Network Interface Cards (NIC)

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A NIC (network interface card) is designed to communicate over a computer network. It allows users to connect to each other either by using cables or wirelessly if the NIC is a wireless NIC (WiFi / WNIC). Every entity on a network, a PC, printer, router, etc., that needs to communicate with other devices must have a NIC if it is to communicate over the network. On older computers, the NIC is probably an expansion card, usually PCI or PCI express. High performance cards can cost less that $ 30. NIC functionality is now often integrated into the motherboard chipset or implemented with a dedicated Ethernet chip on the motherboard.

A similar situation is true for laptop computers. At one time, a PCMCIA network card would be used in a laptop computer for the NIC just as the PCI card was used in desktop computer, but now, NIC functionality is often integrated with the motherboard.

Ethernet is the dominant standard for cable connections for wired computer networks. An Ethernet connector looks similar to a telephone connector, only larger. This connector is called "RJ45". Ethernet cables are either a shielded or unshielded cable of four twisted pairs of 24 AWG connectors, specified at 100 ohm impedance. Maximum cable length for CATX cables is 100 meters.

Early versions of Ethernet cables were CAT3 or CAT4 (CAT being short for category). These versions were not long lived. CAT5 and CAT5e are currently the most commonly used cables (bandwidth of 100 MHz, 100 Mbps), with CAT6 (bandwidth of 250 MHz, 1 Gbps) available and the configuration of the near-future. A CAT7 cable (bandwidth of 600 MHz) specification is in development, and should be available in a few years.

Each Ethernet NIC has a unique serial number called a "media access code" (MAC address) that is used to identify the NIC and associated computer on the network. No two NIC will have the same address, because the NIC manufacturers must purchase blocks of addresses from the Institute of Electrical and Electronics Engineers (IEEE).

NIC cards are capable of different speeds. Speeds of up to one gigabit per second (Gbps) are now available. Two NIC can communicate if they differ in speed ratings, but they will communicate at the rate of the slower NIC.

On a very simple network, NIC can be used to link personal computers (PC). If the computers are connected directly to one another, the network is a "peer-to-peer" (P2P, also called an "ad hoc") network. If computers are connected directly to one another, a "cross-over" Ethernet cable is needed (also called a "Null-Modem cable"). This cable is not "straight-through" like standard Ethernet, but crosses the send and receive connectors, so that send line from computer A connects to the receive line of computer B.

For networks of a few computers, a "hub" can be used, with all of the computers connected to the hub. Any message sent from any PC will be seen by all of the computers, but only the computer with the correct MAC address will receive the message. P2P networks are useful for many purposes. File and printer sharing are the most common applications.

Networks with more than four active computers at a time will benefit from using a "network switch" instead of a hub. A network switch will direct the message to the appropriate destination, instead of each message packet being broadcast across the network. Computer A can send a message to computer B, while simultaneously, computer C sends a message to computer D. This increases the efficiency of the network. This is a simple form of a server network. An example of a client-server design is a computer server where the clients initiate a download or upload of files and the server reacts. The server would also often be responsible for interacting with printers and other servers on other networks, including satellite networks (SATCOM) or the Internet.

"Latency" is the delay caused by a network to communicate data. Latency causes not only slow service, but can result in data loss as well. Latency is usually tested by sending a message packet that is immediately returned to the sending computer. The round-trip time is defined as the latency.

Networking performance can be optimized for either latency or throughput. Networks can use a technique known as "interrupt moderation" to increase throughput and lower CPU utilization by queuing message packets and issuing fewer interrupts to the CPU. A network optimized this way would favor large transfers, reducing transfer overhead. CPU and network throughput benefit, but network latency would increase. The alternative is to fragment each message and pipeline the fragments through the network. Multiple paths from source to destination can allow overlapping. Latency can also be addressed with techniques such as prefetching (anticipating the need for data requests) and / or using multiple execution threads (multithreading).

There are two indicator LEDs on a typical NIC. A single lit green LED indicates the computer is connected to the network. This is called the "link" light. The second LED is amber in color. A flashing amber LED indicates message packet collisions are occurring. Occasional collisions are normal on a busy network, but a frequently lit amber LED is an indication of problems. A quickly flashing link LED (green) is a network activity indicator, meaning that communication is occurring. If the green link light is off, and the amber LED is blinking, then the NIC is in "power save" mode.

A wireless network interface controller (WNIC) is a NIC for connecting to a wireless network (WiFi). The standard for WiFi is IEEE 802.11. A WNIC uses an antenna to communicate with an Rf signal, most often at 2.4 GHz. Wireless connectivity development in recent years has closely paralleled wired connectivity. Like its wired cousin, a wireless card was once integrated with a PCI or PCMCIA add-on card. Now, integrated WNIC's are becoming common, especially for laptop computers.

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Source by Brian Bradshaw

Why is Annual Maintenance Contract Important For Your Hardware-Software?

