going back to the slightly loose socket that when you wiggle the plug you can make it work scenario, let's take a moment to have a look at what's happening here. The fact that it works when the socket is in a specific position tells us that the break in the solder connection is now connected, and when in another position it's disconnected, so what happens when we move it around, well each time we make the connection by wiggling, we cause a spark to arc across the break, which in turn causes heat to build up and a certain amount of burning to occur. Eventually what will happen is that the arcing will cause a hole to be burnt in the systemboard where the solder join is and one day it just won't turn on anymore and the likelyhood is that it will then need the systemboard replacing. The moral here is get it looked at and put right sooner rather than later.

By Christopher Banwell

Drink on Your Laptop

What to Do (and NOT Do) if You Spill a Drink on Your Laptop

Spilling a drink on your laptop can be a very serious problem. But, depending on what you do, and how fast you react, you can potentially save a lot by minimizing the damage a spill can have on your laptop.

What to do in the event of a spill:
Turn off your laptop. If you have your laptop powered on when the spill happens, shut it down as fast as possible. Usually holding the power button down for 10 seconds will be your fastest option to turning off your laptop

Remove the battery. After your laptop has been shut down, remove the battery pack. This will keep your laptop from accidentally being powered back up and removes any way that power can still be going to the motherboard (example hibernation or standby mode)

Leave it opened and turned upside down to dry out. Let gravity be your friend and try to keep the liquid from drying on your components.

Get it repaired and cleaned quickly. Depending on what was spilled on your laptop, the liquid may be corrosive, like cola and can still be doing damage to your laptop. The best defense is sending your laptop in for repair as soon as you can. The quicker you get you laptop into the hands of a professional, the better chance you have of minimizing the damage.

What NOT to do:
Do not turn your laptop back on. A lot of people will make at least one attempt to see if their laptop still works after the spill. This is the worst thing you can do. I can not stress how important it is to keep your laptop turned off, with no power available to it, until it is fixed.

As you can see, your reaction to a spill can minimize the damage that spill can do to your laptop. I have seen laptop repairs from spills range from simple cleaning and diagnostics, to replacing motherboards, and it is easy to tell when the owner handled the spill correctly and when they didn’t.

By Justin Anderson

Online Laptop Repair Guides

Laptops have become a part and parcel of our lives. In keeping with the increasing number of laptops, problems with laptops have also increased multifold. Many people deal with occasional problems with their laptops and repairs have become quite a common necessity now. While the major problems have to be dealt with by authorized service centers, there are minor problems that can be handled on one's own using online laptop repair guides available aplenty on the Internet.

The Internet, as a community, was started and populated first by people who used computers extensively. A lot of the people on the Internet have gone through problems and issues with their computers and laptops that they have not found answers for. Once they did find the answer, they have taken the care to put the answers online on various Web sites and forums on the Internet. These are extremely vital sources to find information one needs to repair one's laptop.

Another thing is the constitution of the laptop. Because of the economy of the space involved, they are made quite compact, and the laptops have areas earmarked for various things. For instance, every laptop has a battery that can be easily detached without touching the rest of the laptop or opening a screw. Also the RAM of a laptop is usually inserted in a place that is easily accessible so that it can be changed and upgraded when necessary.

However, while going in for online laptop repair guides, one must remember that not all problems can be solved with little effort and not everyone can repair a laptop on their own. A laptop, after all, is a complex machine with a lot of interconnected parts. While repairing a laptop, first of all one needs to do a proper diagnosis of the problem. If this is not done, faulty repairs can cause irreparable damage.
Only one who has considerable and practical experience with laptops and their configuration should consult Internet sites for repair guides.

Since most laptops are different from others, laptop manufacturers provide repair guides on the internet that one can refer to in case of a problem with the laptop. One can also find individuals posting such repair guides. One search with major search engines will throw open a plethora of options regarding online laptop repair guides and you can easily save that extra repairing cost.

By Seth Miller

Laptop DC Jack Repair

By far, the most common piece of hardware to fail on any laptop is the DC Jack (the plug that accepts power on the laptop). There are several reasons for the high failure rate but the two most common are poor handling and poor design. I would say over 90% of these DC jacks are soldered right on to the motherboard.

Every day abuse of plugging and unplugging the AC power source wears down the solder connections on the motherboard.

Here are the two common symptoms for this damage:
- Laptop will not accept external AC Power. Constantly remains on battery, till the battery dies. - You have keep moving the cord around till it starts accepting external power.

First thing you need to do is eliminate the cord/power supply as being the source of problems. The power supply is the box right on the AC cord. Some power supplies have an indicator light to show when they are plugged in. If the light is working then it is not the power supply. If your power supply does not have the indicator light get a voltmeter, plug the laptop cord into the wall and using a voltmeter check the end that goes to the laptop. Insert one lead inside the opening and place the second lead on the outside. Make sure your meter is set to read DC Volts. Now if you get a reading, depending on the laptop will be be somewhere between 14 to 19 volts then your power supply is good and the damage is to the DC jack on the laptop motherboard.

Repairing the DC jack on any laptop is a major repair. If you do not feel comfortable doing it please contact a person who is qualified for the job. This repair will require dismantling the whole notebook, and removing the motherboard. Please read the following article on what steps should be taken to ensure proper care when disassembling a notebook: Notebook Repair.

Once you have complete access to the DC Jack you will see the pins that get soldered to the motherboard. To the naked eye it might look like nothing is wrong with them, but a slight break in the solder will cause these problems. You will need a soldering iron with a very fine tip. The fine tip is to avoid damage to adjacent components. Apply the solder to each pin making sure the solder gets evenly spread. The solder should have a dull look to it when you are done.

