How do I prove why my motherboard was damaged?

July 9, 2007 11:24 AM

How do I prove that a faulty Ebuyer power supply burnt out my motherboard?

Following on from my computer problems here here I assumed, following a talk with Asus support, that my motherboard was dead and, not wanting to waste the whole weekend, bought another one from PC World, intending to get a refund on the faulty one from Ebuyer the following week. Sadly it wasn't the Ebuyer motherboard that was faulty, but the Ebuyer power supply, which then killed my new motherboard and a graphics card I had in there too.

Ebuyer seem to be fine at the moment about replacing stuff that they supplied - but they won't refund me for the other damage that their products caused. They say that I need to get a professional report "proving" that their product caused the damage before they even contemplate it. They won't tell me where to get such a report - and I suspect that most computer stores will only be able to tell me that my motherboard and graphics card aren't working - not why they aren't! So - my questions are:

a) Are there any companies (preferably UK-based) which would do the sort of diagnosis they seem to want - and if so how much would the cost? (I have offered Ebuyer the opportunity to test the products themselves - but they refused).

b) What other options are open to me in getting this money back? It's not a huge amount of cash - but I really object to the principle of having to pay out because of their dodgy goods!

posted by prentiz to computers & internet (9 comments total)

Without telling you what proof they require, they basically have you by the nuts. I would go back to them and ask them what *type* of professional needs to create the report. I mean, you could take it to a computer store, tell them the story, and get them to write you up a letter. You could also get them to take a multimeter to the power supply, which should show some irregularities somewhere if it is, indeed, the problem. But then eBuyer could say "Yeah, that's not the type of report we need, sorry" - and they can keep doing that until you give up, unless you get a very specific definition of what type of report they need.
posted by antifuse at 12:53 PM on July 9, 2007

That sounds equivalent of "Not until you sue us" to me, and I'm not surprised.

From their perspective, their stuff failed, and instead of following their RMA procedure you decided to diagnose and repair the problem yourself, misdiagnosed it, and then damaged another vendor's part using equipment that was already known to be suspect. And now they're refusing to pay for the effects of your misdiagnosis.

DIY brings this risk, and not waiting the weekend got a little more expensive than you expected, but not waiting was your call.

(Many answers in the thread you linked to pointed at your power supply, incidentally. And Asus was right, your motherboard was dead, but you hadn't accounted for what had killed it.)
posted by mendel at 1:21 PM on July 9, 2007

However unlikely it may be, it is possible that the 1st motherboard took out the power supply, which then took out the 2nd motherboard. I don't know of anything you can do at home to prove which piece started it. I think you're lucky they are willing to give you a new power supply. Some companies wouldn't even do that.
posted by MtDewd at 1:52 PM on July 9, 2007

MtDewd - fortunately I have them by the proverbials on that one - the presumption in UK law is that if a product is reported faulty in the first 6 months that it is faulty - they have to disprove that. mendel - I know...I've just never come across a power supply that fries things before - in my previous experience they either worked or didn't work - still an expensive lesson to learn!
posted by prentiz at 2:18 PM on July 9, 2007

As an ex-tech support weenie, I can say this situation is not at all uncommon - standard policy where I worked would be to replace motherboard and power supply at the same time if there was any question as to which one caused the issue - and I saw plenty of cases where a bad PS would blow out the motherboard, which would blow out the next power supply, which would blow out various other necessary bits (usually the processor.)
posted by restless_nomad at 3:10 PM on July 9, 2007

Sadly, the cost of such a "professional" report, if actually done properly, is likely to be as much as, or close to, the value of the damaged parts. Even if it's borderline, the amount of headache and time wasted is likely to tip the scale. This is just a hazard of building machines, so you might need to get used to it. We blow bits up, we have to replace 'em. To be fair, it could even have been a power spike or something similar that caused it, and even though a good PSU should prevent that, they don't have to guarantee it's a high quality one.
posted by wackybrit at 3:17 PM on July 9, 2007

This doesn't help you right now, but for the future (and for anyone else coming across this thread):

The power supply is perhaps the most important, yet also the most overlooked, component of a computer. Not only does it need to supply clean and consistent voltages to all of the electrically fragile components in your computer, but it's also the only thing sitting between your computer's insides, and the freakishly unstable power that the outside world provides.

Never cheap out on a power supply! Buy one from a reputable brand, one known for quality power supplies. Personally, I go for Antec, but that's because they also build good cases, and I usually buy them together. Not only is a good brand less likely to fail, but if it does, it's less likely to take other components out with it.

Perhaps more important than the brand you go with, is the brand you don't go with. If you can't find favorable reviews of the brand online, why would you trust hundreds of dollars worth of computer components to it?

So, even if they replace this power supply for you, unless it's one of the "good" brands that just happened to fail (it does happen from time to time), I wouldn't use the replacement. Buy a better one, and use that instead. It's worth the money.
posted by CrayDrygu at 5:38 PM on July 9, 2007

I think mendel has the best answer to the question, as asked, but..

How do you know the power supply is faulty? If it is just by inference because other parts seem to have problems.. Well, the symptoms I'm able to piece together do not draw a clear picture.


restless_nomad: I saw plenty of cases where a bad PS would blow out the motherboard,

Can you describe an instance? For the record, here is a fairly detailed analysis of the operation of typical PC power supplies, and there really are very few mechanisms that could cause the type of cascading failure so often described. The mechanism I can see that might possibly lead to such a problem: the transformer could be miss wound and the output connectors could be miss wired (these can't happen in the field, and would be caught during final test); primary side windings could become shorted (pretty unlikely, but it could happen in the field); either the standby voltage regulator or (if it exists) the 3.3V regulator could fail short.

I don't know.. But, I do know that a lot of people worry about power supplies unnecessarily.
posted by Chuckles at 6:48 PM on July 9, 2007 [1 favorite]

Chuckles- that is a great link about power supplies.

As far as examples (though my experience is in mainframes, not PCs), I have seen lots of machines where both a PS and a logic card were damaged- sometimes obviously, sometimes not. But it's not usually easy to know which one started it. Even though these things are designed to minimize a cascading breakdown, Murphy is alive and well. Electrolytic capacitors, for instance, can leak all over everything.

If I found evidence of power damage on a card, I would usually replace both the card and the PS. (But I wasn't paying for the parts.)
posted by MtDewd at 11:34 AM on July 11, 2007