Lesson in dust cleaning

[c_hegge]

So, this came my way recently. A Thermal Master 420W PSU, made by Sun Pro, but it was totally packed with dust.





As you can see, there is a fair amount of dust packed around the switching transistors.

Rather than cleaning and refurbishing the PSU, I decided to use it for an experiment - Could this kind of thing really start a fire? I've long suspected that an exploding transistor could, but never had the chance to prove it. So, I loaded it up to 350W on the tester. This load is actually safe normally (I have load tested a similar PSU before, which managed 350W OK).

After less than a minute, there was a massive explosion, and flames shot out the back grille. The PSU stayed on fire for several seconds...


...which melted the wires on the voltage switch and charred the EMI filter coil somewhat,



melted the airflow baffle,



and gave us some pretty nasty charring on the heat sink. Both of the switchers were just about blown in half.

Thankfully, the fire did self-extinguish after a few seconds, but I certainly wouldn't count on that happening every time, if there was a little more dust in the PSU than what I had here.

[cheapie]

Re: Lesson in dust cleaning

Wow. I had an old Bestec (ATX-250-12E, yes, it fried the motherboard) that was packed. I would have sent it to you if you were closer.

[Per Hansson]

Re: Lesson in dust cleaning

You should have filmed it, much more entertaining

[shovenose]

Re: Lesson in dust cleaning

^this

[Pentium4]

Re: Lesson in dust cleaning

That is scary, knowing how many cheap PSU's there are out there and the average person seems to NEVER dust their computer

[c_hegge]

Re: Lesson in dust cleaning

You should have filmed it, much more entertaining

I thought I did. I only realised my camera wasn't recording after. I mustn't have hit the button hard enough. I will probably repeat this experiment in the future, once I find another suitable candidate.

[ChaosLegionnaire]

Re: Lesson in dust cleaning

the thing i found funny about this was that the psu was called a thermal master and made by sun pro. it certainly lives up to its names and shone and burned brightly like the sun!

anyway, an excellent experiment TS! i am far too afraid to try something like this. i hope u tried this in an outdoor shed, testing sandbox or something lol...

[momaka]

Re: Lesson in dust cleaning

Very interesting. I know dust lint is flammable but never thought it would ignite from a component shorting out.

I wonder if anyone is willing to try the same experiment with a desktop PC full of dust. I bet the results would be similar if not worse. I've seen some really REALLY dusty cases before. Could probably sustain the fire inside for a good half minute or so.

[999999999]

Re: Lesson in dust cleaning

Lots of people have PSU dustier than that inside before it fails. The metal case tends to do a pretty good job of containing a fire till it goes out.

[c_hegge]

Re: Lesson in dust cleaning

I am probably going to repeat this experiment with a Hairong 430W PSU, and I'll add some extra lint and dust to it, and make sure to video it

the thing i found funny about this was that the psu was called a thermal master and made by sun pro. it certainly lives up to its names and shone and burned brightly like the sun!

anyway, an excellent experiment TS! i am far too afraid to try something like this. i hope u tried this in an outdoor shed, testing sandbox or something lol...

Hahahahahaa Yes, I did it outside.

Lots of people have PSU dustier than that inside before it fails. The metal case tends to do a pretty good job of containing a fire till it goes out.

Yes, until the flames start coming out the rear grille. If you had your PC in a wooden cabinet, then you could be in real trouble.

[999999999]

Re: Lesson in dust cleaning

^ Show an incident when this actually happened and it ignited something. There's always those one chance in an billion events, but there are a billion PCs so where is that one event?

I like destructive experiments as much as the next guy but for best results you should add an accelerant.

[cheapie]

Re: Lesson in dust cleaning

I like destructive experiments as much as the next guy but for best results you should add an accelerant.

Like a water cooling system with gasoline as the coolant?

[999999999]

Re: Lesson in dust cleaning

^ Might be enough if it had a sprinkler head on it to create a fine mist inside the case, but I don't think a sealed system with gas in it would be enough.

[c_hegge]

Re: Lesson in dust cleaning

I decided to repeat this experiment, as I got my hands on another identical PSU which was destined for the scrap heap. This time around, I added the dust. I used a lot - as bad as the worst I've ever seen before.



Yup, that's packed with dust. That's about as bad as I've ever seen it get. Let's load her up to 350W and see what happens...



The fire really took hold this time. That looks pretty burned.



Bits of melted plastic (presumably from the fan) on the test bench



Um, yeah. That's wrecked. A re-lube isn't going to fix this fan



It's surprising just how much of that didn't burn (and how much of it you don't need for a fire to take hold)

The only reason it isn't worse than that is because I put the fire out after just over a minute (the smoke would have annoyed the neighbours if I had let it burn out). If I hadn't done so, I think there would be nothing but charcoal left.

[goontron]

Re: Lesson in dust cleaning

^ YOU STILL DIDN'T GET IT ON VIDEO!!!! please get the next on on video!

[c_hegge]

Re: Lesson in dust cleaning

^
Yes, I did. I'll upload it shortly

[goontron]

Re: Lesson in dust cleaning

^ YAY! sorry for shouting

[c_hegge]

Re: Lesson in dust cleaning

https://www.youtube.com/watch?v=XTKCPMgn8J4

There ya go (about 2 mins in)

[shovenose]

Re: Lesson in dust cleaning

Any chance you could start making your videos in 1080P HD?

[c_hegge]

Re: Lesson in dust cleaning

No. My camera only does 720p