[ale] Pictures of the culprit (was OT: Diagnosing HW problem)

Jeff Hubbs hbbs at comcast.net
Tue Jun 14 22:53:10 EDT 2005


I think that's either a regulator IC or a power transistor.

Jeff

On Tue, 2005-06-14 at 22:16 -0400, James P. Kinney III wrote:
> WooHoo! Nice pics of dead hardware!
> 
> That stuff is power component devices. Likely a capacitor used to trim the
> power to the CPU (they are often the largest things on the board).
> 
> If I recall, you had some power supply issues with this rig earlier. It is
> likely that the PS was failing and cracked/nearly blew the case open on
> the cap. The new PS is fine but the on-rush of current was the end of the
> part.
> 
> The _bad_ news is you are likely not going to get a new mobo on a warranty
> return. Unless the board was super expensive it's not worth a claim to
> insurance.
> 
> As to tv tuner cable being the source of the power spike, Yes! It CAN happen.
> 
> My first system that I bought myself was toasted during a lightning strike
> that was too close to the phone line. The box was OFF and UNPLUGGED but
> the phone line to the modem was still in and the modem was serial port
> cabled to the box. Chips were exploded in the modem, the mother board had
> burn marks all over it between traces and the hard drive heads were welded
> to the drive.
> 
> More recently, lightning hit a tree outside my office (~5' from where I
> was standing!!). The EMP wave trashed all sorts of things. It induced a
> high voltage on wires like the Cat5e all over the office. That destroyed
> NICs and routers and switches and (I'm convinced but lacking direct
> evidence) the untimely dead of motherboard and hard drive 2 days later.
> I'll never forget seeing a pair of flourescent light tubes that were still
> in the plastic wrap leaning against the wall lit up like they were running
> at 500W instead of 35W! That was what let me figure out that the EMP
> induced an electric field over 5kV! All of my surge protectors were
> unphased. Even the first line of one shot wall wart protectors.
> 
> So a very nearby lightning show even with great surge protection can wreak
> havoc.
> 
> > Guys,
> >
> > After examining the mb with a flashlight, I found the culprit.
> >
> > See:
> >
> > http://www.sourceillustrated.com/mb_1.jpg
> > http://www.sourceillustrated.com/mb_2.jpg
> >
> > Ok...now for real technical lingo here...
> >
> > Of the four square thingies with the silver circle in the middle, notice
> > one is most definitely *not* like the other.  First, what is this fried
> > and charred thingie?  Second, does this look like it may have resulted
> > from a lightning strike (we had some good ones here this weekend).  I have
> > the box behind a good surge protector and UPS, but like a DAU I have cable
> > running directly into a tv tuner card with no surge protection, so I'm
> > wondering if that may have provided a clear path.
> >
> > Interested in learning your thoughts.  Thanks again for the help!
> >
> > John
> >
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> >
> 
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