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Imagine a scenario where your laptop, motherboard of your PC, printer or even the keyboard develops a malfunction, then what will happen? Our dependence upon these gadgets is such at even a few minutes without them is unimaginable. What if your warranty period has exceeded the deadline of repair services? Worry not, wherever there is a problem, there lies a solution too. It is here that AMC (Annual Maintenance Contract) comes into picture. It is for your convenience that these services are provided by some well known names in the technical support industry, this service is also known as post warranty agreement which is devised to help you out of such situations.

If we think on terms of a situation where the motherboard of your PC is not working and it needs to be repaired or replaced then the market price would cost you a fortune, you would rather buy a new PC which would be relatively cheaper. But why not eliminate the problem itself instead of ignoring it?

For the purpose of annual maintenance opt for a company that offers reliable services, this would help save you time and money. How? The answer is quite simple, choose a company that offers its clients the best deals at competitive pricing, coverage of all computer hardware equipments and printers as well. The customer would enjoy the privilege of maintenance and repair of hardware throughout the year by just shelling out an annual fee. So, if you are offered to pay an annual maintenance charge that would be approximately equal to one time repair or replacement of your equipments then it would be more beneficial to you.

Though there are numerous providers of AMC but you must choose wisely, go for a company that offers benefits and advantages at the competitive level to its customers. Offering world-class services while maximizing client satisfaction should be the core area of ​​concern. Ensuring that customers receive prompt and cost effective services.

Choose to be associated with a well known name that sets a standard benchmark against which the maintenance services measure, watch out for testimonials by big clients who are providing the opportunity for maintenance of their own machines. Big names and renowned customers like, Toshiba , Lenovo, IBM, Acer, just a few names out of many such well known names in IT and Telecom. All this proves how highly the company providing AMC is regarded in terms of providing the best ever services in terms of hardware maintenance and post warranty services.

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Source by Ritu Kumari Sharma

Latest Technology in Computer Hardware

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The rate at which new computer hardware products are arriving in the market is simply mind-boggling. As the technology advances, the size and the price of the devices come down, while the efficiency and capacity increase. The scenario is same in all cases, whether it is about internal components like processor, motherboard, RAM, graphics card, and hard disk or for peripheral accessories like mouse, keyboard, and monitors. Personal computers became popular only before about three decades back. But already there are huge piles of outdated and antique hardware components and devices. This is a tribute to the tremendous rate of development of latest technologies in computer hardware field. Perhaps, the newest entrant into the archeological catalogue of computer peripherals is CRT monitors. The sleek looking LCD monitors are spreading like computer virus.

Data storage devices have attracted considerable attention of the technology developers. New kinds of storage devices such as newer versions of flash memory cards, hard disks using latest technology and disks of ever-increasing capacity are the results of advancement in latest technology in compute hardware. The memory size of the random access memory (RAM) cards is soaring to enable the smooth functioning of graphics animation software packages and streaming video websites. Also, computer motherboards have undergone substantial changes over the years. More and more functions are being added to the motherboard. Also, despite the incredible improvement in performance and functionalities, the price of these components has actually fallen steadily.

The most vital component of a computer is the microprocessor. It is in this field that a battle of developing latest technologies in computer hardware takes place. The pace of development of microprocessor increases as the competition between the major processor chip manufacturing companies, Intel and AMD, intensifies. Both the companies are engaging in a neck and neck competition and continuously outdo each other in introducing new technologies.

In the field of computer peripherals, the latest technology in computer hardware is in developing yet another version of wireless mouse and keyboard. The concept of wireless mouse and keyboard is about a decade old. But the development of these items is still a work in progress. The latest products of wireless mouse and keyboard are said to be highly durable and error free.

Some of the developments in the latest technology in computer hardware are gearing up for changing the present concept of desktop and laptop computers. With new developments making possible the convergence of mobile phone technology and computers, a new breed of fully functional palm-top computers are going to be introduced in near future. With touch screen monitors and without the need for a mouse, these gadgets are likely to become the next big leap in the constantly leaping technological development field.

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Source by Candis Reade

Stripping a Computer Tower for Precious Metal Refining

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When one decides to start in the exciting and lucrative world of computer and electronics recycling there are bound to be some mistakes. When I first started my company I made plenty of mistakes and they cost me a lot of money. However, after those mistakes I continued to adjust how I handled the materials and it has paid off in a big way.

The first thing that you should do is ensure that you have plenty of room to sort the materials because just about everything in a computer sells separately and to different sources in most cases.

So let's run down how to strip a computer for maximum value.

Step 1: Gain access to the inside of the computer tower. In my experience each tower is different. Getting inside can be as simple as removing a couple screws and sliding off the panel and can be as complicated finding the locking mechanism and pulling apart the case. There are some great internet sites that show the different methods for opening computers that can be found with a simple Google search.

Step 2: At this point I like to remove the power supply as it will get the wires out of the way. In most cases the power supply is screwed to the outside of the case with either 2 or 4 screws. Once those are removed the supply comes loose. From there simply unplug the various wires from the boards and drives and then set the power supply aside for disassembly.

