วันพฤหัสบดีที่ 4 ธันวาคม พ.ศ. 2551

Testing Diode -The Accurate Way on How to Test Semiconductor Diode Using Multimeter

Testing diodes is different from testing a resistor because you need a skill to do it. If you do not know or wrongly test a diode you will be unable to repair the equipment. A bad diode you think it is good. This will definitely waste your precious time.

A rectifier diode can fail in one of the four ways. It can become:

-Open
-Shorted
-Leaky
-Breakdown when in full operating voltage

An analog multimeter or digital multimeter can be used to check for all the first three conditions except the last one where the diode breakdown in full operating voltage. From my of experienced in the electronic repairing line, i found that checking diode using analog multimeter is more accurate than using a digital multimeter. I could explain to you why i preferred analog meter. I do not know about you because i really came across quite a number of diodes where it checked ok using digital multimeter but failed when test with analog meter.

The first step on how to test a diode is to remove one of the diode lead. You can't always be certain if a diode is good or bad if you perform in-circuit test, because of back circuits through other components. To be absolutely sure, you will need to lift, or disconnect, one diode lead from the circuit to avoid back circuits. Unless you are very sure about the board you are checking. Sometimes i do found bad diodes when checking it on board. Your experienced will tell you when to check a diode on-board or off-board. If you are new to electronic repair, i highly recommend that you check a diode with a lead removed from the board.

I will set my analog meter to x1 ohms to check for current diode leakage reverse and forward testing. Connecting the black probe of your meter to the cathode and red probe to the anode, the diode is reverse biased and should look like an open reading. Connecting the red probe of your meter to the cathode and black probe to the anode, the diode is forward biased and the meter should read some value of resistance. If you have two readings then most probably the diode is shorted or leaky and you should replace it. If you don't get any reading either forward or reverse bias, the diode is considered open.

The real problem when checking a diode using the diode test function of a digital meter is that an open or leaky diode, the meter sometimes reads ok(0.6). This is due to digital meter diode test output voltage (which you can measure the output test probe using another meter) is around 500mv to 2v. An analog meter set to x1 ohms have output about 3V(remember the two 1.5V battery you installed in the meter!). The 3V voltage is enough to show you the accurate reading of a diode when under test.

Even if you have a good reading at x1 ohms doesn't mean that the diode is good . You now have to set your meter to x10K to test the diode again. The output voltage of x10k ohms is about 12V(remember the 9v battery in your meter-1.5v+1.5v+9v=12v). Again the diode under test should show only one reading. This is exception to Schottky diode where it have two readings but not shorted reading. If the meter showed one reading then the diode under test is good. If it has two readings then most probably the diode is either shorted or leaky. The digital meter can't test it because the output from the meter is only 500mv to 2V.

If a diode breakdown when under full operating voltage, there is no way to testing diode (unless you have a very expensive diode checker which specially designed to locate this type of problem).Substituting with a known good diode is often the only way to prove that an intermittent diode is causing a particular problem. Sometimes an intermittent diode could be locate using a coolant spray.

Caution: Be certain that power is removed from any circuit before performing any of the following diode checks, otherwise meter or circuit damage could result.

Conclusion-In order to correctly test diode function you need to set the analog meter to x1 ohms and x10K ohms range.

Jestine Yong is a electronic repairer and a writer. For more electronic repair information please visit his website at <a target="_new" href="http://www.noahtec.com/electronic-repair-articles.htm">http://www.noahtec.com/electronic-repair-articles.htm</a>

วันพุธที่ 3 ธันวาคม พ.ศ. 2551

What Tablet PCs Can Do for You

Tablet PCs are great. If you are a mobile person, and you have never considered getting a tablet PC in the past, now is as good a time as any to start checking them out - the technology is cutting-edge, the usability is superb, and prices are starting to drop.

There are two main types of tablet PCs: convertible and slate. Convertible tablets look a lot like normal laptops except the screen can be rotated all the way around and laid down flat across the keyboard. You then input information through the screen using a stylus. Slate tablet PCs include only the screen interface ? though they are fully integratable with peripherals like keyboards and mouses, the computer itself does not have them. Both types are viable options, depending on your personal preferences and what you'll be using it for.

