Inspection and repair of damage of monitor row tube

Row tube Damage is the most common problem in the maintenance of the display, and repeated bad pipe is a headache, so what is the root cause of the problem? In this article, I will explore and summarize the problem in the maintenance practice.

In general, there are several reasons for the damage of the line tube: 1. The quality of the pipe has unforeseen defects, the use of natural damage. 2. The capacity of the inverter capacitor decreases or opens the circuit, and the amplitude of the reverse pulse increases abnormally. 3. The line power supply voltage is too high that the line pulse amplitude is abnormally elevated. 4. Line load short circuit, leakage caused by the flow, where the line load is the line output transformers, deflection yoke, s correction capacitor components. 5. The line frequency is too high or too low. 6. Insufficient incentive to do the work. 7. The performance of the row damping diode becomes bad. 8. Human factors. In the actual maintenance of the 1th situation is the main cause of damage to the pipe, the general replacement of the line tube can be. The 2nd situation I see is caused by the failure of the inverter capacitor open welding. 5, 7 of cases actually rarely happen, here is not said. The 3rd kind of case causes the row tube breakdown to be many, especially uses the buck type DC/AC converter circuit the line two times switching power supply is especially prominent. When this kind of power supply switch tube breakdown, the row tube is often because the line voltage is too high and breakdown, and when the line tube breakdown also will cause the switch tube because of overcurrent and damage, both reciprocal causation, complement each other, overhaul should be checked, can not be omitted. It is worth noting that when the line power switch tube damage measurement results are not all breakdown, individual will be shown as D, s polar conduction pressure drop increase, if not replaced also will be repeatedly burned line, I have seen such an apple monitor, changed IRF9630 just good. Then there is a buck-type line two times switching power supply of the inductive coil may also be caused by the burning of the line voltage abnormally elevated, resulting in damage to the line tube (there is a stage Philips display batch damage this inductor, but as if the line tube is not damaged, may be good circuit protection design). On the 4th case, first of all, the display of the output transformer technology requirements are higher than the color TV line output transformers, the probability of damage is very low, should not be determined to determine the damage of the package. From the large number of monitors I have picked up, many maintenance workers are not aware of this. Judge row output transformer damage should be prudent, because the display line output transformers not only expensive and not easy to buy, of course, the deflection yoke is more so. The general multi-frequency display has at least two s-corrector capacitor, we can according to the different position can be called on the S-correction capacitor, the lower s correction capacitor. In practice, I found that the lower s correction capacitor is more damaged, at this time the line amplitude will change. At present, s capacitance breakdown, leakage of the amplitude widening, line current increase, the operating temperature rise, the pipeline will be thermal breakdown. Of course, the same problem can be caused by the breakdown of the row amplitude adjustment tube and the lower damping diode.