Step 3: Now I like to remove the ribbon wires. These are the flat wires that connect the motherboard to the various components. These will usually pop right off. I then put them into a box or barrel and save them with other wires that will go into the local scrap metal yard.

Step 4: Now it is time to remove the drives. This can be a little tricky with some towers. Each tower is different as to how the drives are installed. Some can be as easy as compressing a couple of tabs and then sliding the drives out while others have screws that need to be removed. Once the drives are out of the case I set them aside for disassembly later.

Step 5: Removing the slot cards is next. These are usually controllers for devices such as video and sound cards as well as modems. They are attached with a screw at the top and then plugged into the motherboard. After the screw is removed they will pop right out. I then throw them into a box slated for sale to a refiner.

Step 6: Now it is time to remove the motherboard. Again there is no one way that they are attached. However, most of the time they are attached with screws and once they are removed the board will come right out. But, there are also some companies that use tabs that means that the board needs to be slid to one side before removal.

Step 7: With the motherboard out you can remove the ram sticks. These pop out by pushing down the tabs on each end. Once out they should be put into a box and collected for sale to a refiner.

Step 8: The last thing is to remove the heat sink, fan and then the processor. The heat sink and fan are likely held on with a lever that can be easily lifted off. Most heat sinks are aluminum and can be collected and then sold to the local scrap metal yard.

Step 9: Removing the processor is a simple case of pulling up the arm on the side that unlocks the pins and the processor can be pulled out. I toss the processors into yet another box where they are collected for sale to a refiner.

Now on to the other items.

Power Supply Disassembly: The power supply is a fairly simple unit to tear down. There are usually some screws holding the steel case together and once removed the case will come apart. Then there will be some screws holding the circuit board to the lower part of the case. Remove those and then toss the case into a box that will be taken to the scrap metal yard.

On the power supply are many wires that should be cut off. A simple pair of wire cutters can be used to clip off the wires which will then be tossed into the box or barrel where you put the ribbon wire.

The board is what is known as a "low grade brown" circuit board. These are actually pretty low on value and I collect mine and sell them to the local scrap metal yard for about.50 per pound and it adds up fast.

CD / DVD / Floppy Drive Disassembly: Disassembling CD or Floppy drives is fairly simple. Just look for the screws that are holding the cases together and remove them. Once you have access to the inside you need only remove the boards and the cases can be tossed into the scrap steel bin.

The boards from the CD / DVD / Floppy drives are considered mid-grade boards. They have moderate precious metal content. I place them all into the same box and then sell them to my refiner for $ 1.00 per pound.

Hard Drive Disassembly: Hard drives are a bit more valuable in the grand scheme of things. However, they are also more difficult to disassemble as well. Most hard drives are held together with star screws. On the front cover remove all the screws that you can see. Under the label there is going to be at least one more screw if not two. Once you have the screws out the top will pop off. This is aluminum and should be placed in your aluminum box.

Once you have access to the inside you will see the round, silver discs that hold the information for the hard drive and an arm that is resting on them. You will need to remove the screws around the collar holding the discs down. Then you will remove the brackets holding the arm on. They are held on with screws and two magnets that are made of rare earth materials.

The magnets can be saved in another box and sold online for a decent price. The discs should be collected and sold separately as they have a layer of platinum on them.

Once these items are removed you will need to turn the base over and remove the circuit board. These are known as hard drive logic boards and they are valued at $ 9.00 per pound and up. They should be saved and then sold to a refiner.

The base is made of cast aluminum and can be tossed into the box with the other materials.

This completes tearing down a computer tower for refining. You have several options for selling materials. eBay is a resource that a lot of e-cyclers like to use for selling their materials but there are other options.

A bit of warning: Never sell to the websites that say that they are buying for gold refining and offering to pay for the shipping with a pre-printed label that they will send to you through email.

I decided to do a small experiment. I collected two boxes of motherboards and listed one on eBay and sent the other to one of those places online. About a week later I had a check from the website for $ 7.50 for 25 pounds of motherboards and a PayPal payment from a buyer on eBay for $ 600 for 25 pounds of motherboards.

I found a refiner that operates in Ohio that I send all of my gold bearing material too. They pay some great prices and it makes things a lot easier. It also saves on the eBay and PayPal fees that have become quite high over the years.

The other materials, such as low grade brown boards, wires, aluminum and steel I just transport to the scrap metal yard. Collected over a period of time these items can really add up to some serious cash. For me it makes a great way to keep my gas tank full for picking up more computers from my various clients.

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Source by Craig E Weaver

Xbox 360 Freezing Is Caused By A Loose GPU! Learn To Repair Xbox 360 Freezing!

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Xbox 360 freezing is a very common problem. In fact, close to 1 million people are dealing with Xbox 360 freezing. In an official Microsoft announcement in July 2007, Microsoft admitted that 5% of all consoles sold are failing and the rest have a chance of failure.