Once you have soldered all the pins, reassemble the notebook and test it out. To avoid this damage in the future take extra care when inserting and removing the external power cable. Hope this helps!

By John Vizaniaris

Laptop Hardware Repair

A laptop is essential for students and working individuals. Because of its portability, users can write important papers, connect to the Internet via wireless modems, and can even watch movies anytime and anywhere. But without proper care, this machine can break down, and especially, there can be problems with the LCD monitor.

Here are some tips that can help you in troubleshooting your laptop's LCD monitor.
Is there something wrong with your screen? If this is so, then there is a possibility that the LCD (liquid crystal display) backlight of your laptop is broken. The LCD backlight is the source of light that gives you a clearer visual of your screen.

Symptoms of LCD damage include:

- Dim laptop LCD
- Flickering screen

- Faint images on your LCD

- No video image

- Faded laptop LCD

A laptop backlight is composed of four parts and these are:

- Laptop inverter

- LCD lamp

- Inverter cable

- Toggle switch

Damage to any of these parts may result to the symptoms stated above. Unfortunately, there is no other way to be sure if one of these parts are damaged without using a tester. Some of the main causes of damage to these parts include age and excessive use of your laptop. Parts such as the LCD lamp usually last for two years minimum.

Aside from the blacklight, it is possible that your LCD screen itself is damaged. This problem can be very serious because the LCD is the most fragile and expensive part of your laptop.

Symptoms of LCD damage include:

- Decolorization of your screen

- Appearance of stripes or lines on your screen

LCD damage is usually caused by hard impacts to your laptop. Remember, the LCD is a very sensitive and fragile piece of equipment. Even the slightest amount of pressure on your LCD can cause it to break.

The only way to repair the backlight and the LCD monitor is to replace them. Replacing the LCD monitor alone can cost you around $250 and that is apart from the $120 service fee that most laptop repair companies charge.

By Seth Miller

Laptop Repair and Upgrade

Laptop repair isnt always easy, but sometimes it can be. If the laptop isnt under warranty and you dont feel comfortable replacing some of these parts yourself, youll have to find a professional to do it. If you only want to upgrade then you cant send it back to the manufacturer and you'll have to find a tech to do it. You can bring it to a well known retailer like Best Buy and have their Geek Squad work on it since they're pretty well trained and always do a good job on repairs, or you can find a professional someplace else to do it for you.

Easy to replace parts:
Wireless adapter- if your wireless stops working for some reason, you can just go out and get a USB wireless adapter or a PCMCIA wireless adapter to put in the card slot.

RAM/Memory-

Memory is pretty easy to install and fairly inexpensive. In many cases, you can drastically improve the performance of your laptop just by adding some more memory. Most places that sell laptops can install it for you, or if you feel comfortable installing it yourself you can put it in. There's an enclosure on the bottom that you unscrew in order to install the memory.

Hard Drive:

A hard drive can be a little more tricky to upgrade. If your hard drive gets corrupted, youll probably lose most of your data unless a professional can recover it. Then you'd just have to toss it out and buy a new one and have it installed. The #1 reason for hard drive corruption is abuse, so be careful with your laptop if you wanna keep your hard drive safe. If you just want to uprgrade to have more space, first youd need to back up your data and then take the old drive out and put the new one in. A hard drive upgrade is similar to a RAM upgrade. There is an enclosure usually on the bottom that contains the hard drive. In Gateway laptops it's usually in the front for easy access.

Not so easy to replace parts:
For these repairs you'll definitely have to take it to a professional, or sometimes it'll actually be more worth it and less hassle just to junk it and buy a new one

CPU:

If you want to upgrade the CPU in your laptop, you're going to have a hard time because usually the motherboard has to be changed as well. You'd be better off just buying a new laptop. On the other hand, if your processor goes bad for some strange reason and you want to install the same one or even a higher speed version of the same processor, it is doable. Youll probably have to ship it out or find a professional to do this.

Motherboard: Upgrading or replacing the motherboard can be a hassle as well, and costly. Again, you'd probably be better off just buying a new laptop unless you have a good warranty and you're willing to go through the hassle of shipping it out.

Keyboard Keys:

When a key pops off the keyboard, it usually cant be put back on, so if your laptop is under warranty youll need to send it out for repair. Otherwise you can take it to a tech and have them order the keys you need.

Graphics card:

Since laptops dont have as much room as a desktop computer, the graphics card is usually integrated onto the motherboard. If you really think it's worth it to spend the money and replace the guts of your laptop, go right ahead. Otherwise I'd say buy a new laptop with a very good graphics card so you'll never feel the need to upgrade.

Various other upgrades and add-ons can be done through USB or the PCMCIA card slot. For example, if you get more involved with things like sound and video, there are certain expansion cards you can buy depending on what you're trying to accomplish. They're usually plug and play and very easy to install.

By Michael LaRocco

Laptop Motherboard Repair

A laptop is a simple and compact computer. Yet, its compactness is the reason for its intricacies and complications. For instance, while most normal PCs have a mother board that has different ports for different other components of the computer to be attached, a laptop on the other hand, has a mother board that has a lot of things that are built into it, instead of sections where other parts can be attached. An example here can be given of a sound card, which often comes as a separate part for older PCs and has to be attached to the motherboard of a computer. However, the sound and video display card is integrated with the mother board in case of the laptop.

It is for these reasons that the motherboard is perhaps the most important part of a laptop after the processor. It is also not easy to repair a laptop motherboard because of its immense intricacies. While repairing a motherboard one has to be extremely careful and cautious.

Whenever a problem is arises with a motherboard, one should not take the risk of repairing it themselves since if it is not done properly it can lead to irreparable damage to the entire laptop. It is usually safe to approach a dealer of a laptop for the repair of its motherboard. They have technicians who have an expertise in dealing with laptop motherboard problems and can make the right diagnosis and carry out repairs.

