Tell something you did not know until recently...

[Externet]

Here is a start:
http://en.wikipedia.org/wiki/Capacitanc ... ronic_Disc

[Janitor Tzap]

I actually got too play around with one of these.
It was brought in for repair at the Voc-Tech that I was going too.
What a piece of junk!
We had to be Extremely Careful with the disks!
The smallest amount of dust would render the disk un-watch able.
Or the needle would be grinding against the dust in the tracks to many times.
Thus, ruining tracks on the disk.

We had in also a Pioneer Laser Disk Player.
The Laser Disk Player was fine.
But we students got to see the first signs of the dreaded "Laser Rot",
that was plaguing those early Laser Disks.

But I think the biggest strike against the too formats was that they could not record.
Something that the VCR's could, and disks weren't readily available in many Video Rental Stores.


Signed: Janitor Tzap

[haklesup]

What is laser rot.

Is it sililar to how the reflective and top coat layers on DVDs and CDs can vary in quality such that one disk amy last 100 years and another disc may turn virtually clear in 4-6 years. THe quality and types of plastics used has changed but theu don't tell you one way or the other. Laser discs came out so early, I suppose they would degrade over time too

[Janitor Tzap]

No, you got it pretty much right haklesup.

We found on those early Laser Disks.
They were at times made with defects in the coating process.
Thus, when you played the disk in the player.
The beam of the laser would degrade the coatings, the more times it was played.
Plus, it seemed once a disk started to degrade.
It didn't seem to stop degrading, even if you didn't play the disk that much.


Signed: Janitor Tzap

[Bob Scott]

Here is a start:
http://en.wikipedia.org/wiki/Capacitanc ... ronic_Disc

I remember those! The shop I worked for had the warranty repair contract for RCA Capacitive disks. All I remember is:

There was no modulation in the groove. The only purpose for the stylus and the groove was to keep the pickup "capacitor plate" positioned correctly over the track.

Our test record was "Jaws".

They were made in USA. The basic construction technique had a very different feel to it. Definitely not Japanese and not as easy to disassemble or service. It reminded me of fixing a Kenmore vacuum cleaner.

Stuff I just recently discovered? I have been researching fermentation and home-made distillation equipment design lately.
If you home brew beer, wine, or make your own alcohol, the amount of ethyl alcohol is almost equal to the amount of carbon dioxide produced. For example, 1 kilogram of glucose sugar becomes 511 grams of alcohol and 489 grams of CO2.
You can keep track of progress of fermentation by keeping a record of the weight lost by the must, mash, or wort every day.
I hope the government doesn't realise just how big the mass of CO2 is created by the booze industry or there will be a carbon tax (Yes, even more tax!) slapped onto all those beverages.

[haklesup]

disc degradation would be caused by a combination of oxygen, light (especially UV), heat and water vapor. Unless you store your discs in a dark vacuum it would occur at some rate. Clearly leaving a disc out in the open in a car or outdoors is the worst case. I've seen my share of carelessly discarded broken discs on the side of the road which have gone virtually clear.

[jwax]

More in the "Nuts & Bolts" category, but have you ever heard of "Multiple Start" threads?
http://neme-s.org/Multi_Start_Threads/m ... eading.htm
Most bottled water containers have multiple start threads on the caps so as to be removed without many rotations.
Who knew?