If you would like some help with Xbox 360 freezing, and would like to repair your Xbox 360 once and for all, this article is for you.

The cause of Xbox 360 freezing

Your green lights will turn into 3 red lights that begin flashing when your GPU (graphics processing unit) comes loose. The GPU (which is on the motherboard) comes loose as the motherboard heats up. As the motherboard heats up it begins to vibrate. These vibrations loosen the soldering holding the GPU in place, and every time it comes loose you get your Xbox 360 freezing up.

This article will help you with Xbox 360 overheating and freezing, but before you do anything, know this: the towel fix you may have read about is bogus. It will damage your Xbox 360 and make the problem worse. 94% of red light error Xbox 360s do not need new parts, just a little tweak to fix them.

If you use the "towel" fix, you risk permanent damage and you may no longer be able to repair your Xbox 360 freezing on your own (you will need to send it in for repairs). You have been warned.

How To Fix Xbox 360 Freezing Up

Before we being, I suggest you see a professional Xbox 360 repair guide with videos and picture. A professional Xbox 360 freezing repair guide will show you everything step by step, which can really help you through this process.

Here is how to fix Xbox 360 freezing:

1. Take your case apart. Using a fine tip poker, poke the grayed out holes (they are the latches holding it together) and at the back poke the tiny rectangle holes. Take the faceplate off and move the latch up on the DVD drive up as you remove it. Unscrew the metal case that is just under the plastic case.

2. Take the DVD drive out and unplug the cables.

3. Take the fan off and the motherboard out.

4. Flip the motherboard over, and, using the poker, pry off the X-clamp under the heat sink by popping up the corners. The heat sink is the big silver box with slits in it.

5. Unscrew the heat sink to reveal the CPU and GPU.

6. Clean the GPU and CPU (critical step to stopping Xbox 360 freezing)

7. Apply arctic silver thermal compound (you can find a $ 1 tube of this at any computer store) generously over the GPU.

8. Let it set for 15 minutes.

9. Put 2 nylon washers on each of the screws from the heat sink. Put the screws back in the motherboard. Now, with the screws pushing up through the motherboard, add 2 more nylon washers to the screws.

10. Put the heat sink on top of the screws, pushing them down a little, then screw them up. Make sure they are tight. This is will really help with Xbox 360 freezing.

11. Put everything back together. Turn it on.

There, you should now have fixed your Xbox 360 freezing.

If you need help with pictures or videos, again, I suggest you check out an Xbox 360 freezing repair guide.

Xbox 360 freezing repair guides are fairly cheap, around $ 25, and they save you over $ 100 from sending it Microsoft into. Plus, Xbox 360 freezing repair can take up to 6 weeks if you send it in.

Whatever you do, do not do nothing. Xbox 360 freezing will not go away on it's own. Once you get Xbox 360 freezing, you will keep getting the 3 flashing red lights until you fix your system.

Best of luck fixing your Xbox 360 freezing problem!

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Source by Anthony Uccello

The Importance of Upgrading Your Computer System

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If you want to have a computer of your own, then you must understand one thing about them. You see, computers are not things you must dispose of after a number of years. It is something you can build on, improve and upgrade. A computer can last you a very long time. If there is one thing you need to know about computers it is that the only thing it needs for longevity is an upgrade. You should not be afraid to upgrade your system. Doubt is something that's common with inexperienced computer users. But if you want to have a better system, one that lasts you a very long time, you have to open up to computer system upgrades. Here are a few upgrade suggestions depending on your needs.

If you start to notice a slowing of your systems, then you might need an internal hardware upgrade. A simpler approach would be to reformat your computer, but sometimes, that just will not do. When it comes to computer speed, the key components are the memory and processor. Memory is very easy to upgrade. All you have to do is buys new memory chips and put them in the empty memory slots in your computer. The processor is a bit harder to change, though. First, you have to make sure the new processor you want is compatible with your current motherboard. If it is not then you can either look for another processor that's compliant, or replace your motherboard with something that's compatible with it.

Another upgrade you might want to do is shift to a dual monitor system. A dual monitor system is great for people who need to monitor many tasks at one time. This is also great for enhancing the gaming experience. If you want to shift to a dual monitor system, just invest on two LCD or LED monitors and ensure your video card can handle the dual monitor system. You can also invest on a dual monitor stand which saves you a whole lot of space even with two monitors on your desktop.

Upgrades are necessary to lengthen your computer's life, and once you understand how you can easily upgrade your computer, you will enjoy a faster and more responsive PC without spending too much money on purchasing a new system.

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Source by Sam Lee

Xbox 360 Fixes to Avoid

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Does your Xbox 360 have the RROD, E74, or some other common error? Are you confused about which Xbox 360 fix is ​​right for you?

Many owners are overwhelmed with the number of possible Xbox 360 fixes available to them all over the Internet.