There are many self employed people who repair laptops and are often a much cheaper option. One can approach them to repair their motherboard, but a few things should be kept in mind. The most important is to know their experience in repairing laptop motherboards. Let them not convince and fool you by saying that they have repaired many PC motherboards since laptops and PCs are a different thing all together.

Secondly one needs to ask them whether they have previously repaired laptops of the make that you have. If they have done so, they would be aware of the intricacies of the work and can be a safe bet for laptop motherboard repairs.

Laptop motherboard repair needs expertise and experience and it is best left to the experts.

By Seth Miller

Laptop Battery Repair

The greatest strength of a laptop is its portability and the fact that it can be used without needing any external power connections for hours at a time. This makes a laptop battery one of the most important parts in a laptop. It is very important, hence to take care of a laptop battery. Like every other part of the laptop, the battery also undergoes wear and tear and might need repairs.

It must be remembered that most laptop batteries cannot be repaired if damaged. This is because of their complex construction. And even if it were to be repaired, one would need specific and expensive instruments to do so. It is for this reason that often it is suggested that if a battery is damaged, one should buy a new laptop battery, rather than repairing a damaged one. This is often a better and a cheaper idea.

At times when we see the need for a laptop battery repair, it turns out that all it requires is a bit of calibration. This is done in most battery or laptop repair shops locally. However, there are cases when the battery is actually damaged. It then needs thorough repair, or should simply be replaced, as mentioned above.

One needs to remember that it is not a good idea to use a laptop battery that has begun to leak. Do not even think of repairing such a battery as it could be dangerous. Such laptop batteries can usually not be repaired and even if they are, the repairs are expensive and the battery may not be safe to reuse.

However, there are different types of batteries that are available on the market, and quite a few of them even lend themselves to repair in case of damage. One first needs to know the type of battery one has before one goes in for a laptop battery repair. One can then check it out in some local stores. Often the internet is a good source for finding out information regarding the same and also to know whether the laptop battery can really be repaired in the first place.

By Seth Miller

Guide to Laptop Repair

Dropping your laptop or accidentally spilling coffee over it can cause serious damage. If this happens, you have to get it repaired quickly to avoid more serious damage. But where do you get it fixed? How much will it cost you? What will happen to all the data in your laptop? Let this article guide you in what to do with your damaged laptop.

Where do I bring it for repair?
If you do not trust just anyone in handling your precious laptop, then you can always send it back to the manufacturer. These companies have a service department that will cater to all your laptop repair needs. Unless your warranty from the manufacturers is still valid, these repair services can cost you around $500 dollars for a broken motherboards and $400 for a cracked screen. It may be expensive, but at least you will be assured of quality service. If you do not have that kind of money for repairs, then you can turn to the Internet to look for a laptop repair company that charges cheaper rates. Be sure to check their rates carefully to ensure that they will not be charging you with any hidden fees.

How long will it take?
The amount of time required to fix the laptop depends on the type of laptop, as well as the nature of the problem. If you are using a laptop manufactured by a famous company, then the parts of these models will be easy to get. But if you are using a less-known laptop, then you may need to wait a bit to give the repair company time to look for a replacement part. In general, laptop repairs take a week.

What will happen to all the data in my laptop?
If the damage of your laptop is disc-related, then there is a possibility that all your data may be lost. But not to worry because there are programs that can retrieve the data from your laptop and store it in a backup. If the damage to your laptop is simply a hardware issue, such as a faulty screen, then there is no need to worry about losing your data.

By Seth Miller

Wi-Fi Technology

Wi-Fi

Wi-Fi, also, WiFi, Wi-fi or wifi, is a brand originally licensed by the Wi-Fi Alliance to describe the underlying technology of wireless local area networks (WLAN) based on the IEEE 802.11 specifications.

Wi-Fi was developed to be used for mobile computing devices, such as laptops, in LANs, but is now increasingly used for more applications, including Internet and VoIP phone access, gaming, and basic connectivity of consumer electronics such as televisions and DVD players, or digital cameras. There are even more standards in development that will allow Wi-Fi to be used by cars in highways in support of an Intelligent Transportation System to increase safety, gather statistics, and enable mobile commerce IEEE 802.11p.

A person with a Wi-Fi device, such as a computer, telephone, or personal digital assistant (PDA) can connect to the Internet when in proximity of an access point. The region covered by one or several access points is called a hotspot. Hotspots can range from a single room to many square miles of overlapping hotspots. Wi-Fi can also be used to create a Wireless mesh network. Both architectures are used in Wireless community network, municipal wireless networks like Wireless Philadelphia, and metro-scale networks like M-Taipei.

Wi-Fi also allows connectivity in peer-to-peer mode, which enables devices to connect directly with each other. This connectivity mode is useful in consumer electronics and gaming applications.
When the technology was first commercialized there were many problems because consumers could not be sure that products from different vendors would work together. The Wi-Fi Alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created another brand "Wi-Fi CERTIFIED" to denote products are interoperable with other products displaying the "Wi-Fi CERTIFIED" brand.

Wi-Fi: How it works
A typical Wi-Fi setup contains one or more Access Points (APs) and one or more clients An AP broadcasts its SSID (Service Set Identifier, "Network name") via packets that are called beacons, which are broadcast every 100 ms. The beacons are transmitted at 1 Mbit/s, and are of relatively short duration and therefore do not have a significant influence on performance. Since 1 Mbit/s is the lowest rate of Wi-Fi it assures that the client who receives the beacon can communicate at least 1 Mbit/s. Based on the settings (e.g. the SSID), the client may decide whether to connect to an AP. Also the firmware running on the client Wi-Fi card is of influence. Say two APs of the same SSID are in range of the client, the firmware may decide based on signal strength to which of the two APs it will connect. The Wi-Fi standard leaves connection criteria and roaming totally open to the client. This is a strength of Wi-Fi, but also means that one wireless adapter may perform substantially better than the other. Since Wi-Fi transmits in the air, it has the same properties as a non-switched ethernet network. Even collisions can therefore appear like in non-switched ethernet LAN's.