I found in practice that the 6th situation raises a high probability of a problem, and the 8th is not easy to think about. The operating temperature of the pipe is closely related to its base-pole excitation, and I have observed many kinds of monitors such as Adi, Philips and EMC with Oscilloscope, and found that the excitation waveform of the Philips display tube is almost perfect (relative), its working temperature is not very high at all. In practice, the problem of Philips display line tube is less, compared with the same grade Adi, the excitation waveform of the tube is not very good, the working temperature is high, and the damage of the line tube is much more obvious. This may be Tun, because like BU2508, 2520, 2522 is the product of Philips. The general design in order to allow the completion of the saturation of the line pipe, often in line with the row to promote the transformer between the current limiting resistor in parallel a capacitor and a reverse diode. Usually this capacitor is organic electrolytic capacitor, the capacity from a few to hundreds of, with the increase in the use of time this capacitor will appear loss increases, capacity reduction (when its damage after the use of pointer multimeter is usually not measured out, the general use of digital multimeter capacitive block easier to find problems. This is because the capacity of capacitance is measured by alternating current (as if it were 1KHz), capacitance of the work is closely related to the frequency, these bad capacitors are generally high frequency characteristics of the bad, in the low-frequency circuit may not be able to make it, the line pipe because of the deterioration of working conditions and severe fever, the final thermal breakdown. The Philips Circuit also has an accelerated capacitor, but that is a small capacity of the inorganic capacitance. It is necessary to check this type of problem using an oscilloscope, but it is worth noting that the waveforms of each display are different and cannot be applied mechanically. For example, an individual EMC display, its waveform amplitude will be smaller, but will not affect the normal operation of the line, in order not to detours to accumulate more measured data. In the selection of electrolytic accelerated capacitor, if the original position allows, should try to use large size, high pressure, high operating temperature, and to avoid the source of heat. This is because it is highly demanding at high frequencies, and if you touch it at work, you know it may be hot. Let's talk about the 8th situation, I often see someone in the press to use color TV Line tube on the monitor, I always want to ask: This can be repaired? I have had to use BU508 when monitor row tube experience, that about two hours after BU508 due to fever serious breakdown, had to put only a BU2508, long time work is only slightly warm. For a detailed analysis of this, please refer to the Electronic industry publishing house "new display circuit analysis," a book No. 228 to 232 pages, there is a more early out of the book, probably called "Great Wall display circuit principle and maintenance" bar. I want to say another thing here?? Be careful that your line of work is false. 5 years ago I had mail order a few C4769 from a Guangdong company, after the machine found a severe fever. After the examination began to suspect C4769 is false, and then carefully contrasted with the genuine. It's better to be surprised than not to know. There are four surfaces in five tubes.Grinding, the original handwriting is printed on, and the fake is actually laser lettering! The year before last I bought 20 bu2520df, on the machine and found the problem of severe fever, the excitation waveform obviously insufficient. The first thing that comes to mind is this: another fake. In comparison with the real appearance of the original did not find the flaw, using a multimeter measurement found that this bu2520df b-e between the dozens of resistance. From then on I will pay more attention to observe the market on the false line tube, it is surprising that the electronic market in Harbin to sell the display of the majority of false, very little authentic. The main means of forgery, but there are "breakthrough" to fake C5250, for example, the surface and the original is the same, but the pin is obviously wide. Now Harbin electronic market has been almost not see the real BU25XX Series line of pipe! Whether it is laser lettering as the basis for judging authentic is already outdated, now the major cities have to sell laser engraving machine! Because I often debunk the sale of fake pieces dealer tricks, so I know the high boss smiled at me as a?? Diao min. In this, I would like to say to the profiteers: you have worked hard.

Here are a few practical examples I have encountered in practice, hoping to help.

Example 11 Wanstrow1428 display without grating, through the check line tube breakdown. Replace the row tube, a few days after the line tube again breakdown. Check the power supply voltage is no problem, again a good line tube, after the electricity, pay close attention to the temperature rise of the tube. It was found to have a severe fever in a short time. Suspected line excitation is insufficient, the measurement series line to push the transformer and row nanotube-based pole of the accelerated capacitor, found that its capacity from 10 to 1? Replace it, the row tube temperature is normal.

Example 2 a LEC1428 monitor line tube breakdown, replace the line tube after delivery user. About half a month later, the user returned to the machine, after the investigation found that the line tube breakdown. This will check the scope of expansion, the inverter capacitor, s correction capacitor, line output, line power supply voltage has not seen abnormal. Replace the new line again, add electricity, the line can work, but the tube temperature is significantly higher. Using oscilloscope to measure the B-leg of the tube, the waveform is slightly blurred. It is not normal to accidentally measure the 12V end of the T601 when checking the driving level of the line and find that it has obvious waveform. Check the row-driven decoupling capacitor C614 (100?25v) and find its capacity is only 0.2? After the replacement of the 12V-terminal waveform is very weak, and the line B-foot waveform becomes clear, rising along, down along the "clean and neat", long working temperature is only a slight temperature. This example also belongs to the line incentive insufficiency, from Example 1, example 2 can see this kind of fault typical characteristic is: not immediately burn the line tube, but the row tube work temperature is high, the time long line tube finally because of overheating and damage. This problem is also more on Philips big screen.
Row tube Damage is the most common problem in the maintenance of the display, and repeated bad pipe is a headache, so what is the root cause of the problem? In this article, I will explore and summarize the problem in the maintenance practice.

