It never ceases to amaze me that my desktop computer is still running after 8 (or is it 10 
) years.
In electronics, there is something we call MTBF, or mean time between failure. It is the estimated number of hours of operation that it takes for a failure to occur in that device or component. In computers, mechanical devices such as hard disk drives, switches, etc are the worse and fail first. Then comes drivers such as the EIDE controllers and then video cards, etc. Come to think of it, I believe the HDD on my computer has been upgraded once or twice already. Anyhow, 8 - 10 years does not seem like a real long time, certainly not enough for cause of celebration. But considering that CPU's have millions of transistors embedded in them. Then add the chipset, everything on the video cards, and so on. With a computer comprised of so many components, it really IS amazing that the darn thing is still running. But my secret is that the computer is running all the time -- I never shut it down. I'll explain.......
What does this have to do with boomboxes?
Well, every component that a boombox is comprised of, whether resistors, diodes, panel lamps, leds, capacitors, transistors, IC's -- each has MTBF rating. Actually, the reliability of electronics can be computed with a formula. If a resistor has a MTBF of 100,000 hours, it seems like yipee! This thing will run forever, right? That true. Except that the reliability of the entire boombox is the product of ALL the combined components. If 1 resistor is rated to fail after 100,000 hours, a device with 2 resistors means 2 failures in 100,000 hours (or 1 failure every 50,000 hours). Well, considering that a typical medium boombox can have maybe 1,000 to 2,000 components, you can now see how the failure rate, starting at 100,000 hours drops precipitously to some much smaller number and gets progressively worse depending on how many components. The more components, the higher the failure rate of the entire product. Of course you can't just take the number of components and multiply them -- it's much more complicated than that. Each component has a different life expectancy. Some components have very long shelf life. Some such as electrolytic capacitors can wear out just sitting on the shelf. Some are more sensitive to heat than others. The actual formula for computing life expectancy is not important. What is important is that the more complicated the boombox (or electronic device), the lower the combined MTBF. BTW, the 100,000 failure rate quoted above is arbitrary and expressed merely as an example of what happens when you combine multiple components together to form a device.
So while I don't expect anyone to forego collecting Sanyo Big Bens in favor of 9915's, I offer this as interesting food for thought.
PS.. Back to the computer and why not turning it off affects product life ..... one of the causes for failure of electronics components such as IC's, transistors, resistors, etc is deterioration or breakage of lead to substrate junction (or the internal connection of the component lead within). Many factors can contribute to failure but the heating/contraction cycle is a primary cause. Each time a device is turned on, it begins to heat up. When shut down, it contracts. Over time, this heating/contraction cycle will break the connection. In fact, thermal related failure is a very common phenomenon with electronics and we even have freeze spray to help with diagnosing and pinpointing bad devices. By leaving the computer on, it remains at a very steady and constant temperature. The downside, of course, is that it wastes energy and the insides fills up with dust faster, drawn in by the PS fan drawing in dust.
Now, that I have bored you all to death, you can all go back to doing what you were doing....
) years.In electronics, there is something we call MTBF, or mean time between failure. It is the estimated number of hours of operation that it takes for a failure to occur in that device or component. In computers, mechanical devices such as hard disk drives, switches, etc are the worse and fail first. Then comes drivers such as the EIDE controllers and then video cards, etc. Come to think of it, I believe the HDD on my computer has been upgraded once or twice already. Anyhow, 8 - 10 years does not seem like a real long time, certainly not enough for cause of celebration. But considering that CPU's have millions of transistors embedded in them. Then add the chipset, everything on the video cards, and so on. With a computer comprised of so many components, it really IS amazing that the darn thing is still running. But my secret is that the computer is running all the time -- I never shut it down. I'll explain.......
What does this have to do with boomboxes?
Well, every component that a boombox is comprised of, whether resistors, diodes, panel lamps, leds, capacitors, transistors, IC's -- each has MTBF rating. Actually, the reliability of electronics can be computed with a formula. If a resistor has a MTBF of 100,000 hours, it seems like yipee! This thing will run forever, right? That true. Except that the reliability of the entire boombox is the product of ALL the combined components. If 1 resistor is rated to fail after 100,000 hours, a device with 2 resistors means 2 failures in 100,000 hours (or 1 failure every 50,000 hours). Well, considering that a typical medium boombox can have maybe 1,000 to 2,000 components, you can now see how the failure rate, starting at 100,000 hours drops precipitously to some much smaller number and gets progressively worse depending on how many components. The more components, the higher the failure rate of the entire product. Of course you can't just take the number of components and multiply them -- it's much more complicated than that. Each component has a different life expectancy. Some components have very long shelf life. Some such as electrolytic capacitors can wear out just sitting on the shelf. Some are more sensitive to heat than others. The actual formula for computing life expectancy is not important. What is important is that the more complicated the boombox (or electronic device), the lower the combined MTBF. BTW, the 100,000 failure rate quoted above is arbitrary and expressed merely as an example of what happens when you combine multiple components together to form a device.
So while I don't expect anyone to forego collecting Sanyo Big Bens in favor of 9915's, I offer this as interesting food for thought.
PS.. Back to the computer and why not turning it off affects product life ..... one of the causes for failure of electronics components such as IC's, transistors, resistors, etc is deterioration or breakage of lead to substrate junction (or the internal connection of the component lead within). Many factors can contribute to failure but the heating/contraction cycle is a primary cause. Each time a device is turned on, it begins to heat up. When shut down, it contracts. Over time, this heating/contraction cycle will break the connection. In fact, thermal related failure is a very common phenomenon with electronics and we even have freeze spray to help with diagnosing and pinpointing bad devices. By leaving the computer on, it remains at a very steady and constant temperature. The downside, of course, is that it wastes energy and the insides fills up with dust faster, drawn in by the PS fan drawing in dust.
Now, that I have bored you all to death, you can all go back to doing what you were doing....
too. Its sort of same with the engines as well 
. the temperature difference is the biggest killer.