Channels
Except for 802.11a, which operates at 5 GHz, Wi-Fi uses the spectrum near 2.4 GHz, which is standardized and unlicensed by international agreement, although the exact frequency allocations vary slightly in different parts of the world, as does maximum permitted power. However, channel numbers are standardized by frequency throughout the world, so authorized frequencies can be identified by channel numbers.

The frequencies for 802.11 b/g span 2.400 GHz to 2.487 GHz. Each channel is 22 MHz wide and 5 MHz spacers between the channels are required.

The maximum number of available channels for wi-fi enabled devices are 13 for europe, 11 for North America and 14 for Japan

Src Wikipedia

BlueTooth Technology

Bluetooth is the name given to a new technology standard using short-range radio links, intended to replace the cable(s) connecting portable and fixed electronic devices. The standard defines a uniform structure for a wide range of devices to communicate with each other.

Its important features of Bluetooth are robustness, low complexity, low power and low cost. Bluetooth is considered a wireless PAN technology that offers fast and reliable transmission for both voice and data. Bluetooth offers wireless access to LANs, PSTN, the mobile phone network and the Internet for home or office and other hand held devices.

A complete Bluetooth system will require these elements:
An RF portion for collecting and sending data or information:
A module with a baseband microprocessor for processing function

Memory module
An interface to the electronic device (such as a mobile phone, camera, or PC)
The lower-layer Bluetooth protocols are normally embedded in the baseband module, and the host processor must support the upper-layer protocols (like file transfer). In other words, the RF/baseband solution provides the means to communicate with the host, but need to implement a connection interface, as well as any upper-layer protocols, to use applications supported by the final product.

The higher/upper layers of the Bluetooth technology called as the Bluetooth profiles and these are nothing but a set of protocols. These protocols are optimized for particular applications. In the case of file transfer between two devices, it requires interoperability among devices. Each of the linked devices needs to have similar applications ensures interoperability across a spectrum of devices.

The Bluetooth stack:

It has the following components:

RF portion for reception and transmission
Baseband portion with micro controller
Link control unit
Link manager to support lower-layer protocols
Interface to the host device
Host processor to support upper-layer protocols
L2CAP to support upper-layer protocols

The radio frequency (RF) portion provides the digital signal-processing (DSP) component of the system, and the baseband micro controller processes these signals. The link controller handles all the baseband functions and supports the link manager. It sends and receives data, identifies the sending device, performs authentication, and determines the type of frame to use for sending a transmissions. The link controller also directs how devices listen for transmissions from other devices and can move devices into sleep state in order to save power.

The link manager, located on top of the link controller, controls setup, authentication, link configuration, and other low-level protocols. Together, the baseband and the link manager establish connections for the network.

The host controller interface (HCI) communicates the lower-layer protocols to the host device(Like mobile phone, hand held PC etc). The host contains a processor.

L2CAP: it supports the upper-layer protocols and communicates with the lower layers. The Higher/upper-layer protocols consist of service-specific applications that must be integrated into the host application as explained above. RFCOMM protocol, which allows for the emulation of serial ports over the L2CAP, which is also an important part of Bluetooth.

The Service Discovery Protocol (SDP) gives the required services and the properties and characteristic of the service that a particular Bluetooth device is made for.
The ACL Link: Bluetooth uses five logical channels to support transferring of information between devices:

Core Protocols in Bluetooth:

Baseband:
The Baseband and Link Control layer enables the physical RF link between Bluetooth forming a piconet It provides two different kind of physical links with their corresponding baseband packets, Synchronous Connection-Oriented and Asynchronous Connectionless which can be transmitted in a multiplexing manner on the same RF link.Asynchronous Connectionless (ACL) packets are used for the transmission of data only while Synchronous Connection-Oriented can contain either audio or a combination of audio and information.

Link Manager Protocol:
The link manager protocol is responsible for link set-up between Bluetooth devices. This includes setting up of security functions like authentication and encryption by generating, exchanging and checking of link and encryption keys and the control, negotiation of baseband packet sizes and duty cycles of the Bluetooth radio device, and the receiving device on the other end.

Logical Link Control and Adaptation Protocol:
The Bluetooth logical link control and adaptation protocol (L2CAP) adapts upper layer protocols over the baseband. It can be thought to work in parallel with LMP in difference that L2CAP provides services to the upper layer when the payload data is never sent at LMP messages.

Service Discovery Protocol:
Using SDP, device information, services and the characteristics of the services can be queried and after that, a connection between two or more Bluetooth devices can be established.

Telephony and Cable Replacement Protocol:
Telephony Control protocol: Binary (TCS Binary or TCS BIN), a bit oriented protocol, defines the call control signaling for the establishment of speech and data calls between Bluetooth devices.
RFCOMM: It is a serial line emulation protocol and is based on ETSI 07.10 ( European Telecommunications Standardization Institute ) specification. This protocol emulates RS-232 control and data signals over Bluetooth baseband, providing both transport capabilities for upper level services that use serial line as transport mechanism.

Adopted Protocols:

PPP
PPP is the IETF Point-to-Point Protocol (Internet Engineering Task Force, IETF Directory List of RFCs) and PPP-Networking is the means of taking IP packets to/from the PPP layer and placing them onto the LAN.

TCP/UDP/IP
TCP/IP/PPP is used for the all Internet Bridge usage scenarios in Bluetooth 1.0 and for OBEX in future versions. UDP/IP/PPP is also available as transport for WAP.