In general, there are several reasons for the damage to the row tube: 1. The quality of the line tube has unforeseen defects, the use of natural damage. 2. The capacity of the inverter capacitor decreases or opens the circuit, and the amplitude of the reverse pulse increases abnormally. 3. The line power supply voltage is too high that the line pulse amplitude is abnormally elevated. 4. Line load short circuit, leakage caused by the flow, where the line load is the line output transformers, deflection yoke, s correction capacitor components. 5. The line frequency is too high or too low. 6. Insufficient incentive to do the work. 7. The performance of the row damping diode becomes bad. 8. Human factors. In the actual maintenance of the 1th situation is the main cause of damage to the pipe, the general replacement of the line tube can be. The 2nd situation I see is caused by the failure of the inverter capacitor open welding. 5, 7 of cases actually rarely happen, here is not said. The 3rd kind of case causes the row tube breakdown to be many, especially uses the buck type DC/AC converter circuit the line two times switching power supply is especially prominent. When this kind of power supply switch tube breakdown, the row tube is often because the line voltage is too high and breakdown, and when the line tube breakdown also will cause the switch tube because of overcurrent and damage, both reciprocal causation, complement each other, overhaul should be checked, can not be omitted. It is worth noting that when the line power switch tube damage measurement results are not all breakdown, individual will be shown as D, s polar conduction pressure drop increase, if not replaced also will be repeatedly burned line, I have seen such an apple monitor, changed IRF9630 just good. Then there is a buck-type line two times switching power supply of the inductive coil may also be caused by the burning of the line voltage abnormally elevated, resulting in damage to the line tube (there is a stage Philips display batch damage this inductor, but as if the line tube is not damaged, may be good circuit protection design). On the 4th case, first of all, the display of the output transformer technology requirements are higher than the color TV line output transformers, the probability of damage is very low, should not be determined to determine the damage of the package. From the large number of monitors I have picked up, many maintenance workers are not aware of this. Judge row output transformer damage should be prudent, because the display line output transformers not only expensive and not easy to buy, of course, the deflection yoke is more so. The general multi-frequency display has at least two s-corrector capacitor, we can according to the different position can be called on the S-correction capacitor, the lower s correction capacitor. In practice, I found that the lower s correction capacitor is more damaged, at this time the line amplitude will change. At present, s capacitance breakdown, leakage of the amplitude widening, line current increase, the operating temperature rise, the pipeline will be thermal breakdown. Of course, the same problem can be caused by the breakdown of the row amplitude adjustment tube and the lower damping diode.