As with any technology, tablet PCs have advantages and disadvantages. Thanks to the last few years of development and enhancement, the disadvantages are shrinking in number, and the perks are becoming more and more enticing.

<h3>Advantages of Tablet PCs</h3>

Far and away, the best thing about tablet PCs is their mobility. You can take and use them anywhere you go, the same way you would take notebook and pen. That means that when your boss bumps into you in the hallway and gives you a number of assignments, you can write them down. In meetings you don't have to hide your face behind the monitor of your laptop because you can lay the tablet PC flat on the table. For students, this mobility is great - you can study your notes while you're waiting in lines or even in the car.

Tablet PCs let you use digital ink to store handwritten notes, graphs, charts, and pictures. You don't have to worry about taking your laptop and a notepad and pen to meetings or classes. Using the stylus, tablet PCs record your handwriting and drawings. They can convert your handwriting to text if you need to turn in an assignment typewritten.

All of the money you have been spending on pens, pencils, highlighters, notepads, papers, binders, folders, staples, and paperclips stays in your pocket. Because of the digital ink option on tablet PCs, much of the need for paper supplies and writing utensils is eliminated. You can keep all your notes on your computer.

Finally, one of the advantages of tablet PCs over regular laptops is that you don't lose any functionality from your computer. Tablets operate on similar platforms and run many of the same programs. In fact, many programs integrate all of their normal functions with digital ink, so you can add notes to documents and even email your handwritten notes to someone.

<h3>Disadvantages of Tablet PCs</h3>

Despite my obvious zeal for tablet PCs, I recognize that there are still some disadvantages. First is the price. The prices for tablet PCs are coming down quite a bit from when they were first released, but on average, you can expect to spend more for a tablet PC than for its equivalent laptop. Depending on the bells and whistles you're looking for, expect to pay anywhere from $1,000 on up.

The handwriting-to-text conversion does not always work the way you wish it would. Just like speech-to-text systems require a trained style of speech to work properly, tablet PCs recognize a trained penmanship easier than the way you may write naturally. A lot of the kinks in these conversion systems have been worked out - but don't plan on handwriting your next novel expecting to be able to convert into a print-ready copy with no problems.

Finally, their smaller size is both an advantage and disadvantage. They are much more mobile than their laptop counterparts, but the viewing area is also smaller. Likewise, the keyboard also shrinks down to accommodate the smaller size, so if you feel like your fingers are already cramped on a laptop-sized keyboard, you'll want to make sure you're going to be able to use the tablet PCs before you buy one.

Nick Smith is a client account specialist with <a target="_new" href="http://www.10xMarketing.com">10x Marketing</a> - More Visitors. More Buyers. More Revenue. For organizational software that will help you take full advantage of <a target="_new" href="http://www.gobinder.com/tablet-pcs.aspx">tablet PCs</a>, visit <a target="_new" href="http://www.gobinder.com">GoBinder.com</a>.

Your Hard Drive is Going to Explode ? Why a UPS is Essential

It's most peoples worst computing nightmare. You wake up in the morning, flip on the computer, and it doesn't boot. Sometimes the problem rears its ugly head as a horrific clacking noise. Other times it simply gives a read error.

At this point, most people panic. The first thing you wonder is whether or not the data is recoverable. There is no universal answer to this. In some cases, a simple scan with some data recovery software is all that it takes to retrieve the contents of the drive. In other cases, if you want it badly enough, it will take thousands of dollars and a shipment of the drive to a clean lab where they will pull the platters inside of the drive and access them that way.

Now you're probably wondering if there's a way to prevent this from happening. Well, you're in luck. Getting a UPS (Uninterruptible Power Supply) is the very best and most effective way to prevent your data from pulling a disappearing act.

While it is not fool-proof, having something that regulates the electricity flowing into your computer can reduce the risk of a drive failure by up to 70%. This figure goes up to around 90% if the computer is being used while in an electrical storm. (My computer repair business always gets a little boost after a thunderstorm, courtesy of the lightning wreaking havoc on people's hard drives.)

