[ale] fried innards

[Calvin Harrigan]

I was just saying that kind of current draw is usually caught by over 
current protection circuits which would allow the rated current plus a 
little overhead.  I didn't expect the main fuse to pop. It's impossible 
to say how much current actually flowed, so...

On 8/6/2013 3:39 PM, Alex Carver wrote:
> It's not exactly the right thing to say safety is an issue if a power
> supply delivered its maximum rating without blowing a fuse.  That's what
> you expect and that's what it is designed to do, deliver up to the max.
>   You wouldn't expect to have a wall outlet in your house claim to
> deliver 20A and then only deliver 5, right? :)
>
> I've seen this happen a few times and it was almost always a loose
> connector (or a Molex with poorly seated pins) but in one case it was a
> fine layer of dust that became moist (high humidity in the room) and
> started to conduct current.
>
> In any event, even just 20 amps into a 22 gauge wire is enough to light
> it up.  The event is self limiting, though, because the resistance of
> the wire climbs quickly which then regulates the short-circuit current.
>   So no fuses are gong to pop because the short is still within the
> operating parameters of the power supply.  The supply has no way of
> knowing the difference between a large current draw due to legitimate
> loads (hardware) versus a short.
>
> If you can find the specs on the power supply, do so and see what its
> limits are.  If not, assume the power supply sustained some permanent
> damage and replace it.
>
> On 8/6/2013 12:28, Sean Kilpatrick wrote:
>> I no longer remember the brand of power supply, but I do find it
>> interesting that no brand name or electrical details are visible on the
>> surfaces of the PSU that I can see.
>>
>> Looking at the charred remains of the fried plug, I can see that both
>> ground wires popped out of the plug and the 12 volt yellow wire has its
>> insulation burned off for nearly 2 inches.  Yet the PSU fuse did not
>> trip.
>>
>> Sean
>>
>> --------------------------------------------------------------------------------
>>
>>
>> On Tuesday, August 06, 2013 03:11:21 pm Calvin Harrigan wrote:
>>> On 8/6/2013 2:54 PM, Sean Kilpatrick wrote:
>>>> Power supply is a replacement. Got burned years ago buy a cheap power
>>>> supply. I no longer remember the specs on this one, but it is AT
>>>> LEAST 30% larger than necessary.
>>>>
>>>> BUT, the box itself is more than 7 years old, and the mobo/cpu and
>>>> power supply are five years old, as are the RAID-1 drives.
>>>>
>>>> Everything else seems to be working as it should. I'm thinking this
>>>> may be the "handwriting on the wall." If that's the case, I'd better
>>>> go get a lottery ticket! :)
>>>>
>>>> Sean
>>>
>>> <snip>
>>> Like someone mentioned above, it was probably a loose/bad connection,
>>> but still it's very odd.  Trying to imagine what could go short in A
>>> DVD-ROM to allow that kind of current draw.  Filter Caps? reverse
>>> voltage protection Diode?  If all is working as it was sans the DVD,
>>> you're probably OK.  But for my information, what brand is the power
>>> supply?
>>>
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>>
>>
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>
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