Scouting Out Hard-To-Find Components

January 31st, 2008

Modern electronics make use of a number of electronic components. Semiconductors are an integral part of many electronic components. Semiconductor technology has been developing over the years, and these days, most electronic parts make use of semiconductor technology. Thus, most of the integrated circuits and diodes that we use (among other things) make use of semiconductor technology.

When dealing with electronics, it is necessary to understand what semiconductors are and how they work. Now, the substances that we see around us can be divided into three main categories based on the way in which they conduct electric current. These three categories are: conductors, non-conductors, and semiconductors. To put it simply, materials that allow the flow of electrical current are called conductors, and the ones that do not allow this flow are called non-conductors. A large number of metals fall into the first category while materials like plastic and wood fall into the second. A semiconductor is somewhere in between these two categories. Silicon is one of the most popular semiconductors that are used.

Semiconductor technology continues to progress day by day. Thus, every day sees yet another component becoming obsolete. This is bound to happen thanks to the great leaps that science seems to be making on a regular basis. A new development somewhere may completely revolutionize some of the processes, thereby making existing instruments and components redundant. Technological progress does have a way of ousting existing procedures to make way for newer ones. However, progress in technology is not the only reason why certain components become obsolete.

These days, with environmental concerns being topmost on everybody’s mind, it is natural for governments to pass laws pertaining to the use of hazardous materials. After all, everybody seems to be thinking green nowadays. However, such laws sometimes end up banning components that are commonly used. This in turn, adversely affects the electronic machinery that is in use, and in some cases, may render them obsolete as well. Thus, buyers of certain electronic components find it difficult to get hold of certain integral parts.

Luckily for buyers, however, locating hard to find electronic parts is no longer all that difficult. The Internet has opened up all kinds of boundaries. Buyers and suppliers can easily come into contact and place their orders over the online world. Everything from obsolete semiconductors to difficult to locate integrated circuits is now available within a few mouse clicks. So even if some components become difficult to find, the buyers of today really have no reason to worry.

We help you locate electronic components. Visit: Electronic Components, Integrated Circuits, and Hard to Find Electronic Parts.

What Are Ink Refills Made Of

January 30th, 2008

What Are Ink Refills Made Of?

Almost all of the many types of inks

Monitor Blur Problem - The Easy Way To Repair It

January 29th, 2008

Monitor Blur Problem - The Easy Way To Repair It

Among all the electronic repair articles that I have sent to you, this method is consider a little bit dangerous if you do not know what you are doing. For those who are new in this field I suggest that you only apply it with the help of a senior tech. Study this article carefully and the necessary precautions that one should take before starting to use this trick. However, if you think that you have the courage to try, then go ahead to perform the test.

A 15” Philips 105s7 Monitor came in with the complaint of display blur. Normally the first thing that a technician will do is to tune the focus adjustment knob at the flyback transformer to get a sharp picture back. However, in this case while tuning the focus instead of expecting a sharp picture, you get a brighter raster (white background) with flyback retrace lines across the screen. Usually when you turn the focus knob, only the character get sharper without affecting the raster and this is also true when you tune the screen (G2) knob adjustment, only the raster will have effect but not the focus.

Since adjusting the focus control has effect on the raster, this clearly tells us that there must be something that had gone wrong in the monitor. With this problem, I could only think of 3 areas that I have to check i.e; a shorted flyback transformer divider network, a defective CRT socket and a faulty picture tube. In order to confirm if the flyback transformer divider is shorted or not is very simple. Just use a Monitor blur buster (MBB) and defeat the original focus and screen cable by connecting the focus and screen cable from the Monitor blur buster. Now tune the focus or screen control at the MBB to see if the picture gets sharp or not. If you get a sharp picture we can conclude that is the flyback transformer divider network that is faulty and if the picture stills blur then it can only be the CRT socket faults or a bad picture tube.

In order to confirm if the CRT socket is the cause of the problem, one just has to replace with another working CRT socket to see if there is any improvement in the picture. If it still blur then I believe you are now sure as which one is the true cause of the picture blur problem-it is the CRT or picture tube! If it is picture tube problem, then you may ask, can it be repair or not since a picture tube is a vacuum tube that can’t be disassemble? Yes, it can be done but with some precautions that you need to take.

To repair such problem, one must first understand how a picture tube was constructed especially the electron gun. I won’t go too details about electron gun but I will let you know that the focus and the screen G2 plate is the nearest and if there are any dirt’s or particles that had happened to be between the two plates, then it would surely affect the display (picture becomes blur, dim or too bright with flyback lines).

Once you have certain that the cause of the problem is picture tube, now remove the CRT board from the neck of the picture tube and locate the pins of screen (G2) and focus. If you look at the photo, most of the CRT pin outs is almost the same except to some Sony Trinitron tubes. Connect an alligator clip between the focus pin and cold ground and the G2 pin to the shaft of the flat type screw driver. The reason for connecting the alligator clips in such a way so that the generated Monitor high voltage (about 24 kvdc) can be use to spark off the internal shorts in the electron gun between the focus and G2 plate.

Before you switch on the Monitor, please make sure you disconnect or unplug the VGA signal cable from the CPU otherwise when the discharge begins it may destroy the CPU VGA card. Not only that, please check any surrounding in the Monitor as no extra wires or cables touches the power section, if not it may blow the power supply. As mentioned in the above first paragraph that this method really need you to be extremely careful and alert so that nothing would happen when you start to discharge the high voltage through the anode cap.

If you are ready now, hold the handle of the screw driver (remember, the handle have to be thick otherwise certain of the high voltage may jump across and discharge through your hand) with your left hand and power “ON” the Monitor. Once the high voltage have present (with the rushing sound you’ve heard), now switch off the Monitor by pressing the front panel on/off button, you then quickly poke in the screw driver shaft to the anode before the high voltage being discharge by the bleeder resistor in the flyback transformer. In other words, we want to utilize that short moment of the high voltage to spark off the shorts in the electron gun before the high voltage being fully discharged.

Normally you will hear a “pop” sound when the high voltage arc through the screw driver shaft at the anode cap. Repeating this for few times and the shorts definetely will go away. Connect the CRT board back and test the Monitor to see if the problem has been solved or not. Assuming the Monitor still blur after few of the discharged, you can always reverse the alligator clips where now you are connecting the G2 pin to cold ground and using the focus point to poke through the anode cap. This will usually clear the shorts away

Remember, the blur problem in this article is totally different from the blur problem (blooming) caused by a defective flyback transformer divider network where you need a Monitor blur buster to solve it. Using the method above I’ve solved lots of this Monitor blur problem whether it is a 14” or 21” Monitor!

Jestine Yong is a electronic repairer and a writer, for more electronic repair information, please visit his website at http://www.jestineyong.com