Most people are out to find the quickest fix possible, but you need to be sure to watch out for those so called "quick fixes". Some of those quick fixes include the towel trick, which involves wrapping your Xbox 360 in a towel, and the toothpick / paperclip trick, which involves stopping the fans with toothpicks or paperclips. The towel, toothpick, and paperclip trick are three very well known Xbox 360 fixes, and are found all over YouTube. Both so-called fixes are harmful to your system, and I would strongly recommend that you stay away from them. These fixes over-heat the entire system, instead of just targeting the problem areas, causing more problems than you even had before.

Both of the tricks I mentioned previously will give you a working Xbox 360 for about a week max. That is, if you do not damage the system during the process. The towel and the toothpick trick both are designed to heat up your Xbox 360 so that the solder of the GPU chip can reattach to the mother board. The GPU is a computer chip that is almost always responsible for causing the Red Rings of Death (RROD). Now most of the time you can somewhat reattach the GPU to the motherboard with the towel or toothpick trick, but there are two major problems / risks. The first problem is that the system by itself does not generate enough heat to fully reattach the GPU to the motherboard. Another risk is that the motherboard is not properly insulated. Without the motherboard being properly insulated, you run the risk of damaging other components of the mother board. The Xbox 360 motherboard can never be properly insulated unless you take your console apart. If a fix does not involve opening your console, it is most likely not going to work, or it will last for a very short period of time.

So, if your warranty is up and you are determined to fix your Xbox 360 by yourself, stay away from the towel trick, the tooth pick trick, and any other so called quick fix that does not require you to open up your console.

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Source by Jordan S Scheller

DC Regulated Power Supply – How To Use It To Find Out Shorted Components In Main Board

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Quite often whenever electronic equipment do not function or work, we would immediately suspect a faulty switch mode power supply. But do you know that defective or shorted components in the motherboard or main board could cause the power supply to stop working too?

Switch mode power supply (SMPS) are designed so efficiently that whenever there is any short circuit occur in the main board the power supply would shut itself off and totally stop working. If you have no experience about troubleshooting switch mode power supply, you may think that the power supply have problem where in fact the main board is the real cause of no power problem.

Switch mode power supply have a current sense circuit (if you look at UC3842 PWM IC pin 3, it stated I-sense which mean current sense) and if there is short circuit in the secondary side (either in secondary diodes or main board), the current drawn would be increase and this will lead the PWM IC to stop generating output to the power fet and thus the power supply would shut down. All this happen in a split of seconds and you do not have the chance to know if there are output voltages at the secondary side.

Some older design of SMPS power supply do not use the PWM IC, but it do have the circuit to detect over current drawn and shut itself down whenever it detects a shorted component in the secondary side. One good example was the power supply used in printer. Printers usually have two boards; one was the power supply while the other was main board. If there is any short circuit in the main board, the power supply would not work. In order to isolate at where the problem is, one must remove the connector from the power supply board. Once the supply connector to the main board was removed, you can now switch on the printer and check if there is any voltages present at the power supply connector.

If there are zero voltages measured across all the supply (VCC) pins then we can conclude that the power supply have problem and you can put your whole concentration in this power supply board. What if there are voltages measured across the connector? This means that the main board is causing the no power problem most probably due to some shorted components in the main board.

For your information, dot-matrix printers usually required two voltages to function. One is the 5 Volts (for logic IC, eeprom and CPU) and the other is 30+ volts for the motors. The question now is how do we know if the main board is the main cause that shutting down the power supply? Very simple, just use your analog multimeter set to X 1 Ohm and measure between the supply pin (say 5 volts pin) and the main board ground and then reverse the probes. A good board should not show two similar reading and if you get two similar ohms reading then this means that the 5 volts line had shorted to ground through some faulty components.

If you have confirmed that the 5 volts line have problem then how do we find out the culprit since there are so many components connected to this line? TTL IC's, CPU, EEPROM, transistors, diodes and even small filter capacitors are all connected to the 5 volts line. Either one of these components shorted could cause no power to the printer. You may remove each components lead (5 volt supply) in the main board and hope that the short circuit will be gone. Assuming if you happen to remove one of the filter capacitor pin and the short circuit is gone then we can say that the real culprit is the filter capacitor.

The real problem is what if the board has many components on it and this will consume lots of your time to isolate the problem by removing one pin at a time. It is not easy to identify the supply 5 volts pin to a spider IC that has 100 pins or more. Many spider IC's have more than one 5 volts supply pin. Some even have 4 and some have 6 to 8 supply pins. Does this mean you have to check one pin at a time until you finally locate the fault? Not only that, to remove the supply pin from the spider IC's and check for any short circuit between the grounds required a very good skill too. If you messed out the circuit board track, the main board can then be considered beyond repair. Even though you can repair the broken circuit track, this does not mean you have solved the actual fault!

