Electromagnetic furnaces are one of our usual domestic appliances, where heat-resistant ceramic plates are used on the surface, where transgenic currents generate magnetic fields through the wire below the ceramic plate, and when magnetic lines in the magnetic field pass through the bottom of iron pans, stainless steel pans, etc., generate vortex that heats the bottom of the pan quickly to the purpose of heating the food. Because of the high frequency of appliances that are used on a daily basis, the failure rate is high, so we're going to talk today about how the electromagnetic furnace can be maintained。
There are about three common failures in the electromagnetic furnace:
Explosive - fire insurance and igbt。
This is reflected in the failure of electricity to react and the non-working of the whole machine. We unplugged the machine, and we found out that the insurance burned, and it exploded so badly that it was all black on the glass wall. Further examination will show that the igbt under that big radiator has also broken through, and sometimes even a whole stream bridge has been burned, but the whole bridge is much stronger than igbt and normally only igbt. What about the electromagnetic furnace。
What about the electromagnetic furnace
In this case, we should not rush to replace the spare parts test machine. We need to find out if there are any other bad things. In this case, i measured all the major resistance broadly in the circuits, and the two triodes (8050 8550) driving igbt also measured to see if there were drums for 300v filtering and 0. 33uf resonating. If that's all right, replace all the bad parts except igbt. At this point, it is normal to test b-ovs for +5v, +15v or +18v, igbt. Only when these voltages are normal can igbt be installed. This will eliminate most of the blast failure。
What if the electromagnetic furnace is broken
2 unrespondable, but not explosive
The test machine, the whole machine, was not working, the electromagnetic furnace was removed and the fuse was found to be intact。
This is usually the case when the electric transformer chip of the electromagnetic furnace is burned, which generally generates 18v voltage, then becomes +5v voltage by 7805 for cpu work, without +5v, with cpu not working, of course, the whole machine is not working. In electromagnetic furnaces, such chips are generally used as viper12a, viper22a, thx203h etc. The power transformer chip is measured on the outer edge of the chip to see if there is a small device with collateral damage, and if so, replace it。
Three, turn it on
Such failures require a clear understanding of the meaning of the code before purposeful maintenance. There's a lot of code down the electromagnetic furnace on the internet, and we can use it. Such malfunctions are typically electrically resistant transformations of high-probability bodies, which can be measured in one place and replaced by variables. At the same time, we need to check the single level of the intersensor, 300v/5uf capacitor, heat-sensitive electrical resistance and electromagnetic furnaces. As long as these locations are identified, such failures can generally be eliminated. The few may also have been caused by damage caused by lm339 and may be verified by proxy。
4 fragmented, some buttons not responding。
This type of failure is best fixed, usually when the key is broken or when the keyboard is dirty, or when the key is pressed or the keyboard is cleaned。
5 cpu bad
Such failures are generally not repairable and it is best not to waste time, as such cpus are difficult to reach。
6 unheated or intermittent heating。
These malfunctions are difficult to repair, temperature detection of electrical resistance, simultaneous oscillation circuits, igbt-driven, igbt c-high voltage protection circuits, current detection circuits, pwm-modified circuits, and cpu circuits may all be associated with such failure. Fixing such failures is a test of our patience。
What about the electromagnetic furnace? When you fix an electromagnetic furnace. The first feeling is that it's clean as an electromagnetic furnace... Dry and repaired. The opposite is more difficult. I think i'm gonna fix my friends. Why? The reason for this is the intangible resistance caused by dirty, damp, corrosive, and the eccentricity caused by its invisibility and failure. We're not talking about weird breakdowns today. Today we talk about the most common malfunctions. The following points have been captured because of the common pattern of failure ... And the majority. It can be said that 80 per cent of the electromagnetic furnaces can be repaired. First of all, the light is on, the alarm is not hot or the heating is intermittent. (of course low voltage 5v, 18v is normal). Practical experience has shown that for low- and medium-sized electromagnetic furnaces below $500. No matter what brand and type. The following elements are more damaged as long as the signal light does not heat the alarm, or the electromagnetic furnaces that are intermittently heating. An icon (1) (2),, and (8) (9) is prepared to explain the current rate of component damage from high to low by analogy. I'm simple. I'm brief about it. It's easy for beginners to understand. See:
The signal light is on, the alarm is not hot or the heat is intermittent. For electromagnetic furnaces that have been in use for more than two years, the most easily damaged element is the micro-movement switch (in graph 1) which causes cpu to misjudge ... Resulting in a signal light warning that the heat is not heated or intermittently heated. All repairs should be replaced at a time. The second should be checked (chart 2) to detect electrical resistance, which can be cut off (in the range of 220-500k. The maintenance shall be based on the resistance of the detachment test. Third should be checked (figure 3) for power transferable resistance (different types of resistance ... Typically in 1k-20k) to the middle ... Without misalignment or damage to igbt tubes. Fourth should be checked (chart 4) for current sensors, primary resistance is zero, secondary resistance values (with different types of electromagnetic furnaces) are generally not less than 100 om, and no higher than 1 k om. It's best to switch to the barrier. The fifth should be checked (figure 5) lm339 and most maintenance staff do not have a specialized tester to replace it. Sixth should check (chart 6) electric fans. A fan circuit or fan has a broken fan. It causes the electromagnetic furnace to heat up and protect itself for only a few minutes。
Seventh should be checked (in figure 7) for high voltage power, most of which has a five-micro capacity, with damage not only to alert the heat, but sometimes to explosive igbt tubes. The eighth shall be found (in figure 8) as a bottom temperature control sensor with a normal resistance of 100 k. (it is a negative temperature coefficient electrical resistance. It is reduced by the temperature barrier.) its damage has a malfunctioning display code (the different types of machine codes show different). The ninth should be checked (in figure 9) for high-frequency resonance caps with a general capacity of approximately 0. 3 microns. Note: its capacity size ... Is not limited to causing unheated or intermittent heating of alarms. And it's explosive. The above is a preliminary maintenance step for repairing the electromagnetic furnaces, indicating that the light is on, alerting, or disrupting heating (and, of course, there are a number of reasons for this failure, without going into detail)。
And this is where you're going with the maintenance of the electromagnetic furnace, which is practical, and it applies to a variety of machine types. I'll write it down and publish it. It is hoped that there will be some inspiration and help for starters in the maintenance of electromagnetic furnaces。