OBEX Protocol
IrOBEX (Short name is OBEX) is a session protocol developed by the Infrared Data Association (IrDA) to exchange data in a simple and automatic way.

Advantages:
Using peer-to-peer connectivity, Bluetooth technology simplifies personal area wireless connections, enabling all digital devices to communicate automatically. Bluetooth technology also provides fast, secure voice and data transmissions. The range for connectivity is less than 10 meters, and line of sight is not required. The Bluetooth radio unit can functions even in noisy radio environments, ensuring audible voice transmissions in severe conditions. It can protect data by using error-correction methods and provides a high transmission rate. It is possible encryption and authentication for privacy in the transmitted data.

In Bluetooth ad hoc networking enables personal devices to automatically exchange information and synchronize with each other.

By Jith Crs

LCD

What is LCD

A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices.

Each pixel consists of a layer of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other.

How It Works
Before applying an electrical charge, the liquid crystal molecules are in a relaxed state. Charges on the molecules cause these molecules to align themselves with microscopic grooves on the electrodes. The grooves on the two electrodes are perpendicular, so the molecules arrange themselves in a helical structure, or twist (the "crystal"). Light passing through one filter is rotated as it passes through the liquid crystal, allowing it to pass through the second polarized filter. Half of the light is absorbed by the first polarizing filter, but otherwise the entire assembly is transparent.

When an electrical charge is applied to the electrodes, the molecules of the liquid crystal are pulled parallel to the electric field, thus reducing the rotation of the entering light. If the liquid crystals are completely untwisted, light passing through them will be polarized perpendicular to the second filter, and thus be completely blocked The pixel will appear unlit. By controlling the twist of the liquid crystals in each pixel, light can be allowed to pass through in varying amounts, correspondingly illuminating the pixel.

It is normal to align the polarizing filters so that pixels are transparent when relaxed and become opaque in the presence of an electric field, however the opposite is sometimes done for special effect.

The electric field necessary to align the liquid crystal molecules rapidly is also enough to pull them out of position, damaging the display. This is solved by using an alternating current to rapidly pull the molecules in alternate directions.

To save cost in the electronics, LCDs are often multiplexed. In a multiplexed display, electrodes on one side of the display are grouped and wired together (say, in columns), and each group gets its own voltage source. On the other side, the electrodes are also grouped (say, in rows), with each group getting a voltage sink. The groups are designed so each pixel has a unique, unshared combination of source and sink. The electronics, or the software driving the electronics then turns on sinks in sequence, and drives sources for the pixels of each sink.

Important factors to consider when evaluating an LCD monitor include resolution, viewable size, response time (sync rate), matrix type (passive or active), viewing angle, color support, brightness and contrast ratio, aspect ratio, and input ports (e.g. DVI or VGA).

Src Wikipedia

Used Laptops

What Are Used Laptops?

Used laptops are those that have been used by a consumer for any length of time and then resold. Even if computers are only one day old, stores cannot sell them as new laptops, they become used laptops.

What Are Refurbished Laptops?
A refurbished laptop is a computer that has been used anywhere from 1 to 90 days, and then returned to the store or manufacturer who then resells it, or repairs and replaces any needed parts in order to sell it. Some of these refurbished computers may be just as good as new computers, but you can get them at a much lower price.

What To Look For When Buying Used Laptop

1. Condition
The first thing that you should look at is the used computer’s condition. It has been recommended to stay away from laptops that are over 3 years old. The system will be outdated and may not be able to run some of the software and programs that are currently available. You may even want to stick to laptops that are less than 18 months old. Refurbished laptops do not have some of these concerns because they are newer and have been repaired and tuned up.

2. Features
The features offered on used laptops are the next important factor you should take under consideration If you need speed, you need to keep in mind that used laptops run slower than desktops with the same processing systems. Do not buy used laptops with less than 128 MB of memory; it may not be able to run many of the applications and programs that are standard in today’s computers. You can get used laptops that are powered by anywhere from 20 GB to 80 GB depending on your processing and computing needs. The screen size, definition, and resolution are other important issues in laptops. Make sure that the laptop you are looking at has the capabilities to do what you need it to do media and entertainment-wise.

3. Portability
Portability of laptops is also an important issue. Laptops are getting thinner and lighter every day. Does the laptop you are looking at weigh a lot? Make sure you add in the weight of the case and any other accessories you will be carrying.

When buying used laptops from a private seller or an acquaintance, be careful. Have the used laptops checked out thoroughly by a neutral party or professional. Every good bargain shopper knows that you can find deals by shopping for pre-owned items. Laptop computers are no exception. Educate yourself on your wants and needs and you will get what you want.

By Margarette Tustle

Refurbished Laptops

What exactly is a refurbished laptop

Here's the short answer. Someone buys a new laptop from a chain store, takes it home for a few days, or a couple of weeks. Then for one reason, or another decides they don't need it, or can't afford it. Usually within 30 days(depends on store policy) returns the notebook PC and gets a full refund of their money. The store cannot sell it as new anymore.

So what happens to it?
The laptop computer is sent to the original manufacturer for store credit. Now the manufacturer has to do something with it, so they begin the refurbish process (which means to refresh, or make bright again). The company goes through every detail to make sure the laptop works properly and looks new, but it must be labeled refurbished. It is then distributed through the economy sometimes at over the half off the new price.

Refurbished laptops come in at almost 60% off the original retail price. The difference between a new laptop computer and a reconditioned one could be several hundred dollars. Saving money in today's world just got a little easier. Have you noticed natural gas and regular gas growing up about 50%? Surely you have, unless you live on the moon! Refurbished notebooks have become totally expectable in our society because people are seeing extra savings buying something a little used
Refurbished Laptops sales are growing at an alarming rate. Companies and business owners are having trouble keeping them stocked. Why? The answer is easy. They save people money and lots of it!

