Rant Short-Circuits on your experiments...

[Dig Gil]

I need to express this big annoyance out. Really.
I've been working in high voltage experiments for a year or so. I've then been designing my own model of a so called "Lifter", or "Electrokinetic apparatus" as I like to call it. It will be used to demonstrate new technology in my town (though this apparatus exist since the 60's) and to later improve and make it useful.
But I haven't got any high voltage source available so I hacked an old television.

Before yesterday my own design worked like wonder! The problem is that it flew in such way (I need to fix that) that the ground and feeding wires touched causing a short circuit.

I've changed the fuse, but that fuse blew again (luck I didn't used a clip instead like once I did). There seems that something inside the television is different from what it was when the first fuse burnt... So bad I've never read books about television sets I'll need someone else to repair that for me.

 

[Artlav]

Try something less dangerous then - i used the innards of a taser to power a tesla coil and a lifter, it's about enough if you're not too ambitious, and is designed to survive a short.

 

[Eagle]

Replace it with a 'new' old tv?

Either that or get a multimeter and test the components of the tv (unplugged) to make sure they still have the electric properties each should.

 

[Dig Gil]

Sometimes I feel like in a underdeveloped country...
In a college near me this was also tried out some months ago and even the teacher hadn't access to a high voltage source... Now a Taser? Anyway, where did you got that?!:blink:

Replace it with a 'new' old tv?

Well, I admit my dumbness when I first tried with a CTR computer monitor and the connections I made inside it were plain copper. :siffle:"Ten Ways to Melt a Transformer".
This time it was an actual accident, I didn't expected it to work so well.

Either that or get a multimeter and test the components of the tv (unplugged) to make sure they still have the electric properties each should.

I know I may do that, but I haven't got any schematics, plans or diagrams even. Doing it that way with all parts of the boards and components may take a bit to much (have you heard about reverse-engineering?).

 

[Notebook]

Be very carefull with what you are doing. If you have no experience of TV EHT circuits, then leave it alone till you can find someone to help you. I worked on bench maintenance for 20+ years, and I wouldn't take the back off a set now, if I was on my own.
They have lethal voltages inside, and one mistake is fatal.

Depending on the age of the set, the EHT would most likely come from a Switched Mode Power Supply
http://en.wikipedia.org/wiki/Switched-mode_power_supply

Very dangerous as they rectify the mains, and don't have an isolating transformer. I'm biased as I got a "belt" from one of these, that didn't have the discharge resistor fitted across the main capacitor. Luckily I wasn't working on my own.

Take care, N.

 

[Brycesv1]

yeah nothing says pwnd like working on an old TV and suddenly waking up in the hospital

 

[Dig Gil]

The trick is using shoes and one hand at the time.

 

[Eagle]

I know I may do that, but I haven't got any schematics, plans or diagrams even. Doing it that way with all parts of the boards and components may take a bit to much (have you heard about reverse-engineering?).

A good number of the parts will have their model number printed on them. Just search for either the tv model number or the numbers of the parts to find out what you need to know.

We had a problem when we were setting up a computer that had problems with almost every driver. We actually opened the case, and looked up the model numbers on the chip to find out what we needed. Not the most efficient method, but it works.

 

[Notebook]

To Dig_Gil

If you are interested in generating high voltage safely, there is a way of doing it.
Use a HT coil from a car engine.
That can produce several kilovolts from a 12V source.
The important thing is you don't use domestic mains voltage!

If you can find a HT coil from a car scrapyard, it will have three terminals, two low tension, and one high tension, Looks a bit like this:
http://i89.photobucket.com/albums/k207/Notebook_04/1219963894_large.jpg

This is basically a transformer, and if you just connect your 12V source across the low tension terminals, you will generate some voltage at the HT terminal.

As its a transformer, it will only generate that voltage when the current is interupted, so you have to physicaly connect and disconect the circuit.

N.

 

[Dig Gil]

humm... never though about that. I'll research, good point.

 

[Notebook]

Nice little animation and schematic here:

http://www.magnet.fsu.edu/education/tutorials/java/ignitioncoil/index.html

Don't know why they have took one end of the spark gap to a "pseudo Earth" though? It should go to the -ve battery terminal.

N.