Don't just run out and get any UPS. You want to get an intelligent one. The 'intelligent' UPS will regulate the power without having to hit the battery every time the voltage takes a dip which greatly improves battery longevity. They also include options to hook the power supply up to your computer via a serial or USB port so you can monitor what the power is doing. This also gives the option to allow for a soft shut-down if the power goes out and you are away from your desk.

You can get an Uninterruptible Power Supply at most computer stores. Best Buy carries a fairly wide selection of them.

As for brands, I've personally used APC with much success. Opti-UPS is another excellent brand. In fact, I have an Opti that is 6 years old and still works fine, although the batteries now have no life to them. (That's to be expected. Rechargeable batteries only last so long)

Now that you know of the importance of a UPS I would strongly encourage you to invest in one. It is far better to spend $100 now on some preventative maintenance than having to spend much more later on data recovery.

<a target="new" href="http://www.sootahcris.com">Kevin Souter</a> is a full time computer technician. He also operates some <a target="new" href="http://www.eradicatespyware.net">free spyware removal</a> and <a target="_new" href="http://www.tweaksforgeeks.com">computer repair</a> websites.

Buying Cheap Refurbished Laptops

When comparing refurbished laptop models, ask about these specifications:

Central Processing Unit: The CPU or processor is the heart of the computer. The more software you want in your refurbished laptop, the more powerful the processor has to be. A 32-bit processor is less powerful and less expensive than a 64-bit processor.

Operating System: The operating system, or OS, is the graphic interface between you and whatever programs you are running. Windows and Unix are the two main families of operating systems. Windows is the more common interface, and therefore less expensive.

Screen Size: Smaller does not necessarily mean cheaper; some smaller models are just as powerful as some larger models but more portable.

Hard Drive Size: The hard drive, or HD, is the permanent information storage disk inside the unit. HD capacity is measured in gigabytes. A GB is one billion bytes. A byte is a piece of information, such as text, sound, or picture. The larger the HD is, the more software it can handle and the more expensive the laptop will be.

Hard Drive Speed: HD speed is measured in revolutions per minute ? usually 5000 to 15,000 RPM. The faster the HD, the better and more expensive the laptop will be.

Random Access Memory: The RAM is the temporary storage chip that continually updates information while you are using the computer. Today 64 megabytes is the entry level RAM size, suitable for running many programs simultaneously. The greater the storage capacity of the RAM, the more powerful and expensive it is.

Media Bay: The media bay contains the slots for playing and recording CDs and DVDs. Older laptops might only allow the playing of CDs, whereas newer laptops allow you to both play and record CDs and/or DVDs. The more features there are in the media bay, the more you can do with your laptop, and the more you will spend.

Modem: Modems can take the form of dial-up telephone modems, or fast cable or direct satellite linkup modems. The faster your type of modem is, the more easily you will be able to surf the web and the more costly your laptop will be.

The price will be affected by all these specifications, along with added features, how well preserved the chassis is, the name of the manufacturer, and whether you acquire the laptop form the factory or through a private dealer. Private dealers charge less, but beware: not all dealers are up to par with their refurbishing skills. Be sure to go to one that is reputable and experienced.

<a target="_new" href="http://www.i-refurbishedlaptops.com">Refurbished Laptops Info</a> provides detailed information on quality, cheap refurbished laptops by manufacturers like Dell, IBM, Toshiba, and HP, as well as refurbished laptop batteries and related products. Refurbished Laptops Info is the sister site of <a target="_new" href="http://www.e-rackmountcomputer.com">Rack Mount Computers Web</a>.

Testing Flyback Transformer - How to Test and When to Replace It

Nowadays, more and more monitor comes in with flyback transformers problems. Testing flyback transformers arenot difficult if you carefully follow the instruction. In many cases, the flyback transformer can become short circuit after using not more than 2 years. This is partly due to bad design and low quality materials used during manufactures flyback transformer. The question is what kind of problems can be found in a flyback transformer and how to test and when to replace it. Here is an explanation that will help you to identify many flyback transformer problems.

There are nine common problems can be found in a flyback transformer:

a) A shorted turned in the primary winding.

b) An open or shorted internal capacitor in secondary section.

c) Flyback Transformer becomes bulged or cracked.

d) External arcing to ground.

e) Internal arcing between windings.

f) Shorted internal high voltage diode in secondary winding.

g) Breakdown in focus / screen voltage divider causing blur display.

h) Flyback Transformer breakdown at full operating voltage (breakdown when under load).

i) Short circuit between primary and secondary winding.

Testing flyback transformer will be base on (a) and (b) since problem (c) is visible while problem (d) and (e) can be detected by hearing the arcing sound generated by the flyback transformer. Problem (f) can be checked with multimeter set to the highest range measured from anode to ABL pin while (g) can be solved by adding a new monitor blur buster (For 14' & 15' monitor only.) Problem (h) can only be tested by substituting a known good similar Flyback Transformer. Different monitor have different type of flyback transformer design. Problem (i) can be checked using an ohm meter measuring between primary and secondary winding. A shorted turned or open in secondary winding is very uncommon.

What type of symptoms will appear if there is a shorted turned in primary winding?

a) No display (No high voltage).

b) Power blink.

c) B+ voltage drop.

d) Horizontal output transistor will get very hot and later become shorted.

e) Along B+ line components will spoilt. Example:- secondary diode UF5404 and B+ FET IRF630.

f) Sometimes it will cause the power section to blow.

What type of symptoms will appear if a capacitor is open or shorted in a flyback transformer?

Capacitor shorted

a. No display (No high voltage).

b. B+ voltage drop.

c. Secondary diode (UF5404) will burned or shorted.

d. Horizontal output transistor will get shorted.

e. Power blink.

f. Sometimes power section will blow, for example: Raffles 15 inch monitor.

g. Power section shut down for example: Compaq V55, Samtron 4bi monitor.

h. Sometimes the automatic brightness limiter (ABL) circuitry components will get burned.

This circuit is usually located beside the flyback transformer. For example: LG520si

Capacitor open

a. High voltage shut down.

b. Monitor will have 'tic - tic' sound. Sometimes the capacitor may measure O.K. but break down when under full operating voltage.

c. Horizontal output transistor will blow in a few hours or days after you have replaced it.

d. Sometimes it will cause intermittent "no display".

e. Distorted display i.e., the display will go in and out.

f. It will cause horizontal output transistor to become shorted and blow the power section.

How to check if a primary winding is good or bad in a Flyback Transformer?

a) By using a flyback/LOPT tester, this instrument identifies faults in primary winding by doing a 'ring' test.

b) It can test the winding even with only one shorted turned.

c) This meter is handy and easy to use.

d) Just simply connect the probe to primary winding.

e) The readout is a clear 'bar graph' display which show you if the flyback transformer primary winding is good or shorted.

f) The LOPT Tester also can be used to check the CRT YOKE coil, B+ coil and switch mode power transformer winding.

NOTE: Measuring the resistance winding of a flyback transformer, yoke coil, B+ coil and SMPS winding using a multimeter can MISLEAD a technician into believing that a shorted winding is good. This can waste his precious time and time is money.

How to diagnose if the internal capacitor is open or shorted? By using a normal analog multimeter and a digital capacitance meter. A good capacitor have the range from 1.5 nanofarad to 3 nanofarad.*

1) First set your multimeter to X10K range.

2) Place your probe to anode and cold ground.

3) You must remove the anode cap in order to get a precise reading.

4) Cold ground means the monitor chassis ground.

5) If the needle of the multimeter shows a low ohms reading, this mean the internal capacitor is shorted.

6) If the needle does not move at all, this doesn't mean that the capacitor is O.K.

7) You have to confirm this by using a digital capacitance meter which you can easily get one from local distributor.

8) If the reading from the digital capacitance meter shows 2.7nf, this mean the capacitor is within range (O.K.).

9) And if the reading showed 0.3nf, this mean the capacitor is open.

10) You have three options if the capacitor is open or shorted.

- Install a new flyback transformer or

- Send the flyback transformer for refurbishing or

- Send the monitor back to customers after spending many hours and much effort on it.

* However certain monitors may have the value of 4.5nf, 6nf and 7.2nf. Note: Sometimes the internal capacitor pin is connected to circuits (feedback) instead of ground.

Tv rca flyback transformer circuits usually do not have a internal capacitor in it.

If you have a flyback diagram and circuits which you can get it from the net, that would be an advantage to easily understand how to check them.

Jestine Yong is a electronic repairer and a writer. For more electronic repair articles please visit his website at <a target="_new" href="http://www.noahtec.com/electronic-repair-articles.htm">http://www.noahtec.com/electronic-repair-articles.htm</a>

วันอังคารที่ 2 ธันวาคม พ.ศ. 2551

Dusting Your Computer - Keeping it Cool

My mother always told me to dust, but I never did, mostly because I was lazy, but also because I couldn't find any tangible benefit to dusting. I just didn't see how I'd benefit from my room or my things being less dusty. Well now I've gotten a bit older, and I finally found a reason to dust - a cooler running computer. I'm going to give some background on my own system and circumstances first, then run tests before and after dusting, as well as explain how and what I used to dust. Be sure to take a look at this article - with pictures and graphs - plus a whole lot more, at aworldofhelp.com.

I've had the computer in question for a little over two years, a dual AMD Athlon MP workstation that while no longer the top of the line, is still plenty fast enough for what I do. The computer is running at standard speeds and specifications, and has always been very stable - but not 100%. When the system was about a year old I had been getting by with the occasional, roughly once weekly lock up. At that point, I finally spent the time to try and diagnose the problem.

To be perfectly clear, I'm talking about a lock up, where everything stops responding, the screen freezes and I have to reboot, not simply an application crash, which I can usually just blame on Microsoft. My initial thought was that the computer was overheating, specifically the CPUs. I was a little hesitant though because I was running AMD retail processors at standard specifications with AMD retail heatsinks and fans, and I figured that should have been a fine setup. But I've had CPUs overheat before when I was sure that was the problem and this just felt like it now. I did some research online and it looked like the AMD cooling solutions were somewhat underwhelming performers, so I broke down and bought new heatsinks and fans. These still weren't top of the line, but they reduced my CPU temperatures immediately by about 20%.

In unscientific testing I'd say my computer was absolutely more stable after the reduction in temperature. I estimate the weekly lockup became a monthly or even every other monthly lockup. This clearly isn't perfect for a system that really should be 99.99% stable, but it was a big improvement, and I let the problem go for a while. I will note that as many of you many assume, this computer is always on, twenty-four hours a day, seven days a week.

Anyway now it's another year later and my computer is increasingly unstable again. I'm not going to go out and get better heatsinks and fans again, as I'm sure the improvement would be less than before. My next though was about how dusty the whole system is. I know I should have dusted it once in the last two years, but I never got around to it. I'd say I live in an average environment in terms of dustiness, not especially better or worse, and I just never thought it would make a very significant difference in my CPU temperature. As you'll see, I was completely wrong - which incidentally might make my mother right.

Almost all users should really consider the results of both tests, possibly giving more weight to the one which most closely matches your typical computing. Even if you run predominantly business applications, you'll almost certainly occasionally do something that falls under this content creation test, editing pictures or an occasional home movie, for example. So consider all the tests, don't just focus on one graph.

Should you dust your computer? Yes, why not, it can't hurt. But really, there are tangible benefits of cleaning your computer, even if it seems stable right now.

Computers and electronics in general don't like heat. Dust blocks fans in your case, which generally cool you CPU, video card and motherboard components. Dust also blocks fans and their airflow into and out of your case. Cool air needs to be brought into a case, and then the host air dispelled. If the airways are blocked, system temperature can rise quickly. If your computer is stable but the CPU is running too hot, you cut down on its lifespan, potentially quickly.

More important to many people though, may be the result of that first heat related computer lock up. Even if it's never been a problem before, if your computer crashes at the wrong time it can be catastrophic. Usually mine just locks up when I'm away from it, or overnight, and I just turn it back on and restart Firefox and haven't lost anything important. But last week it locked up with unsaved graphs for my last article and Excel chose no to auto save. I spent the hour it took to redo them considering ways to eliminate these lock ups.