At one time, or another most of the U.S. population has bought something used because they saw the difference in price. Those who did felt they didn't need to keep up with the Jones' and put the savings where they needed it. Buying used just shows how savvy a person is with their money and buying refurbished notebooks is a smart thing to do.

Many students and business professionals need to stay mobile and must keep their notebook PC as current as possible to operate today's technology. The downside is it can be very expensive. Now it doesn't have to cost a fortune to keep up with current technology and stay mobile. Refurbished laptops provide the freedom from wires, and the ability to do almost anything, anywhere without the high price of a new mobile computer.

By M Johnson

Laptop Memory

The more laptop memory you have in a laptop the better, but there are other issues involving memory in laptops. Laptops are usually more limited in the amount of memory a system can handle. If in the future, you plan to upgrade your laptop RAM, gaining access to the memory can also be a problem.

Do You Have Enough Laptop RAM?
When determining if a system has enough memory or not, look at the minimum and recommended requirements for the software you intend to run. Most software today will list what are the minimum requirements of a system to run that software. It should also list what specifications it recommends to run the software. With applications becoming more memory hungry, I think the minimum amount of RAM these days for any system would be 256MB. Better still if you have 512MB, and for the best performance 1GB or higher.

What Are The Restrictions?
Most laptop computers usually only have two slots available for memory modules, which means you are limited to the amount of memory available. What this means is you are restricted to 1GB or 2GB’s of RAM, based on 512MB or 1GB memory modules

Some Tips
If you are about to buy a new laptop, find out what is the maximum amount of laptop memory your new system will take. Go to the laptop manufacturer’s website and the information should be listed there. This is important for the future, because doubling the amount of RAM in your system at a later date can give you quite a performance boost.

Can I Install It Myself?
Most laptops today have a small door on the bottom of the unit which gives you access to the memory slots, although some memory can be located beneath the keyboard of some laptops. Don’t be discouraged if your memory is located below the keyboard, as the process of taking out the keyboard and installing more memory is not that difficult. If you have a system that is relatively new, check to see that any upgrades you do yourself, does not void your warranty.

By Elizabeth Lord

Business Laptop

Should I buy a laptop or a desktop PC?

Before we discuss what to look for in a business laptop, you should figure out whether you need a laptop at all. Desktop PCs typically cost hundreds of dollars less than laptops and if you're able to do all of your business comfortably from one location, you need not shell out extra cash for a portable form factor.

What advantages does a laptop offer?
A portable computer provides access to your files and applications wherever you are -- every corner of the world becomes an extension of your office. Riding the train or sitting in an airport, you can be just as productive as if you were sitting in your desk chair.

Your laptop can handle much more than just email, spreadsheets, and word processing. Here are a few of the roles a laptop can fill:

Presentation maker: Display your PowerPoint deck anywhere, anytime.

DVD player: Whether you're waiting in the terminal or on the plane itself, watching a movie makes flying much more entertaining.

Gaming machine: The most powerful business laptops are primed for gaming on the go.
Jukebox: Invest in Internet radio, a CD drive and a big hard drive for MP3s You'll never be without your music collection.

What are the disadvantages to using a laptop?
On top of the premium price tag, there are a few other drawbacks to buying a laptop rather than a desktop PC. For one, laptops are not as easy or inexpensive to upgrade as their desktop brethren. While it's relatively simple to add a bigger hard drive or a DVD burner to a desktop, on a laptop the operation can be more expensive, more complicated, or both. Here are a few other limitations to note:

You'll be working on a smaller keyboard, looking at a smaller screen and probably sitting in a less-than-ergonomic position.

You'll have to become conscious of battery life, an issue the desktop PC user doesn't have to worry about.

You'll need a separate network hub and a backup solution. Laptops aren't optimised for those functions.

Are there hidden, recurring, or long-term costs of owning a laptop?
Because a laptop is likely to log many more miles than a desktop PC, it's inherently more vulnerable to wear and tear. You'll be susceptible to ailments such as worn-out hinges, broken keys, busted screens, and mangled optical drives. In the past, nearly all business laptops came with a standard three-year warranty on parts and labour. These days, some models include only a one-year warranty with the option to purchase an upgrade. Read your warranty information carefully before you make a purchase. Also, a decent laptop bag will help reduce laptop deterioration.

By Justin Jaffe

Gaming Laptop

The gaming laptop is coming of age! It is steadily increasing in popularity as performance quality goes up. Gamers now regularly consider laptops or notebooks when searching for that perfect gaming machine.

With each new generation of notebooks we are seeing some novel breakthroughs: dual core notebooks, PCI Express, Sonoma chipset, increased storage, increased RAM, faster CPUs, better battery life and better wireless connections including a Cellular Modem. All welcome news for gamers and notebook lovers alike.

Generally, gamers are a very demanding group, they know their computers and they know what they want in their computers. Most gamers like to order their gaming laptop with their own specs and configurations. In that light, if you closely examine the main points gamers consider when configuring or building their Dream Machine -- you will have a good blueprint for the best gaming machine.
Since notebook technology changes every two years or so, it's probably wise to purchase a laptop that can be easily upgraded as new products come on line. So consider the upgradable factor in any notebook that you plan to buy..

Now, lets look at some of these key gaming factors:

GRAPHICS
You must have the best/latest/fastest Graphics on the market. DUH!
Serious gamers are concerned with graphics, obsessed would probably be a better word. And rightly so! Graphics or the quality of the graphic chipset in your notebook computer will be your first area of consideration and it will greatly determine the gaming performance of your PC.

