Mother of all Computer Failures
by Anthony Bramante
14 November 2005
Though reasonably computer literate when it comes to using software and programs in daily life, I’ll admit I’m completely ignorant of what is going on behind those programs and inside my laptop. Which is probably the reason I’m so upset at what I went through two weeks ago.
I’ll save you the long version, but basically, after a lot of haranging Applecare informed me that my logic board had failed and needed to be replaced. After $330, it now has.
Though I love macs (I have a 2002 15” Ti Powerbook G4), I have to admit this is the second apple that has had a mother/logic board failure on me in the past few months (the other was the DOC Freshmen Trips computer a week prior to the arrival of the first `09’s.)
I understand when hard drives, disc drives, screens, keyboards, and operating systems fail: all have dynamic and therefore vulnerable mechanical or program-based components. Isn’t a motherboard just a large circuit board with a bunch of stuff plugged into it? So what gives? How does a motherboard fail to the point that it needs to be replaced?
Nov 15, 12:28 PM
Although mainboards don’t usually have any moving parts, they tend to be fairly fragile in a couple of ways. Particularly in laptops, the mainboard may receive a fair bit of flexion as the laptop is moved about and used. While they’re supposed to be able to take it, the repeated mechanical deformation can, on occasion, loosen solder joints or even crack traces. This was more prevalent in older mainboards, but it still happens even with newer ones. Mainboards are constructed fairly rigidly, and do not deal gracefully with being bent.
With component-built desktop systems, there is more wear and tear from the insertion and removal of cards, plugging and unplugging cables, etc. The screw-down points in the case help reduce this a bit, but there’s still a fair bit of movement that takes place as you use a board.
That, combined with the fact that most mainboards contain a lot of on-board logic (bus arbitration, bridges, clock circuitry, power management, BIOS and boot ROM support, and in some cases, built-in audio or video support), means there’s going to be a certain number of failures in the system. Sad but true. I’ve actually been impressed by the relative infrequency of such failures, given all the possible ways it could happen.
Of course, that doesn’t make it suck any less when it happens to you. My sympathies.
Nov 15, 04:25 PM
I don’t know how often this happens in the real world, but theoretically at least even the solid state components will eventually fail from voltage and temperature stresses.
There’s also the ever present, and very real danger of cosmic rays. Cosmic rays regularly strike the earth with shockingly high energy.
I think (vague memory warning) that particles with energy around 1018 eV hit once per kilometer*year. That’s not very often, but it is a lot of energy, and the frequency increases with decreasing energy. A 1018 eV particle can make an awful lot of ions in your semiconductor.
For reference, room temperature atoms have an energy of around 1/40 eV.