Testing an LCD w/ AC adapter

**eag182** · 05-04-2007, 10:56 PM

I have a 7" LCD I want to test (12v/ 5W) - I would like to test this in my home. I also have an AC Adapter (120-> 12V / 0.5A) with an useless plug. Can I just cut that plug off and splice the wiring to the LCD leads? There is a white and black cable, I'm assuming black is ground and white is hot. P/V = .4 amps for the TV so I assume I'm safe - or is idea wack?

**pate60** · 05-05-2007, 02:28 AM

dude AC and DC are two different things, your monitor is DC and you can't use an AC adapter for it

**W3bMa5t3r** · 05-05-2007, 02:33 AM

Actually, the OP is partially correct. He can cut that plug off the AC->DC adapter and use it, IF he's wiring that plug to a valid 12v DC source (I.E a more powerful AC->DC adapter than the AC->DC adapter he's cannibalizing)... But to the OP, don't just guess on the polarity of the wire. Use a multimeter to check it.

**pate60** · 05-05-2007, 04:41 AM

i think i got confused.

i thought you wanted to use a AC output adapter with a DC monitor.

my bad.

**eag182** · 05-05-2007, 09:13 AM

Give me more cred lol its AC->DC and yes it's a DC TV. Any tricks I can pull w/o having a multimeter?

**DarquePervert** · 05-05-2007, 09:29 AM

You could disassemble the screen and juggle the parts, but I wouldn't recommend it.

You may be able to determine what is pos (+) and neg (-) from the markings on either the screen itself (where the power connector plugs in) or on the transformer plug itself. No guarantee, but it's worth a shot.

**eag182** · 05-05-2007, 04:58 PM

Ok. Multimeters are lame anyways. Guessing is all the rage, anyways. All the kids are doing it.

**W3bMa5t3r** · 05-05-2007, 05:00 PM

It wasn't about not giving you credit, just what you said wasn't 100% clear as to what you were asking about doing... so it's better we give a more complete/encompassing answer.... just in case

For your cable with the markings, yes, the one side with white markings 'should' be the hot, the other not. And for the screen side of things... as DP said you might see markings on the screen, or if you're up for opening the bezel and looking at the circuit board where the power jack is, there 'might' be markings next to the leads for + & -... but no guarantees. To be honest though, I'd go ahead and get a multimeter if you're gonna be doing much in this hobby. It's an indispensable tool.

Good luck either way.
Cheers, The W3bMa5t3r