Computer starts smoking when plugged into power

I was trying to power on a Dell Dimension 8200 . I plugged it in to an outlet and pressed the power(outlet , that is) . Immediately there was a large BANG! and the computer started smoking . What could be the problem ? This computer is from 2002 and hasn't been used since 2010 .

3 Answers

Your Power supply is probably fried. Depending on the unit, there are ways to test it though. I know on most Antec models, you can run what's called the paper clip test where you more or less run a loop using a paperclip.

1. Disconnect your power supply from your motherboard if you have not already.
2. Flip the switch on the back of your power supply to the off position "0"
3. On the 24 Pin connector locate the green wire** going into pin 16
4. Insert one end of the paperclip into the pin 16
5. Insert the other end of the paper clip into pin 17 that has a black wire going into it. (you can also plug it in on any of the black ground wires)
6. Flip the switch on your power supply to the on "|" position.

Now, this can be ran with other power supplies, but you'll need to know what pins go where. I have an Antec and this is what I used to diagnose my PSU after I had a similar experience.

Now, this said, if you smell a charred smell, you're going to want to unplug it as soon as possible.

First power it off to the "O" position and then unplug it from the back and then the wall.

From there you can start unplugging it from inside. There's a bunch of things that could actually be the problem, but the simplest and easiest thing to diagnose would be the PSU.

I've had this happen before. Considering its age, it might be bad capacitors or simply some power regulator going bad. Since something went boom, things are a little easier.

Open up the system and do a visual inspection - look for scorchmarks on the motherboard or any 'can' type capacitors that have blown their top. While you are doing this, also check for bloated ones. If anything on the motherboard has blown up, you're probably best off chucking the system in a suitable disposal receptacle.

If its not the motherboard, I'd do a sniff test on the PSU (literally sniffing to see if that's an issue). Annoyingly dell has been known to do non standard PSUs so check the colours of the wires against a standard PSU if you are replacing it). @mattking's answer covers the details of that so I won't repeat that bit.

The only component that would immediately "bang" and then make smoke would be the power supply. Such a noise would usually be from a failed capacitor inside the power supply.

For safety, be sure the computer is unplugged before you open it up to service it.

There should be some obvious black marks and/or visible burnt components (likely inside the power supply) indicating what failed.

If the mother board (the large "main" circuit board) does not appear damaged then try a replacement power supply. You can find them as cheaply as $5 on eBay. Just search for " Dell Dimension 8200 power supply".