Do you see the extra problem arise when you try to find out the fault? There must be some better way to tackle this kind of problem. Yes it is true that one can use ESR meter to slowly track to the source of the short circuit You can utilize the ESR meter to locate short-circuits on electronic boards by checking the actual track resistance. One probe connects to the ground and the other to the circuit line and if the measurement rises as you probe further along the track, you know that you are heading to the wrong direction! If the ESR value decreases as you move along the track then you are in the right direction. The problem is what if the main board has double layers, 4 or even 8 layers? You may be wasting lots of your precious time trying to track to the actual fault using the ESR meter method! After explaining so much about the problems, now is the time that you are waiting for to get the answer on how to solve this kind of fault fast.

Do you know that the DC regulated power supply besides using it to power up electronic circuit it can also be use to troubleshoot and find out a shorted component in a motherboard? Assuming you have confirmed that the VCC supply lines shorted to ground through some faulty components, you can easily detect it with the use of a variable digital DC regulated power supply. If you do not have the digital one you can always use one with the analog panel meter which is cheaper.

Now connect the alligator clip from the positive output supply to the 5 volts VCC pin in the main board and the negative output to the main board ground as shown from the picture. Once everything was done, it's time to switch on the dc regulated power supply. Slowly vary the knob clockwise and see the voltage increase. At the same time the current draw can be seen from the current digital meter readout. From experienced, if there is a short circuit in the main board, whenever the voltage is increase, the current will rise dramatically and if no short circuit there would be less current draw.

Okay back to this problem, if you observe that the current drawn also increase (rapidly) as proportion to the rise in voltage setting, you are now for sure that there is component shorted in the main board. What does this mean? It is a good news to us, because if the current drawn too much we can know the culprit by touching on the hottest components in the main board. Using your finger you can touch on any components that are very hot. Touch on the IC's, diodes, transistors, capacitors and etc. Once you located that only one component that is extremely hot to touch then that was the culprit! That's the real cause that you are trying to find! I've used this method to solved lots of main board problem and usually the culprit turned out to be a defective gate array and ram IC.

Why do not I immediately turn the output voltage from the dc regulated power supply to 5 volts since the defective main board is also using 5 volts to run? If I do this and if the faulty components turned hot too fast, I'm afraid this will lead the faulty component to open circuit. If the faulty component open circuit, the current draw will drop and the only clue that you have to identify the culprit has been destroyed! If this thing happens then you may not have a higher rate to repair the board. Of course you still can by replacing one by one the SMD spider IC's but this will surely eat up lots of your repair time.

The above method I've just mentioned is not limited only to printer main board; it can apply to other type of board as well like the computer motherboard, hard disk, dvd, vcd, industrial board and etc. Get a DC regulated power supply and I'm sure you can detect shorted component in the main board in the shortest time possible! By the way the specification of the DC regulated power supply that I'm using was 5A 30 volts (variable type). Have a good day my friend!

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Source by Jestine Yong

Diagnosing And Troubleshooting Computer Hardware

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What is Hardware?

Are these terms familiar to you? Monitor, RAM, CD drive, CPU, graphic cards are all hardware, or more accurately, computer hardware. These components make up a computer, working together with computer software to make a computer work.

Simply put, hardware is the tangible parts of your computer, parts you can touch, feel and so on.

Hardware Failures

As mentioned before, hardware and software work together to form a fully functional system, theoretically. However, rarely do you get a fully functional system all the time. There will almost certainly be malfunction of hardware, be it within the electronic circuits or even the whole component itself. Sometimes, the originating factor of the hardware failure is not the components of the system itself, but due to outside factors such as environmental disasters like fire, earthquakes and lightning storm.

Recovery of failed hardware components is not a big problem by itself. It is basically identifying and replacing the problematic component. However, hardware failures are most deadly, when it affects daily routine and affecting critical personal or business data. This is especially true of the most important component of a computer system when it comes to storage of data, the hard disk.

The following is a list of common hardware failures:

  • RAM Failures
  • Power Connector
  • Hard Disk
  • Overheating
  • LCD Failures
  • Motherboard
  • USB Box

RAM Failures

Bad RAM is somehow harder to diagnose as similar symptoms may be caused by software problems, other hardware problems or even motherboard failure. However if you experience any of these symptoms, users should check for bad RAM before attempting any other troubleshooting.

Symptoms:

  • Windows does not start showing different error messages each time.
  • Windows crashes (blue screen) or freezes frequently.
  • Windows crashes as soon as you try to start a program.
  • Unexplained random crashes and freezes without error messages.

Power Adaptor

The common weak spot on any laptop is the DC power jack. If someone trips over the power adapter cable while it is still connected to the laptop, there is a high possibility that the power jack will get severely damaged.

On most laptops, the DC power jack is soldered directly to the motherboard and there are only three or four small pins holding it in place, which makes the power jack rather weak. Any sideways pulling of the DC power cord while attached to the laptop will usually dislodge at least one of these pins, breaking the solder around it. Modern laptops use quite a lot of power, from about 70W to 120W or even more. The bad electrical connection from the dislodged pin will cause sparks and heating that will eventually burn a hole through the motherboard and can even be a fire hazard.