Go with the latest Graphic Chipset and also check to see if you can upgrade your Graphics Card on the particular machine you're thinking about buying. Many machines allow this.

Here are some Graphic Chipsets that are highly rated: ATi Mobility Radeon 9700, ATI's Mobility FireGL V3200 or Intel's Graphics Media Accelerator 900.

ATi Mobility Radeon 9700 is a high quality Graphics Card or visual processing unit (VPU) present in many next generation notebooks. It will give you higher performance at a lower power level, saving battery power.

It makes your notebook computer capable of many functions: 3D games, wide-screen HDTV, dynamic presentations, mobile video editing studio and graphic processor.

Many notebooks now come with integrated graphics, where components interact and are sometimes shared, especially memory. If you want a notebook computer for 3D games -- check the amount of video RAM -- this is memory that's dedicated to graphic or video applications.

Other common graphic chipsets are: STMicro, NVIDIA, 3D Labs, Matrox, Trident S3 and SIS.

RAM
Get the largest amount of RAM possible. DUDE!
RAM or random-access memory will determine how much graphics your notebook computer will be able to handle. It's best to get the largest amount possible on your machine or what you can afford.
It's generally agreed that you need at least 256MB for Windows XP and Mac OS X. You will only need 128MB for other operating systems in Windows or Mac.

RAM or the amount of RAM on your notebook computer is extremely important if you want to handle heavy graphic files or want to play games on your notebook. The more RAM you have, the more applications you will be able to handle. Some notebook now come with up to 2GB of DDR2 533MHz RAM!

DDR2 SDRAM - is a new standard that can boost conventional SDRAM memory up to speeds well over 200MHz and beyond. For example, the IBM ThinkPad T43, thanks to the Sonoma Chipset or platform has 533MHz DDR 2 SDRAM.

This is much better than standard SDRAM which tops out around 150- 166MHz and DDR SDRAM which starts at 200MHz and goes up to around 400MHz.

Video RAM or VRAM is special memory that's used by video adapters on your notebook. This is RAM that is dedicated to handling the visuals and graphics on your notebook computer. This is helpful if you want to play a lot of the latest 3D video games on your notebook.

It is somewhat different from ordinary RAM because it can be accessed by two different devices at once -- enabling screen updates while the video processor processes new data VRAM provides better graphics but is more expensive than ordinary RAM.

SPEED
You need the fastest computer money can buy. Period!
In order to get the maximum performance from your ultimate gaming computer you must have the fastest speed you can get or afford. Your ultimate PC must be able to process and handle the latest 3D video games with ease. There is nothing as annoying as your PC freezing up in the middle of some major gaming action!

Therefore, your Processor's speed is very important.
CPU or Central Processing Unit, you probably know it as the processor! It's the heart or rather the brain of your notebook or computer. It does all your computer's data processing and applications. Since it does most of the work, it's usually the most expensive part of your notebook computer.
Go with SATA!

SATA is a type of hard drive and stands for Serial Advanced Technology Architecture. It was developed by a whole group of companies including Seagate, Intel, Maxtor, Dell and others. SATA transmit data in a serially (in a single stream) as opposed to PATA or Parallel ATA which is commonly referred to as an IDE hard drive.

Serial ATA hard drives uses less power and are ideal for notebook computers, they are also more advanced than PATA hard drives which uses multipe streams of data -- go figure! But Serial Technology carries data in a single stream and unlike PATA is not limited to a particular clock speed, Serial transfers data packets almost 30 times faster than parallel.

If top performance in your notebook is one of your goals, go with a SATA hard drive.
The speed of microprocessors is measured in MHz.

MHz is short for megahertz. One MHz equals one million cycles per second. The speed of processors, usually known as clock speed, is measured in megahertz (MHz) or these days in gigahertz (GHz).
The higher the clock speed, the faster the computer will process applications and data. It determines how powerful your notebook computer will be. Processor speeds for notebooks or laptops are steadily increasing, not quite the same as a desktop but the gap is narrowing quickly. Speeds of 3.4GHz or more.

Don't forget to ask or check the hard drive speed! A 7,200rpm hard drive is faster than a 4,200rpm or 5,400rpm and usually gives better performance.

DISPLAY
You need the sharpest, brightest display screen or all the above points are moot!
Display quality is also extremely important to your gaming experience. Make sure the resolution and display quality of your notebook computer can handle the graphics for 3D Gaming.

What to keep in mind...
SVGA Resolution. Put simply, computer images are made up of dots, the more dots you have -- the better the image. SVGA Resolution is made up of 800 x 600 dots.

Many notebook computer have XGA (1024 by 768 dots) or SXGA (1280 x 1024 dots), these resolutions will give a higher quality image. WXGA stands for widescreen XGA.
TFT Active Matrix Display. TFT stands for thin-film transistors and many high-end notebook computers use (TFT) active matrix liquid crystal displays.

If display quality is your main reason for buying a notebook, it's best to give it the 'old eye test' and check out the image quality first-hand and decide for yourself. Panasonic, Toshiba, Sony, and others are known for their high quality monitors -- this quality is also present in their notebook display screens.

So when buying your perfect Gaming Notebook Remember This:
Graphics + Ram + Speed + Display = Perfect Gaming Notebook
Consider all of the above factors before you buy or config your perfect gaming machine. Chances are high that you will get a top-notch quality Gaming Notebook that will give you hours and hours of pure gaming bliss!

By Titus Hoskins

Laptop Security

Laptop Security Devices
As an administrator, and ultimately the person responsible for the information and laptop security within your organization, “Stolen Laptop” is the last two words you want to hear. Unfortunately, statically this is going to happen and if you have not put into place a laptop security policy you will wish that you had.