I found in practice that the 6th situation raises a high probability of a problem, and the 8th is not easy to think about. The operating temperature of the pipe is closely related to its base-pole excitation, and I have observed many kinds of monitors such as Adi, Philips and EMC with Oscilloscope, and found that the excitation waveform of the Philips display tube is almost perfect (relative), its working temperature is not very high at all. In practice, the problem of Philips display line tube is less, compared with the same grade Adi, the excitation waveform of the tube is not very good, the working temperature is high, and the damage of the line tube is much more obvious. This may be Tun, because like BU2508, 2520, 2522 is the product of Philips. The general design in order to allow the completion of the saturation of the line pipe, often in line with the row to promote the transformer between the current limiting resistor in parallel a capacitor and a reverse diode. Usually this capacitor is organic electrolytic capacitor, the capacity from a few to hundreds of, with the increase in the use of time this capacitor will appear loss increases, capacity reduction (when its damage after the use of pointer multimeter is usually not measured out, the general use of digital multimeter capacitive block easier to find problems. This is because the capacity of capacitance is measured by alternating current (as if it were 1KHz), capacitance of the work is closely related to the frequency, these bad capacitors are generally high frequency characteristics of the bad, in the low-frequency circuit may not be able to make it, the line pipe because of the deterioration of working conditions and severe fever, the final thermal breakdown. The Philips Circuit also has an accelerated capacitor, but that is a small capacity of the inorganic capacitance. It is necessary to check this type of problem using an oscilloscope, but it is worth noting that the waveforms of each display are different and cannot be applied mechanically. For example, an individual EMC display, its waveform amplitude will be smaller, but will not affect the normal operation of the line, in order not to detours to accumulate more measured data. In the selection of electrolytic accelerated capacitor, if the original position allows, should try to use large size, high pressure, high operating temperature, and to avoid the source of heat. This is because it is highly demanding at high frequencies, and if you touch it at work, you know it may be hot. Let's talk about the 8th situation, I often see someone in the press to use color TV Line tube on the monitor, I always want to ask: This can be repaired? I have had to use BU508 when monitor row tube experience, that about two hours after BU508 due to fever serious breakdown, had to put only a BU2508, long time work is only slightly warm. For a detailed analysis of this, please refer to the Electronic industry publishing house "new display circuit analysis," a book No. 228 to 232 pages, there is a more early out of the book, probably called "Great Wall display circuit principle and maintenance" bar. I want to say another thing here?? Be careful that your line of work is false. 5 years ago I had mail order a few C4769 from a Guangdong company, after the machine found a severe fever. After the examination began to suspect C4769 is false, and then carefully contrasted with the genuine. It's better to be surprised than not to know. There are four surfaces in five tubes.Grinding, the original handwriting is printed on, and the fake is actually laser lettering! The year before last I bought 20 bu2520df, on the machine and found the problem of severe fever, the excitation waveform obviously insufficient. The first thing that comes to mind is this: another fake. In comparison with the real appearance of the original did not find the flaw, using a multimeter measurement found that this bu2520df b-e between the dozens of resistance. From then on I will pay more attention to observe the market on the false line tube, it is surprising that the electronic market in Harbin to sell the display of the majority of false, very little authentic. The main means of forgery, but there are "breakthrough" to fake C5250, for example, the surface and the original is the same, but the pin is obviously wide. Now Harbin electronic market has been almost not see the real BU25XX Series line of pipe! Whether it is laser lettering as the basis for judging authentic is already outdated, now the major cities have to sell laser engraving machine! Because I often debunk the sale of fake pieces dealer tricks, so I know the high boss smiled at me as a?? Diao min. In this, I would like to say to the profiteers: you have worked hard.

Here are a few practical examples I have encountered in practice, hoping to help.

Example 11 Wanstrow1428 display without grating, through the check line tube breakdown. Replace the row tube, a few days after the line tube again breakdown. Check the power supply voltage is no problem, again a good line tube, after the electricity, pay close attention to the temperature rise of the tube. It was found to have a severe fever in a short time. Suspected line excitation is insufficient, the measurement series line to push the transformer and row nanotube-based pole of the accelerated capacitor, found that its capacity from 10 to 1? Replace it, the row tube temperature is normal.

Example 2 a LEC1428 monitor line tube breakdown, replace the line tube after delivery user. About half a month later, the user returned to the machine, after the investigation found that the line tube breakdown. This will check the scope of expansion, the inverter capacitor, s correction capacitor, line output, line power supply voltage has not seen abnormal. Replace the new line again, add electricity, the line can work, but the tube temperature is significantly higher. Using oscilloscope to measure the B-leg of the tube, the waveform is slightly blurred. It is not normal to accidentally measure the 12V end of the T601 when checking the driving level of the line and find that it has obvious waveform. Check the row-driven decoupling capacitor C614 (100?25v) and find its capacity is only 0.2? After the replacement of the 12V-terminal waveform is very weak, and the line B-foot waveform becomes clear, rising along, down along the "clean and neat", long working temperature is only a slight temperature. This example also belongs to the line incentive insufficiency, from Example 1, example 2 can see this kind of fault typical characteristic is: not immediately burn the line tube, but the row tube work temperature is high, the time long line tube finally because of overheating and damage. This problem is also more on Philips big screen.