Symptoms which indicates poor contact between the DC power jack and the motherboard:

  • The battery is not charging properly or stays at half charge despite having to use the power adaptor.
  • The screen flickers (the brightness is changing) while the power cord is plugged in. This is caused by the laptop switching between DC power (screen is brighter) and battery power (screen is dimmer).
  • The DC plug gets hot after a few minutes of use and may even smell of burning.
  • There are "scratching" sounds coming from the DC jack.

How to test for broken power jack:

    1. Remove the battery 2. Plug in the power cord 3. Start the laptop 4. Gently wiggle the DC power plug on the back of the laptop

If the laptop shuts down abruptly (looses power), find the dealer to re-solder or change the DC power jack as soon as possible as the motherboard has already started to burn around the dislodged pins. The manufacturer might offer to replace the whole motherboard; however the price of a new motherboard together with the labor charge for installing it will usually cost more than the current value of that laptop and sometimes can the pricing can cost over a thousand dollars.

Replacing or re-soldering the DC power jack is not an easy job. It usually takes a few hours depending on the damage and the model of the laptop. To reach the power jack, the laptop has to be completely disassembled and have the motherboard taken out. Then if the board around the dislodged pin is badly burned, the power jack has to be un-soldered and the board has to be patched.

After that a different power jack has to be installed, attached to the case of the laptop and connected with wires to the motherboard, as the patched board would not be strong enough to support the original type of power jack that was soldered directly to the board.

Hard Disk

Hard disk failures are the most common computer hardware problems. And laptop hard disks fail more often than desktop hard disks due to the portability of a laptop as compared to the rather stagnant laptop. If user knock hard or drop the laptop even a few inches while the hard disk is being accessed or powered up, damage can be done to the hard disk.

Symptoms:

  • The laptop starts as usual but when Windows starts to load it goes to blue screen with either "UNMOUNTABLE_BOOT_VOLUME", "hal.dll is missing or corrupt" or "WINDOWSSYSTEM32CONFIGSYSTEM" (or similar) is missing or corrupt. All these error messages indicate a file system problem. Sometimes it can be fixed by just scanning the hard disk for errors. However more than half of these cases indicate that the hard disk is starting to go bad and is probably developing bad sectors.
  • The laptop starts as usual but Windows freezes on the initial "Windows XP" screen, although the blue bar continues to move, and users are able to hear feint but continuous clicking. Hard disks have to be replaced.
  • As soon as the laptop is started there are loud clicks or grinding sounds and Windows does not load. Hard disks have to be replaced as well.
  • Shortly after starting the laptop a message appears (usually on a black screen) "SMART test failed. Backup your data immediately and replace the hard disk" or similar. Well, that says it all. SMART is a self-test that is build into the hard disk.

In almost all cases the laptop can be started from a "live" bootable CD and everything works normal. In rare cases the hard disk PCB (printed circuit board) may get short circuited and even burn. In this scenario, the laptop will not start unless the hard disk is removed.

Good tool to A to use lands check for hard disk lifespan is ADRC's hard disk checker . It will scan the hard disk for bad sectors and inform you if the drive is still of good usability.

Overheating

Overheating happens when inadequate airflow from outside the computer's case across the CPU and motherboard and back out of the case usually via the power supply fan and other case fans.

Once the airflow is disrupted, heat builds up rapidly within the case. This causes components to either shutdown, if such protection is built in or performs erratically. Over the long term, overheating can irreversible damage components.

It is also advisable to keep the computer in a dry and shaded room, which is clean and little dust.

LCD Failures

The most common LCD or "Liquid Crystal Display" screen failure is the inverter, cable and backlight.

Symptoms:

  • The laptop appears to start as usual but the screen is black, if users move it, it turns on and works properly. Failed cable.
  • The laptop appears to start as usual but the screen is very dark, although it changes colour a little and users can see a very feint image. Failed inverter or cable 90% / 10%.
  • Immediately after starting the screen has dark pink / red tint and turns dark after a few seconds. Failed backlight.
  • The screen flickers a few times but then turns dark, if users move it or tap it lightly on the sides, it flickers again. Failed cable or LCD 50% / 50%.
  • Screen is either black or white (no picture) and external monitor works. Failed cable or LCD 30% / 70%.
  • There are stripes on the screen (either vertical or horizontal) that change when users move the screen or tap it lightly on the sides. Failed cable or LCD 10% / 90%.

Motherboard

Most motherboard related failures are due to the "On-board" regulated supplies and component failure within those circuits. The on-board power supply circuit had partially failed and was overloading subsequent components else the problem would be with the capacitors which are defective in the first place.

A motherboard failure on a laptop that is out of warranty would usually mean that it's time for a new laptop. The price of a new motherboard is usually higher than the current value of the laptop.

Symptoms:

Plug in the power adaptor and try to start the laptop.

  • Nothing happens.
  • The "ON" light comes on, the fan spins, but nothing on the screen (black) and you can not hear the HD working after 10-15 sec.
  • The "ON" light comes on, the fan spins, but after a few seconds the light goes off.
  • After pressing the "ON" button the screen stays black and you can hear a quiet high-pitched sound coming from the laptop.

