1. What should I do if the computer case leaks electricity?
When we find electricity leakage, we must first confirm whether the electrical plug-in board we use has a good grounding design. If it is not replaced immediately (including household appliances), (the more common in-wall electrical socket), with good grounding, even if leakage occurs, damage and loss can be minimized.
Open the case and check the wiring inside and outside the case to see if the insulation package is damaged and if the metal parts of the wires are damaged. If they come into contact with other accessories and the case, replace them immediately. Or directly choose wires wrapped with nylon mesh, which can also provide better insulation effect.
The problem of grounding of wires and sockets has been ruled out. In view of the previous analysis, the biggest culprit of chassis leakage is the power supply. Let’s start from the power supply, disassemble the power supply and see if the EMI circuit of the power supply is Completeness, whether the plastic film or mica sheet between the spacer component and the metal casing of the power supply has lost its insulating effect, and whether the internal capacitors of the power supply have exploded. If there is a problem, you can make a high-temperature resistant plastic film yourself. , form a shielding barrier between the component and the power supply casing. If the problem cannot be solved, replace the power supply immediately. Check the motherboard and graphics card inside the chassis, and check whether the PCB board is deformed or otherwise in direct contact with the chassis.
It is best to use a minimized system for inspection. On the one hand, it makes the platform simpler and easier to judge, and on the other hand, it can avoid unnecessary damage during the testing of hard drives and other accessories. Check the case itself. Behind the front panel of the general case, there is a PCB circuit board that connects the motherboard audio, signals, switches, and USB extensions. We also need to check the circuit board and the wires connected to the circuit board for insulation failure and components. If there is a short circuit or burnout, it can be repaired or replaced with the help of simple electrician common sense and electrician tools.
Of course, we can also make a full range of judgments and finally find out the problem by placing the chassis in a drier location (for example, if the original location is relatively humid, it may easily cause a short circuit in the wires), replacing the insulated shoes at the bottom, etc. The culprit of leakage.
2. What to do if the computer host leaks electricity
First! You have to judge whether it is leakage or static electricity. The way to judge is to connect one end of a wire to a water pipe before touching the computer, and then connect the other end to the computer casing. Then touch it with your hand. If there is nothing wrong, it is static electricity. Otherwise, It's just leakage. If there's a leakage, you can't deal with it. You'd better go get it repaired!
If it is static electricity, check to see if your chassis plug is a three-pin plug. If so, it is probably because the ground wire of your home is not connected properly. In this case, you have two options: 1. Find Call an electrician to check whether the ground wire is not properly installed in your home wiring or whether the ground wire connector in the socket is loose (if you are familiar with the wiring, this is not a problem) 2. Find a wire and screw it on the screw on the back of the chassis, and connect the other end to the water pipe ( The water pipe is well grounded. If you only connect it to the ground or the window, the effect will not be good. There may be static electricity when it is dry.)
2: The grounding wires are all good. I also touch the case with my shoes on
Static electricity is generated because of the difference in electric potential, which is the same as the difference in water pressure. The reason why the water from the kettle is poured into the cup is because of the difference in water pressure, and it has nothing to do with whether the cup has a bottom (wearing shoes) or not.
3: My monitor will not leak electricity for the time being.
That’s because the monitor casing is not prone to static electricity accumulation.
4: Also, when I inserted the USB flash drive, the metal part of the USB flash drive was charged. . .
Of course, the metal part will be connected to the metal part of the chassis.
Let me sort it out again and answer these.
A: How did you deal with such leakage situations in the past? Is it better to use a metal wire for grounding or to replace the power supply directly?
My home is directly connected to the ground wire from the power supply bureau. During the renovation, all sockets, lights, and electrical appliances were grounded, so this phenomenon does not and has never happened.
B: Can I put the chassis directly on the ground without using metal wires? (I live upstairs, and no matter how much I dig, it’s still cement.)
No, it’s not very effective when it’s dry. I guess your cement floor can’t be very wet either ^_^
C : Will the leakage of electricity from the chassis cause leakage of electricity from my monitor?
No, the cover of the monitor is made of plastic! There may be static electricity inside
3. What to do if the desktop computer host leaks electricity
There are many reasons for chassis leakage, but the problems are mainly concentrated in a few places. We investigate these places one by one, and I believe it is not difficult to analyze the exact reasons.
1. Electricity leakage from external factors
When using a computer, you feel that the chassis is leaking. In fact, there are some objective reasons from the outside, such as static electricity on your body or touching the chassis. Some electrical equipment will cause leakage. It is relatively simple to troubleshoot such a situation. You only need to touch metal objects and remove the charged equipment to solve the problem. Let’s talk about some potential leakage risks that are really hidden inside the chassis.
2. Leakage due to internal reasons in the platform
The first is the power supply. It is the accessory that is most likely to cause leakage in the chassis, because the components inside the power supply are large and the space is It is relatively narrow, so if the manufacturer does not pass the component layout or welding process and allows the internal components to come into contact with the power supply casing, the power supply itself will leak electricity, and the power supply and the chassis must be in close contact, so there will be signs of chassis leakage. phenomenon. In fact, manufacturers often use plastic film or mica sheets to block the power supply inside the power supply close to the casing. Some wires and components will even be insulated and wrapped accordingly. However, if the power supply is used excessively or encounters severe weather conditions such as humidity, The climate environment destroys the good "environment" inside the power supply itself, and leakage will also occur accordingly.