Of course, reducing heat is also always a priority for people who overclock their CPU. For those that don't know, overclocking is running a CPU at a higher frequency than it was sold to run at. For example, you could take your Intel Pentium 4 that is running at a "clock" rate of 2 GHz, and try to run it at 2.1 GHz, 2.5 GHz, faster speeds, or anywhere in between. I have an old dual CPU system that was supposed to run at 366 MHz. Instead I ran the chips at 500 MHz each, which was a huge performance gain. Overclocking is actually a great way to get more "free" performance out of a system, as long as you can maintain stability. Usually the single biggest factor for success is reducing heat as much as possible.

Another thing to note is that while it is very important to keep CPU heat to a minimum, hard drives, video cards, and other components all need to be kept cool as well. In fact, I don't really know for sure that my CPUs are the current problem. I think they are, but my next guess (if I'm correct that it's a heat problem) would be my video card, since I've checked, and it runs really hot.

Consider this as well, if my CPU were to actually stop working because it was too hot, it would probably be a gradual process, and I could fix the situation by purchasing a replacement. If my hard drive crashes and ultimately loses data, that could be a much more problematic situation. I could replace the drive, but recovering the data could be far more difficult than just replacing a CPU.

I opened up the system and saw more dust than computer. All the fans were covered in dust, and their airflow was totally blocked. I put the case back on and took temperature readings of my computer both idle and when working. The tests are all run are on the following system:

CPU - Dual AMD Athlon MP 2000+ (1.67 GHz) Motherboard - AMD K7-D RAM - 1024 MB RAM (2 x 512 MB registered DDR 2100) Video Card - Matrox Parhelia AGP 128 MB HD - Segate 5400 rpm- st320410a Windows XP SP2

I picked that unexciting hard drive because it was the only one I had that reports temperature.

For the idle readings the computer was freshly booted into Windows. To get the computer running at full load I ran two instances of Prime95, a math application that will max out a CPU (2 copies running, one each for 2 CPUs), and copied 2 GB of Music on the hard drive to another folder on the same drive. The entire process took about half an hour.

Without anything to compare them to, those numbers for the most part aren't terribly interesting. My only reaction was that 63 degrees Celsius seems pretty hot, and the idle CPU temperatures aren't too wonderful either. Remember, each CPU type has a different recommended temperature range. 63 degrees may be too hot for mine, but could be either acceptable, or perhaps way too hot for your own. Regardless, you hopefully will notice a relative reduction in temperature after dusting.

Dusting the computer

As I said, I've never dusted a computer before, but I came up with what ended up being a reasonable plan. I bought compressed air and a small brush from staples for $7 total and used a rag I have here. I made sure to unplug my computer, grounded myself to discharge static electricity by touching something metal other than my computer, opened up the case and was ready to go.

As long as you make sure your computer is unplugged, don't get anything wet, and are gentle while you have it opened, you really shouldn't damage anything. For the most part, the inside of your computer is delicate, but it isn't brittle. The most notable exception is your CPU. If you were to disconnect it and pull it out of the motherboard you would expose pins on the bottom that are in fact extremely delicate.

You could do a really thorough job by taking everything apart and getting all the dust out, but I didn't want to spend that much time doing it and I figured if I left everything connected their was less chance I'd mess something up. So I used the air, brush and rag and got the dust off the computer, taking the most time to clean the fans and the holes they blow out of.

I ran the same tests again, and the results were dramatic.

Idle, CPU 1 saw an 18% reduction in temperature, while CPU 2 is 10% cooler. That's very important, as all those hours my computer is sitting doing very little it's going to be considerably cooler.

At full load, CPU 1 is 21% cooler and CPU 2 is 12% cooler. These are again very impressive results, and very important as well. I have had lock ups when video encoding and doing other CPU intensive tasks, and now the chips should be running cooler while doing those.

It's interesting that originally CPU 1 was hotter than CPU 2, and after the cleaning they switched. An important fact is that the temperature reporting on this type of dual AMD Athlon system is generally uneven. That said, CPU 1 was easier to dust around because the DVD drives were in the way of CPU 2, so I probably did a better job cleaning the former and there is still likely room for improvement in cooling the latter.