Corrupted or improper device drivers and operating system

Invalid or corrupt device drivers can wreck havoc on a server, rendering the system unbootable in some cases. Device drivers may also conflict with certain application programs and cause problems with the computer system.

As Windows Vista has just made its launch, chances are some hardware is not supported or not supported fully by the new operating system.

Also, system updates, driver updates can also fix your "hardware" problems.

See updating and fixes

Also, it helps (occasionally) to call the respective support service for help on the driver that is with that particular hardware.

Controller Failure:

A controller failure can act much like a drive failure. However, when a drive fails, users can not access that particular drive; when a controller fails, users can not get access to all the drives, devices and any other components that is attached to that particular controller.

A controller fails because a component or components on the on the controller board fails. When users trying to boot the system, they can not switch on, view, access, or even get hardware conflict messages.

Controller failure occurs due to one of the following reasons:

  • Devices / components not connected properly
      Verify that the cables are properly connecting the device / component to the controller
      If the component fits into a slot, see that the it is flushed in and not loosely connected.
  • Devices / components not setup properly
      Verify that the devices / components is being properly detected and setup in the respective controller setup screen
  • Bad connectors
      Replace the bad connectors with new working ones
  • Bad components
      Replace the component
  • Bad interface board or motherboard
      It is recommended that these components be replaced or that the computer be sent in for servicing

Hardware Failure: The big issue

The big problem, as mentioned earlier, is not replacing or repairing the non-functional hardware, but the time lost, interruptions to daily routine (especially for businesses), and the loss of critical data. If you need a running system at all times, have a backup system as a fail safe, or even two. If users want to ensure that none of their critical data is lost in the event of a hardware problem with their computer, there is only one way to do it – Back up the data as often as possible.

There are many different ways to ensure that the data is backed up, and as technology becomes advances, back up methods become much simpler.

Let's look for a moment at what a back up is. Backing up of computer files means that users are making a copy of the data that will be stored somewhere other than on the computer. Everyone should always have a back up of at least the most important files, because should anyone experience a hardware problem, they could still be able to access the files.

Many people do not back up their files, because they do not know what they need to back up. Start with those files that can not easily be recreated. Then, move on to files to which you make frequent changes just in case you accidentally change something that you should not have. Back up your music collection – because this can be quite expensive to replace in the event of data loss.

In general, best practice is to back up the files at least monthly and more frequently if users access the files regularly.

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Source by Ning Chee

The Role of a Good Cooling Fan for Computers and Electronics

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What the Fan Does

The main job of a computer or electronics fan is to keep the part cool. Chips inside them can get very hot so air flow keeps them at a regular temperature. Sadly, stock fans within electronics sometimes are not enough. Especially if there are several components working together, perhaps in an office or entertainment center.

That's why a good fan and fan filter are a great addition to any setup. Learn more about the various types of fans below.

Common Types of Fans:

• Power Supply – Most power supply units or PSU's are provided with a 90mm or 120mm fan filter and internal fan.However, some suggest that they have two fans, one for intake and one for out-take. It is very crucial to keep all elements cool to lengthen the life of the equipment. Avoid melting and even exploding components from overheating by providing this type of cooling. The absence of a fan can greatly reduce its life span. Why take a chance?

• Central Processing Unit – Having a smoothly operating fan in this unit is a critical step to have a computer or other device that performs well. Newer CPUs will have an internal temperature between 35 and 74 degrees Celsius, which is why a constant airflow from a fan and 120mm fan filter is necessary. The heat will continue to move off of the heat sink as required.

One can bet that if the CPU gets over 80 degrees Celsius it will fail in some way. A damaged motherboard means it's time to buy a new unit in most cases.

• Graphic Processing Unit – This type of fan is almost always found on high end video cards. It's similar to the CPU fan in most ways, and helps keep games working smoothly with minimal issues.

• Chipset – Chipsets in the motherboard come with both built in fans and 120mm fan filters and passive heat set ups. Many prefer passive heat but even these tiny fans work hard to keep things cool and cooperative. All elements, big or small need to stay operative and cool.

• Case Fans – Also known as chassis fans, not every system or setup needs a case fan, or comes with one. No one should ever rely on the system to cool itself, it's ineffective. Case fans come in many sizes as mentioned before; the most popular size is the fan and 120mm fan filter. Check the least in and outtake to see a huge difference in the effectiveness of any setup. Keeping the room temperature less than that inside the computer or part makes a huge difference.

Doing research is the best way to decide the final set up for what components are owned. There are many other fans that are wonderful supplements, and that can be installed. These include hard drive, PCI slot, and CD style. These types are great for helping CPU's and video cards run at maximum efficiency.

These fans are almost always considered more of an option, while the above-mentioned fans are more mandatory. However, rest assured they do make a difference. Individuals can find fans and 120 mm fan filters from local and online sources.

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Source by Johny Brown