At the same time, high-quality power supplies from well-known manufacturers will have an EMI circuit laid out when the mains power enters the power supply. In addition to better ensuring the "purity" of the mains power entering the power supply, the EMI circuit , and will also have a good effect in preventing leakage, because the Y capacitor in the EMI circuit is a leakage capacitor. When the computer is powered on, it will conduct the electromagnetic radiation generated by the electronic components to the ground through the ground wire, reducing the If the inferior power supply omits such a complete EMI circuit, the probability of leakage will be greatly increased.
The wiring inside and outside the platform chassis is also the culprit that is prone to leakage. For example, the power cord required to power various accessories, or the SATA data cable, or the power cord connected to the electrical socket outside the chassis has become damaged due to long-term use, destroying the original shielding protection measures. After these damages, *** The metal wire part just touches the chassis, which also makes people feel like there is leakage of electricity.
In addition, the board card will also produce leakage. During the application process, the motherboard, graphics card, etc. may have to load a large and heavy radiator, causing the PCB to deform. After deformation, it will cause If a component comes into contact with the chassis, causing leakage, or some capacitors on the board are exploded and damaged, the electrolyte flowing out will form a conductive strip, leading to leakage on the chassis.
3. Lack of grounding is the biggest mistake
In fact, every accessory inside the platform may cause leakage, causing the outside of the platform to touch the chassis, and some Feeling of leakage. In fact, this leakage situation also comes from the electrical plug-in board used by the user, which does not have a perfect grounding design, resulting in the leakage effect generated by the internal components of the platform. The leakage cannot be guided to the earth through grounding, reducing the risk of leakage.
4. The harm caused by electric leakage
Although after the current conversion of the power supply, the low-voltage electricity required for various accessories inside the platform will theoretically not Exceeding 12V is within the safe power range that humans and the earth can withstand.
Only long-term contact will cause adverse reactions to nerves, physiology, etc., but these are just normal situations. If there are certain components inside the accessories in the platform or a short circuit occurs between components, then the short circuit will When the component itself reaches the chassis, a very large voltage and current will accumulate in an instant. Such leakage may be life-threatening to the human body. Therefore, when we find that the chassis is leaking, we must immediately find ways to investigate to prevent the leakage from getting worse. The more severe the accumulation, the more likely it is the users themselves who will be harmed in the end.
4. Desktop chassis leakage
Chassis leakage is induced static electricity. Although the voltage is high, the current is very small. Generally, there is no harm to people if they touch it.
Touching the monitor with your hands is an example. Although the surface of the monitor has a lot of static electricity, there is even a tiny discharge sound of "pop" when you touch it with your hands, but you don't feel it with your hands. Therefore, if the casing is electrified and there is an obvious tingling sensation when touched, this situation may be a leakage.
When encountering this situation, you should start by preventing leakage. The author has summarized three methods in practice for your reference: ① The simplest method is to exchange the positions of the live wire and the neutral wire (such as turning the two-phase plug 180 degrees and then inserting it into the socket). This method is generally very effective.
Because some electrical appliances must follow the principle of "zero on the left and fire on the right", leakage from the casing will occur if they are plugged in reversely. Especially computers and printers must strictly follow this principle.
The author once encountered this situation. After the plug was inserted backwards, both the computer host and the printer were charged. I did not dare to touch the metal casing with my hands. I used an electric pen to test. The neon bulb was very bright. Use a multimeter to test it. The voltage to ground actually reached over 160 volts. After swapping the positions of the live and neutral wires, there was no electricity at all. ②Clean the dust on the circuit board, especially the power supply motherboard.
Because if there is too much dust, it will sometimes conduct electricity (especially when it is damp). After the high-voltage and low-voltage parts are connected, the outer casing may become electrified. In this case, the dust on the circuit board should be cleaned. If the dust after getting wet is difficult to remove, clean it with anhydrous alcohol. After that, use a hair dryer to dry it to remove the moisture.
③If none of the above methods work, the most effective method is to ground the shell. By guiding this electricity to the ground, people will not be "electricized".
In fact, our computers are usually connected to multiple peripherals in daily applications, such as monitors, printers, scanners, etc., and even local area networks. As long as one device leaks electricity, then through the data cable Or network cables will string electricity to each device. Therefore, we sometimes feel that there is electricity in the computer mainframe, but it is not necessarily the computer mainframe leaking electricity. When we check, we should disconnect the connections and check one by one to find the "leakage culprit".
Electricity leakage, like static electricity, not only brings inconvenience to ourselves, but also causes certain damage to our machines. However, we must treat them differently in order to solve the problem correctly.
5. What should I do if the computer host leaks electricity?
It would be really special if the host still has power after unplugging the power supply. First of all, what you said "the plug after the host unplugs the power supply" "Still has power" means that the computer can still be used normally after unplugging the power plug of the host machine, or does it mean that the computer can still be used normally after unplugging the power plug and using a pen or multimeter to test that there is power at a certain location? It is normal to unplug and return electricity because there are many capacitors on the power supply and the motherboard that can store part of the electrical energy
The latter problem is easy to solve. If the main case case leakage is ruled out as static electricity, then it can only be the main unit. The power supply is leaking because all the electricity coming out of the power supply is DC, so it can only be caused by the leakage of the power supply itself. It is recommended to replace the power supply or repair the power supply.
Another guess is that your first problem may be caused by the second one. Basically, all problems caused by changing the power supply will be solved