One other note, I kept track of the fan speeds before and after cleaning, and I saw about a 2% increase in the CPU fan speeds after I dusted. I wasn't expecting this at all, and certainly can't be certain that this will always result from dusting, but it could be very interesting for overclockers trying to eak out every last bit of fan performance.

The hard drive temperature saw a 9% improvement while idle after dusting, and again a 9% improvement at full load. It's a nice temperature reduction for a mechanical component that will be grinding away for thousands of hours over the life of your computer.

The case temperature stayed the same throughout all the tests.

Conclusion

All in all I was surprised the results were so dramatic. I expected few degrees for the CPUs and maybe one for the hard drive, but to see a 20% reduction in temperature is just great. There is defiantly room for improvement as well. The CPU fans have covers that I could have taken off and gotten more dust out, and as I mentioned reaching one of the CPUs was harder than the other. Further, I'd say I got most of the dust inside my computer, well over 90%, but I still saw some that proved more challenging to clean that I was willing to bother with. Taking all the cards out and thoroughly cleaning the whole system would have no doubt led to even better results.

My system has maintained the cooler temperatures so far, a week after the cleaning, and I haven't had a lock up since. I can't be certain I've solved the lock up problem, but it does appear I have for now. At the very least, I can be sure CPU heat is not the problem, as now they are running at very acceptable temperatures. Your own results will vary, and may not be as dramatic if your computer wasn't as dusty as mine. Regardless, you should see some reduction in component temperature after cleaning your system.

All in all I recommend you take a look around and inside your computer to see how it looks. If it's dusty, $7 and an hour of your time seems like a good investment to increase the life of your computer and prevent system lock ups. I suspect many people suffer the occasional heat caused lock up, it just isn't obvious what the problem is, and they don't occur often enough to be a serious concern. But remember, even if you only have one heat caused lock up in the entire life of your computer, it could come at the worst time, or cause permanent damage.

Steve Perlow is the founder of <a target="_new" href="http://aworldofhelp.com">aworldofhelp.com</a>, where you can find the aworldofhelp Top Picks in desktop and notebook systems. Visit aworldofhelp.com to get answers from real people to your questions about technology, travel and more.

วันจันทร์ที่ 1 ธันวาคม พ.ศ. 2551

SED is Coming

One of the bigger challenges facing display manufacturers is to develop a picture with the same warm characteristics as Cathode Ray Tube, but with far less weight and size.

The disadvantage of CRT, however is the size, weight and power consumption. The focus has now shifted to flat panels. Canon and Toshiba are about to introduce a new display technology called SED or Surface-conduction Electron-emitter Display.

The SED consists of layers of glass plates seperated by a vacuum. One plate is mounted with electron emitters, much like the electron gun in the CRT. The number of emitters are equal to the number of pixels. Another layer, is coated with a flourescent substance that reflects light at different wavelength, than the incident light.

When a voltage is applied, electrons are emitted from one side of a very narrow slit, and are scattered and accelerated by voltage applied on the other side of the slit, causing collision with the flourescent coated plated and light is emitted. To the trained eye, a visible lag can be noticed when viewing LCD's.

SED is similiar to CRT with the light emission theory, and the manufacturers claim the dynamic color can be expressed in sharp pictures and faster responses than LCD's or plasmas. Since no deflection of beam is required, screens of more than 40 inches and only centimetres thick can be created. Power consumption is claimed to be one third that of PDP and LCD's.

The introductory cost, at this point may be of some concern, however as with all new technologies, it can be expected to decrease as improvements are made. We keep on the lookout.

Permission is granted to publish this article either electronically or in print. Publication is granted free of charge as long as the byline is included and the article is published in its entirety.

Dale Davidson is the publisher of an on-line newsletter "the eShopper on-line that provides free info, products and services to on-line consumers.

With an extensive background in electronics, and membership in the IEEE, ASME among others, the newsletter provides regular info on from consumer electronics products.

Can be reached via email or visit website: <a target="_new" href="http://www.eConsumershop.com">the econsumershop</a> .