Snap, crackle, & pop.

[Groltz]

I received a phone call from my father today. He said that during an internet browsing session last night there was a loud crackling from the PC's case, an even louder pop, then everything died and the smell of burnt electronics filled the air.

This particular PC was built by me only about 6 months ago, it is housed in an Antec SX630II Mid-Tower that came with a Antec Smartpower 300 watt PSU.

I dragged my spare PSU over to his house and verified that it was his PSU which had died. Fortunately, it didn't kill any components when it decided to flame out.

After installing a new PSU and verifying everything was ok with the machine I opened the old PSU up for a look. Sure enough there was a nasty little scorch inside where it shorted.

Here is a picture (616KB)
Note: I cut away the large aluminum heatsink to provide a better view. That sheared piece of silver metal at the bottom of the pic is one of the legs it stood on.

 

[jtr1962]

I'm guessing by all the goop splattered everywhere one of the electrolytic or even ceramic caps got an internal short, heated up, and exploded. That probably caused R6(the big metal oxide power resistor) to overheat and burst into flames. Very common failure mode. The power supply is probably repairable fairly easily if you're handy with a soldering iron. That IC might be bad as well, or it might just look bad thanks to all the burnt matter on top. A fairly easy part to get. Mouser electronics stocks most of the SGS Thompson ICs(as indicated by the logo on top).

 

[Buck]

Nice picture Steve, sorry to read about the PSU. I had a similar situation recently where a customer had two identical cases with matching power supplies, and both failed. The second one unfortunately killed the motherboard. Your father was let off easy.

 

[Handruin]

That really stinks. Makes me worried to leave my machines running now... Does your fathers machine connect through a UPS, or some type of line protection? I'm wondering if a crappy power source caused the failure...

 

[e_dawg]

Makes me worried to leave my machines running now...

The stress of shutting down and powering up is no good either... I leave all my computers on 24/7... it's been very good to me. Nothing has died (except for a P/S fan)... not even my IDE hard drives.

 

[Mercutio]

If you leave stuff running long enough, you'll actually start fearing shutdowns, since "that's when things break".

 

[Groltz]

That really stinks. Makes me worried to leave my machines running now... Does your fathers machine connect through a UPS, or some type of line protection? I'm wondering if a crappy power source caused the failure...

He had it plugged into a fairly generic power strip/surge protector. The circuit breaker that blew was the one that is built into the wall outlet.

 

[Handruin]

If you leave stuff running long enough, you'll actually start fearing shutdowns, since "that's when things break".

Last August when I went away on vacation for a week, I feared my SCSI drives would not spin back up when I returned... They have been running for over 2 now 24/7. I know compared to many, this is not a big deal, but it still makes me worry.

 

[e_dawg]

If you leave stuff running long enough, you'll actually start fearing shutdowns, since "that's when things break".

how true

 

[Piyono]

I've blowed up many a capacitor myself (some by whoopsie and some out of mischief) and they do, indeed, let out a big enough pop to frighten the cat. Once a component goes the all bets are off as to what happens next.
From the looks of things I'd say that one of your caps or a resistor was well out of spec, and couldn't deal with an incoming spike/surge.

*poof*

JTR is probably right in that it's probably a simple repair, mechanically speaking, but I'd be weary of a blown PS only because some components may have been damaged but don't show on the surface. A faulty high-current device like a PS is not to be trusted, unless you really know what you're doing.
I, for one, do not know what I'm doing, so I'd toss the sucker and replace it post haste.


Piyono

 

[Groltz]

JTR is probably right in that it's probably a simple repair, mechanically speaking, but I'd be weary of a blown PS only because some components may have been damaged but don't show on the surface. A faulty high-current device like a PS is not to be trusted, unless you really know what you're doing.
I, for one, do not know what I'm doing, so I'd toss the sucker and replace it post haste.

Yeah, the unit was replaced the same day...Unfortunately the only source available at 7:00pm around here is Best Buy. The irony being that another Antec Smart Power PSU replaced the blown one. This time a 350 watt model was used; this unit has a pair of cooling fans instead of just one.
I've used Antec PSU's in the past and thought they were generally pretty reliable. I think this was probably just a freak occurance. BTW, voltage surges/spikes/brownouts are not common around my Pop's neighborhood. I think it was something else. The PSU didn't blow at startup, but after the machine had been in use for over an hour.

Sure I could have soldered components into the old unit but it looked like more trouble than it was worth. I have done soldering at a finer level than the PSU had in the past but just didn't feel like messing with this.

 

[jtr1962]

Sure I could have soldered components into the old unit but it looked like more trouble than it was worth. I have done soldering at a finer level than the PSU had in the past but just didn't feel like messing with this.

I could imagine that changing a keyboard port would be a PITA. One of my "tricks of the trade" is to use a good quality solder sucker(also called a solder pump). You heat the solder at the joint to be removed(sometimes you need to add a little fresh solder for good heat conduction) until it melts, press the button on the solder sucker, and most of the solder is sucked clean away. Do this for every pin and the component removes cleanly. An even faster way, especially with thru-hole ICs, is to cut away each pin with a fine cutting pliers, remove the main body of the chip, and then remove the remaining pins one at a time by heating them with the solder iron and pulling them out with a tweezer. After that clean the solder out of the holes with the solder sucker, clean the area with isopropyl alcohol, and solder in the new chip. I do 40-pin ICs in under 5 minutes with this technique. SMD components are a little trickier. Large SMD ICs require special equipment, period, but smaller ones(<24 pins) can be removed by applying liberal amounts of solder to both sides, jumping the solder iron between both to keep the two sides melted simultaneously(a lot of solder holds the heat in longer), and then prying the chip out with a tweezer once it starts to move. The trick is to slide the tweezer under the chip and apply a small amount of pressure. When everything is hot enough the chip will start to lift. Keep everything hot and continue pulling, but only gently as you risk pulling out traces(I did this before I got the technique down). After the chip is completely out clean up the blobs of solder with(you guessed it) the solder sucker, and then alcohol. Solder in the new chip. This usually requires you to hold it properly positioned over the pads with a tweezer until you get at least two pins soldered. Needless to say you need a fine tip iron and very steady hands. I can easily do the chips with 0.05" pin pitch(20 pins per inch). In fact, I've replaced hundreds of them repairing Taxicam 1500 controllers. The 32 ppi are somewhat harder, and I need to stay off coffee for 24 hours when I do the 40 ppi and 50 ppi ones. I don't think I've seen anything finer than 50 ppi. And no, I don't even use any kind of magnifying tools for this kind of work. My close up vision is great but long distance I'm like 20/200.

 

[Bozo]

Antec would probably replace that fried PS if you send it back. Most reputable companys like to have busted parts returned so they can analyze what went wrong and make corrections.

Bozo :mrgrn: