What to do if You hear explosion sound from computer switching power supply box

That would be the sound of a capacitor letting it charge out into the air.

You can see pictures of bulging and leaking capacitors here:

http://www.ryansccs.com/power-supply-failure.html

It could be a capacitor, or like what happened to me, a voltage spike or surge causes the VDR (voltage dependant resistors) or MOV's to explode. Sparks came out of the back, but the PC still worked OK.

I replaced the PSU, they are chap enough to replace, and are not worth repairing for a PC. Specialised PSU's are worth fixing though, or for industry like the one I show on my hubbpage.

These circular devices look like capacitors, and they are connected across the mains.

If too high a voltage goes in, these absorb the energy over a certain voltage above the mains voltage, but if too much energy goes in, the rating is exceeded, and they go pop. Sometimes the fuse will blow as well, cutting off the appliance.

Lightning storms etc, can cause these spikes and surges, as well as changes in load on the mains grid system.

If a capacitor has blown, it has probably got old, dry, and overheated, or some other component failure has caused it to have excess voltage across it, and it has blown up due to this.

The gasses swell the case of the capacitor inside, and it explodes, giving of vapour, and the casing splits open.

Sometimes a failed PSU can ruin your motherboard, and overvolt the capacitors on it, and ruin the ASIC chipset.

It is best to check and replace your motherboard if this has happened.

The 5V rail fails on a computer PSU, because this is on standby on new computers, waiting for the on switch to wake the rest of it up.

Switch of your PC at night, fit a time switch for the deep of the night when not in use, or use a standby saver to remove the power when you switch off at night.

(ebay for those)

Hope it helps here,

Mark

generally this sounds like something has sparked and causes a mini explosion sound, and hopefully everything else is working and you will just have to replace your power supply.

remember to tie up power supply cables that aren't being used so they dont make contact with your metal case and cause sparks

send me u mobel number if u will be my friend

First and Formost,

Unplug your power cable from wall to the comptuer to avoid further damages.

Then replace your Power supply Unit.