Day 81

I've always been a bit curious and have wanted to see what makes something tick. This is a CD burner from one of my older computers. And no, it wasn't working before I operated on it...

The circuit board on the left in each picture handles the electronics such as how fast to spin the CD, how to move the laser assembly, how to talk to the computer via the IDE interface, and all that stuff.

The picture in the right shows the laser assembly which is just to the right of the large black wheel. The small round blue-green piece is a plastic lens that focuses the laser beam. That light shoots down on  your CD and either gets reflected back or doesn't. A clean unrecorded CD will reflect light. When "data" is written, the laser light burns a tiny pit that won't reflect light. So as the CD turns you'll get laser light reflected or not-reflected. That's the 1's and 0's of computer talk.

For those of you who remember vinyl... The laser is like the needle and the CD is like the record. Instead of the laser sitting on the record and following the grooves, the motor assembly will move the laser back and forth above the pitting in the CD. And that pitting is like the grooves cut in a record.  So I guess you could say that a CD is like a modern day record.

When you scratch a CD on the shiny side that the laser looks at, all is not lost. If you can buff it out or fill in the scratches so the laser light shines cleanly through it you can "fix" it. You can find these at the stores and if you are patient you can fix up a CD.

But don't scratch the side that has the label and picture because that is the same material that has the pitting or the real information on your CD. Scratch that and you could permanently ruin it. Hold it up to light and if you see light coming through holes in the media you have a problem.

Speaking of records, have you ever taken something like the end of a pin and used that for a needle?  I have and you can hear the actual record playing. Not loud mind you and more than likely you'll ruin the grooves and the record, but it's a fun thing to do. (Kids, go find Dad's best record and try it out...but don't tell him I told you to...that was my evil twin)

Now, if anyone is still with me, the motor is in the left picture in the lower right. It has the flat green colored wire traces going to it. The long rod sticking out to its left spins and the grooves cause the laser assembly to move back and forth as the electronics think it should.

And those four bluish rings in the corners of that rectangular assembly?  Ever hear a high speed CD make all that noise as it starts spinning fast?  You'll swear it's a jet taking off. Those blue soft rubber grommets will help dampen the vibrations. Not all of it as you can hear and feel, but it does an amazing job.Without those it could damage your CD.

I've just scratched the surface, but isn't technology amazing?  And the best thing is you don't even have to know how it works. You just put in the CD and play. Hopefully some good tunes, nice family pics or some fun game like Starcraft or some flight simulator. Or as more likely these days, something from NetFlix.