today was thundering/lightning hardcore and i turned off my sis's comp cuz of it. Unplugged the power strip. After the storm i turned the computer back on on then 2 secs later i hear a big pop sound sort of like a ballon that came from the computer.. Then a bad smell came out from the comp like a burnt plastic or something. After that pop everything worked fine for like 5 secs. I just turned it off right after then after i tried to turn it back on, the power suypply wont even turn on. I dont know about anything else. The comp is about or a lil over 3 years old along with the power dupply. What can this be???

Most likely the powersupply, thats not to say that it couldn't be anything else, but definately verify that first. From my experience with loud pops and plastic smell, 99% of the time its the principle capacitor in the powersupply. Replace that first (the powersupply being the cheapest member of the critical components). Check your board for visible damage/burns. If replacement of the powersupply still yields no results, the possibilities branch out pretty quickly from the processor to the board chipset to the ram. -Post back and let me know what it was.

I agree with alex When I was younger I use to overload capacitors until they poped. And when they do they have a plastic chemical type smell. But when it comes to computers a little static charge can damage components. Your best bet is to find a friend (or if you have one yourself) with another computer and trouble shoot each component to you weed out the problem.

I really love to spread hate and discontent among others, so let me start. C'mon guys capacitor? Let's not get technical here. In a computer power supply, the transformer steps the voltage down from AC 220/110 volts (depending on the tapping) to a lower voltage, still AC. Diodes convert the voltage from AC to DC (either full wave or half wave). Then the CAPACITOR. The rectified voltage although DC still has AC component, as demonstrated by sine wave. On upward direction, the voltage will reach its peak, but on downward direction, the voltage will be zero. This is then when the capacitor will start to discharge its stored voltage and fill the gap. The capacitor will then recharge again on the upward direction of the sine wave when the voltage is about to reach it's peak again. Therefore, it is possible to have output even with a "shot" capacitor. Nevertheless, I agree with you, it may be the power supply(75%). Remove the plug that supply the power to the motherboard. With the MOBO disconnected, turn on the switch. If the fan and power supply comes on, then your PS is good and you have a short on the Motherboard.(25%)

G'day, Was the computer working BEFORE you turned it off..ie can we establish that the lightning storm did no damage. If it did you could have failed components all over the place. If not, it looks like it might be a transient voltage that occurs when you switch something on (this has been known to happen if you run equipment for long periods and then "suddenly" turn them off, let them cool down and then switch them back on (notice how a light bulb only ever blows when you turn it on..)Transients through inductors and capacitors can be up to twice to four times the mains input. I tend to agree with the capacitor theory, since I dont think it could be the inductor, and Judge1, capacitors can fail short circuit!! The PSU of a PC is a switchmode type, therefore a failed capacitor will not filter the sinewave and thus do major damage to the motherboard components. If you cannot see any fried or blackened tracks on the mobo ( a good indication of lightning strike..)then you probably have a stuffed PSU. What to do? Well if you disconnect the motherboard the PSU might not indicate the problem because a lot of them have to be loaded before they will work correctly, and you could even blow it up this way. Look for any fuses on the PC (very good idea to put one in if you haven't) that might have blown.If I was you I would try to get a second hand, working PSU and put that in and check if all is well. If not, then you have bigger problems.. good luck, Elric

I was fishing! He he, almost good explanation on transient, or power surge, or voltage spike although I will not contend the exact value since I will have to go back to my differential equation for me to do that. I will not discuss LaPlace Transformation Theory if a simple Kirchoff's Law will do the job. You are also right, computer PS is a switching type, and yes, capacitor can be tested for open, short or leakage. You're right, it may be the fuse, although fuse inside the glass doesn't give off that kind of smell Unlike transistor, diodes, and similar component, capacitor is not a semi-conductor. It consists of two plates separated together with insulator in between (ever heard the word dielectric?) It is naturally open therefore open fault is more common than short. In order for it to do its filtering job, it needs to be connected in parallel with the output voltage(most commonly of electrolytic type). If it is open and failed to charge, then it will not filter the output voltage but there will still be an output voltage. If it is shorted which is very unlikely for a switching type PS (never heard of from any technician or companies) even on the lowest quality PS, there will be continuous flow of current through the capacitor which will cause the transformer to overload. Contrary to what you said, a power supply disconnected from the motherboard will not cause anything to blow up, unless you hook up a claymore at the end of the line. There will be no voltage going to the motherboard and PS is an idependent unit and can be tested.

G'day, Yes, I agree that we really don't need to get into differential equations, Laplace transform etc - maybe a little circuit theory. And,yes, capacitors are most likely to fail open circuit, although I just fixed a ballast/ igniter cct (400VAC) for a mate the other day-and guess what?? Yep! A shorted capacitor. My main point, however,was to try and establish if the lightning had done the damage- if it had then we are talking about very large transients and electrical activity that would defy simple, safe linear equations. Have you ever seen the ground return line of a motherboard after a lightning strike?? It's a black charred mess. Even if things still work the reliability is stuffed!! As far as the PSU goes; the earlier ones needed a load in order to maintain regulation of the voltages (12 and 5 particularly) and if they weren't then the voltage goes very high leading to the possibilty of component failure. I can point you in the direction of articles advising the use of car bulb filaments (or electric fire) to load the supply. Unlike a linear regulator, the SMPS is very dynamic and has large transient voltages. The energy is transferred between the inductor and capacitor (a tuned circuit!!) at the output, so if the capacitor goes open circuit the inductor needs to dump all that energy somewhere...which could lead to the motherboard being subjected to large transients. My point about the fuse is that, because nothing now works, it might have blown albeit later rather than sooner! We can certinly agree on one thing- mucking around with the PSU should only be done by someone who knows about such things. I stick by my first opinion; that the PSU should be replaced and the motherboard checked for erors ie no shorts, hot chips etc and the voltages checked to make sure they are a:within tolerances and b: have no nasty ac on them. Still, I'm sure between us, we can offer these unfortunate people some good advice. regards and best wishes of the season, Elric