# Spock's Law



## Carl Spock (Sep 3, 2004)

I long ago gave up trying to be famous in my field, which is consumer electronics. But if I ever am, it will be because of an observation I've made on how things break. This observation has caused a belief I've held for years, and that has been backed up again and again by experience. I have never seen it expressed by anyone else, so to my best knowledge, this is original. Let's call it Spock's Law.

*Spock's Law: When something breaks, suspect the least expensive component first.*

If your satellite system stops working, it's a connector or a cable that's the most likely cause. Or it's an inexpensive multiswitch. It's least likely to be the expensive receiver.

This also works within a component. If your DVR goes down, it is most likely something inexpensive and mechanical (it's not original to me that mechanical pieces break more often than electronic ones). Even if it is a relatively expensive part within the component, like the hard drive, it is something cheap like a bearing that goes bad.

Spock's Law is not limited to electronics. If your vacuum cleaner stops working, it's probably a filter that's plugged. Problems with your car are usually bearings, gaskets, hoses and stuff like that. Rarely does the main computer die. It even works with expensive cars. For all of you who have problems with your Mercedes, it's not with the drive train, which is practically bullet proof. It's the switch that rolls us the passenger window up and down that goes bad. Now, with a Mercedes, it's probably $187 to replace that switch, but you knew that already.

It is only an advisory. Spock's Law says the most likely piece to be defective is a cheap one. It is not absolute. Your plasma TV can and will break (see my rant that all machines wear out), but if you lose your picture, the first things to check are your connectors.

Spock's Law applies to hardware only. Software is something different. I think it obeys the laws of the Devil.

In a recent thread, a guy believes his replacement DVR is bad. I'm trying to convince him it's more likely an optical cable or the optical connection itself. That's Spock's Law. I don't think I'm succeeding, but my forehead is already flat from slamming against brick walls.


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## Stuart Sweet (Jun 19, 2006)

If I may add a corollary, which should properly be called Vincent's Law, in honor of the man who taught it to me:

*Bad cables comprise 90% of the problems with the equipment.*

Same idea.


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## hdtvfan0001 (Jul 28, 2004)

My umpteen years of experience have shown that *both* the aforementinoed laws are correct.


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## DogLover (Mar 19, 2007)

I like this. It hold true in my experience as well. Another corollary that works for both hardware and software is that *whatever was last changed, is the most likely cause of a new problem.* The trick is to determine everything that has changed.

For example if you replace a DVR, you have changed that component, every cable that is connected to it, and potentially other equipment that could have been accidentally bumped or changed at the same time. (Since most of us have equipment that is in less than ideal spots for accessing the back of equipment where most of the connections are made, it is easy to affect things other than what we are directly working on.)

This would seem obvious for software changes as well. However, I can't count the number of times I heard a programmer say "My change couldn't have caused that problem." Ninety-nine times out of 100, it is that changed that caused the problem.


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## morphy (Jun 5, 2007)

In my profession I'm more familiar with Scotty's Rule: Always overestimate the time required to solve a problem, in order to become a miracle worker when it does not take as long.


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## r0b0tic (Dec 18, 2007)

Inexpensive broken parts fall into 2 categories:
1) Extremely difficult to repair or replace
2) Can not be replaced without breaking more expensive adjacent parts (the cascade effect)


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## Carl Spock (Sep 3, 2004)

Don't remind me of the Bang & Olufsen all-in-one system I was driving back from service in 1978. I had to stop suddenly, it slid, and broke one of its control sliders. In the process of fixing that, I noticed the turntable on top wasn't working right. I propped the system open with a screwdriver, cycling the turntable to see what was wrong. Reaching for a suspect part, I knocked the screwdriver down and its shank landed against the output transistors, blowing them up. I'd gone from a working piece to one that was trashed cosmetically, mechanically and electrically in less than an hour. Swift.  

I took it to a buddy who had a B&O service center (I couldn't admit such abject stupidity to my store's own) and he fixed it for me for about $120. I paid that bill, gratefully.

Back on topic: the most likely piece to fail in a satellite system is the F-connector. Compression connectors have made this less so, but still, it is the trouble point.


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## Richard King (Mar 25, 2002)

> I'd gone from a working piece to one that was trashed cosmetically, mechanically and electrically in less than an hour. Swift.


Ah, another story that should have been caught on video tape.


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## hdtvfan0001 (Jul 28, 2004)

morphy said:


> In my profession I'm more familiar with Scotty's Rule: Always overestimate the time required to solve a problem, in order to become a miracle worker when it does not take as long.


That explains why many of my project folks come back with exhorbitent estimates.


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## FTA Michael (Jul 21, 2002)

DogLover said:


> I can't count the number of times I heard a programmer say "My change couldn't have caused that problem." Ninety-nine times out of 100, it is that changed that caused the problem.


Ninety of those times, the change exposed a flaw in previous programming, and _that_ was what malfunctioned. So the change itself was okay, but implementing it caused a breakdown. Which is why there's a testing department.


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## Ray_Clum (Apr 22, 2002)

These, of course, are primarily corollaries of the original Murphy's law:

What can go wrong, will go wrong, at the worst possible moment and be totally unrepairable.


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