All Tech :: May

May 24, 2008

Bad Laptop Motherboard - To Repair Or Not To Repair

Filed under: Computer

To sit down in front of a laptop computer, a model you have never worked on before, and to attempt to figure out how you are going to dismantle it, and then put it all back together again, can be a little unsettling. This is the scenario I have faced many times when my diagnosis have led me to the fact that the laptop in question does indeed need a new motherboard. The motherboard going bad in a laptop is not an extremely unusual occurrence, but it is going to be one of the most expensive hardware repairs that a laptop owner can face.

I always recommend that the owner of the laptop stop and weigh out the options. Is the cost of the repair, (parts and labor), going to be more than a new, used or refurbished replacement laptop would cost? If the repair cost is less than the cost of a new laptop, how much less is it? Is the difference worth taking a chance on the old one? Maybe the laptop, with a new motherboard, will last for several more years. Maybe after the motherboard is replaced a stick of RAM or something else decides to go bad, and a sense of a money vacuum sets in. Ultimately it is up to the owner of the laptop to decide on how to proceed.

In my experience, if the laptop is not all that old and otherwise functions properly, then the cost of parts and labor is just a fact of life and would ultimately wind up being the most economical way to go. I do like to mention also that a new laptop will come with a warranty of usually at least a year. This helps put a stop to the potential money vacuum of repairs, but new laptops can have motherboards go bad also. Then there is the cost of time that it takes for the laptop to be repaired under warranty.

Parts going bad are just a fact of life. It happens in vehicles, home appliances, audio video equipment and computers. Laptops do not sit nice and stationary like a desktop computer does. Laptop cases are built to be quite sturdy from the outside. They are taken into many different environments and often tossed around slightly, but they are designed to be treated this way to a point. Although there are no moving mechanical parts in a laptop, other than fans and drives, the design of the circuitry on a motherboard is actually rather sensitive to heat and power fluctuations.

It is a good idea to keep laptop computers free of dust as much as possible. You should especially make it a point to keep the vent areas of the case that cover the laptop fans free of any form of dust or blockage. A vacuum or even a can of compressed air are adequate for keeping this area free of dust. Only use the proper rated power adapter for the laptop. Be weary of unstable power sources or plugging the laptop into an already over crowded power strip if possible. These simple tips will help to prolong the lifespan of your laptop computer.

Toby Barns is a computer and networking consultant with over ten years experience as an independent representative of many major computer manufactures and retailers. Toby has worked in tech support call centers, led teams of advanced technicians in the computer manufacturing industry, done consulting for retail computer outlets, and as a field representative for many major computer warranty service providers.

Toby is pleased to currently be part of the team at http://priceit.biz

Article Source: http://EzineArticles.com/?expert=Toby_Barns

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May 18, 2008

Network Time Synchronisation using GPS

Filed under: Gadget

by: Dave Evans

The GPS system is a global navigation and positioning system. It is most commonly known for providing navigation systems for cars and marine vehicles. However, the GPS system also has a less well-known feature - precision time. Each GPS satellite orbiting the Earth has onboard a high precision atomic clock. This clock can be used by NTP time servers and other computer network timing systems as a highly precise source of time. This article provides an insight into how the GPS system can be used to synchronise networks of computers and also discusses the equipment required to receive accurate time from the GPS system.

The GPS system is a United States military system intended for global navigation. The GPS system is a space-based system, consisting of a network of 24 orbiting satellites. Precise navigation and positioning is achieved by utilising precision timing signals and triangulation between multiple satellites. In order to provide very precise time, each satellite has an integrated highly accurate atomic clock onboard. Each satellite broadcasts timing information to within a few nanoseconds of the correct time to provide positioning to an accuracy of better than 10m. This precise timing information can be used by NTP time servers and other computer timing equipment as a highly accurate time reference. The great thing about GPS is that it works anywhere in the world and is entirely free to air service.

Each GPS satellite transmits a low-power radio signal down to the surface of the Earth. Two separate frequencies are utilised, designated L1 and L2. The L1 band is the civilian signal; transmitted at 1575.42 MHz. L2 is the military frequency, intended for ultra-high precision positioning. Broadcast radio signals travel through the air by line of sight. The transmitted signal is easily powerful enough to pass through clouds, glass and most plastics but is absorbed by more substantial material such as brick, roofing materials and metals. Ideally GPS antennas require a good unobscured view of the sky. Therefore, ideally the antenna should be located high-up with a good all-round view of the sky.

With the advent of GPS navigation equipment for the mass market, GPS antennas and receivers can be obtained at very reasonable cost. A GPS antenna is utilised to receive and amplify the GPS radio signals. While a GPS receiver decodes the information and presents it in a computer readable format. Many antennas are available with integrated receivers but these have the drawback of only providing a few meters of cabling to the host NTP time server or computer system. Marine antennas are designed to withstand the worst of the weather, they typically screw onto a threaded pole to provide a secure mounting system. These antennas provide the best solution for static timing applications.

The GPS receiver is generally embedded into the NTP time server or encapsulated within an enclosure. GPS receivers are small modules that have a connection to the GPS antenna to receive amplified GPS signals. The receiver decodes these signal and provides a computer readable output usually via a RS232 or USB interface. Most receivers provide decoded information such as: position, visible satellites, precise time and an accurate pulse output timing reference.

Coaxial cable is utilised to provide a connection between the GPS antenna and receiver. The cable distance can be critical. Any GPS antenna has to amplify received signals enough to overcome cable losses over the intended cable run. Better quality antennas generally provide more amplification (gain) additionally higher quality coax cables can be used with much smaller signal losses per meter allowing for relatively long cable runs between a antenna and receiver. For longer cable runs, an amplifier can be used to further amplify GPS signals to overcome cable losses. Typically, a GPS amplifier sits in-line on the coax cable and is powered from the receiver. Multiple amplifiers can be used for extremely long cable runs.

A roof mounted GPS antenna can be prone to lightning strikes and voltage surges. It is recommended that surge suppressors are utilised to protect expensive NTP time server and timing systems from potential damage. A surge suppressor is essentially a barrier that sits in-line on the coax cable between the antenna and receiver that protects the receiver from any potential damage due to voltage surges.

To summarise, the GPS system provides a highly precise timing reference for NTP time servers and other computer timing equipment. It is a reliable free to air service that can be used anywhere in the world. Additionally, with the boom in vehicle navigation systems the technology required to receive GPS broadcasts is continually falling in price.

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The author of this article, Dave Evans, provides a technical authoring service to a number of computer network timing hardware manufacturers. Dave’s expertise in the field of atomic clock, NTP server and time server systems has led to him becoming a leading author in the field. Click here, if you would like to read more about NTP time server solutions.

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