Laptop Security Cables
Laptop Security Cables are the number one purchased laptop security devices. People often do not have a clear understanding of what level of security, laptop cables provide. A laptop security cable will not work if it is not used. A laptop security policy that requires that they be used is necessary to achieve the protection the home office is looking to achieve. The small plastic security slot where they attach offers minimal protection and additionally the cables really aren’t that difficult to cut. So, why are they the number one solution? They provide a visual theft deterrent. We have found that visual laptop computer security solutions are very effective and when it comes down to it economically they are most effective.

Security Plate
Security plates provide an effective visual deterrent solution as well and are the second most commonly used laptop security theft deterrent The Plate is probably the least expensive solution and takes us one step toward laptop recovery as well. If your laptop has a Security Plate, placed visibly on the top of the laptop, you gain big strides in the possibility of getting your laptop computer and the information on your laptop back. If you put both or either of these two products into your laptop security policy you will have followed in the steps of some of the largest corporations and government agencies in this country.

Laptop Security Softwares
With laptop theft deterrent solutions in place we want to look at recovery and data protection commonly provided by using some form of laptop security software. There are many softwares which You can get for the purpose of laptop security related to your data.

Ultimately when it comes to laptop security there really aren’t that many effective solutions. Putting a security policy together that addresses deterring the laptop theft helps to protect your property and your information. By utilizing a few additional laptop security software tools you help insure greater protection of your company’s data.

By Tom Goll

Laptop Cases

There are various laptop cases which cater to the numerous models of available laptops. Although many laptops come with a case, they are not up to the mark, being either too small or too bulky for use. Laptop cases are most required by those who travel a lot and tend to carry around their laptop, and of course for those who want to maintain the look and the safety of the pc.

Types of Laptop Cases
There are a variety of laptop cases available on the market; one just has to buy according to one’s needs.

There are aluminum laptop cases,

Leather laptop cases

Feminine women’s laptop cases.

How to Choose
When choosing the right laptop case, one first has to determine the size of the laptop it’s going to carry. The important thing is for the laptop to fit easily and snugly into the laptop case, so choose wisely Not only are there different-sized laptop cases, the styles and price also vary accordingly. There are basic neoprene-sleeved laptop cases and also the actual hard-shell laptop case. Laptop cases with neoprene sleeves are okay if the main purpose of the laptop case is just to cover the laptop.

Those who travel a lot should opt for an actual hard-shell laptop case or a durable soft case with an extra pocket, handles and sufficient padding on the inside of the laptop for the safety of the laptop. A laptop is a delicate machine and has a high risk of getting damaged when transported. Those who travel a lot and have other products to carry along like binders, books or a scanner should invest in a laptop backpack with either shoulder straps or wheels attached to it. Another point to keep in mind when buying a laptop case is to buy a brand-name product, as these products have a longer life and are under guarantee against any production faults.

By Thomas Morva

Laptop Batteries

If you are among the increasing number of mobile executives who are switching from PCs to laptops, it is inevitable that you will soon face a situation where you will need to educate yourself about laptop batteries. And then, at some point, buy them.

Here are some basic guidelines:

Brief Background of Laptop Batteries:
The earliest type of battery used the chemicals Nickel Cadmium (NiCd, NiCad), and was very quick to charge and was also able to handle high loads. However, these chemicals are highly toxic. The next generation of batteries, the Nickel Metal Hydride (NiMh, NiMH) batteries, now use Nickel and other rare earth metals as its electrodes and Potassium Hydroxide as the electrolyte. These are more environmentally friendly than Nickel Metal Hydride, but suffer from the memory effect, and have a short lifespan. A newer type of battery is the Lithium Ion (LiIon, Li-Ion) powered battery. In spite of being smaller and lighter than NiCd and NiMH batteries, it provides the same capacity. Also, these batteries do not suffer from "memory effect" and have low levels of self-discharging.

The Lithium Polymer Ion Battery:
This is the latest type of battery chemistry. Though this behaves in the same way as Lithium Ion, there are some important differences. The Lithium Polymer Ion Battery uses a thin plastic-like film as the electrolyte, resulting in considerably reduced weight, and a greater power to weight ratio than most of the other types. They are used in Universal Laptop Batteries. So this is the type to look for, when you need a new battery for your laptop.

What are Universal Laptop Batteries?:
Most of the top manufacturers like Sony, Compaq, fujitsu, Toshiba, Panasonic, Dell, IBM, Lenovo Apple, HP, are providing the Lithium Ion battery technology. The Universal Laptop Batteries, however, use the more advanced Lithium Polymer Ion chemical A universal battery is just a larger version of the standard laptop battery, and can power virtually any laptop.

The universal batteries are rechargeable - the AC Adapter and power lead are provided by the manufacturer. Also, the manufacturer supplies a number of tips that fit the power supply connector on the laptop. These tips enable the smart electronics embedded in the battery to supply electricity at the correct voltage.

Another plus point in favor of universal laptop batteries is that the continuous usage time is up to 10 hours at a stretch. (Of course, there are variations according to manufacturer and model of the universal laptop battery.)

When do I need a new battery?:
You do not necessarily need a new battery only after the current one is completely used up. Some laptop manufacturers offer laptops with expansion slots that will accept a variety of peripherals, including a second battery. This second battery can double your battery life. But, if you are planning to get a lot of work done on that long flight, then it may be time for you to purchase a new laptop battery.

Remember:
When buying batteries, ensure that the supplier and the manufacturer are reputable. Be sure that the Supplier/Manufacturer offer full guarantee and warranty. Check the chemistry and dimensions of the universal laptop battery before purchase. And provide the supplier with all the information about your laptop such as the make, the model, the part number, the Voltage and Current ratings (provided in the manual or underside of the laptop) in order that the supplier can assist you with the most suitable battery.

By Samantha Spiegla