HV in a laptop???

H

hannobisschoff@gmail.com

Member

• Jun 15, 2011

• #1

Hi, as I was hacking this laptop (basically just an euphemism for ripping it apart).
I saw this "High Voltage" sign on the back of the LCD. Can someone please explain to me what this is doing in a laptop?

 

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H

hannobisschoff@gmail.com

Member

• Jun 15, 2011

• #2

Note the "cold cathode fluorescent lamps"
Whatever that might be.

 

K

KeepItSimpleStupid

Well-Known Member

Most Helpful Member

• Jun 15, 2011

• #3

Cold cathode = no filament. Florescent = a little mercury in a tube and a phosphor and you guesed it, a high voltage. About 300 V or so, I believe.

It's the backlight for the LCD screen. Without the light, the screen would be very dark.

New technology is LED backlit.

 

H

hannobisschoff@gmail.com

Member

• Jun 15, 2011

• #4

Yup, forgot to mention this is an old laptop.
LED backlit nowadays hey? So how do they generate the 300v. With a transformer, or charge pump?

 

Noggin

Member

• Jun 15, 2011

• #5

Transformer based, and fairly low current.

Edit: Post 556

 

Last edited: Jun 15, 2011

H

hannobisschoff@gmail.com

Member

• Jun 15, 2011

• #6

Is the HV DC or AC?

 

Reloadron

Well-Known Member

Most Helpful Member

• Jun 15, 2011

• #7

They use an inverter. So as you hack away, note the backlight(s) and follow the wires. You should find the inverter power supply that drives them.

AC and give this a read.


Ron

 

Last edited: Jun 15, 2011

K

KeepItSimpleStupid

Well-Known Member

Most Helpful Member

• Jun 15, 2011

• #8

**broken link removed**

 

H

hannobisschoff@gmail.com

Member

• Jun 15, 2011

• #9

Thanks guys. Usually when I'm busy with my "HACK ATTACK" I'm in such an euphoric haste, that I tend to miss these things.
As for now, I'll stop the hacking, and go to bed, since it's 2:30 in the morning in my part of the world. Cheers

Hanno