3400 lcd screen

A: Put simply you don't. Whilst it is possible to use a laptop screen as a monitor it takes a large cash investment and a good understanding of electronics. If you are lacking in either of these departments don't bother, buy a cheap LCD with VGA connection on eBay instead.

If you really want to know more about using a laptop display on another computer then do a search of the hacks sections with 'holy-grail' as your keyword. You can also try visiting Earth LCD for more info regarding the required convertor boards.

Here's one of the best explanations of why using a laptop LCD for a monitor is a difficult project I've seen so far, courtesy of Eudimorphodon:

Laptop displays simply don't speak the same language as CRT monitors, electrically speaking. It requires a complex wad of electronics to turn output meant for a CRT into input suitable for an LCD, and that wad of electronics is referred to as the 'controller'. You won't find a controller you can salvage in your laptop anywhere, because it 'speaks LCD' directly, and thus doesn't need one.

It's not just a matter of pasting wires together, which is what everyone wants to think. Those controllers sell for anywhere from $150 to $300, and for most installations require custom cables and power supplies which may well run you another $150.

Q: Lets say I've got this crazy idea into my head to run two LCD screens off one Powerbook - both spliced from the same feed on the motherboard. How might I go about doing that?

A: Once again it's Eudi and Dr. Bob to the rescue:

Mirroring two LCDs off a powerbook motherboard is technically an edge case which I don't believe I've seen before... Anyway.

In theory, if you had two *identical in every respect* LCDs, you could probably construct buffer circuitry to mirror the same input signal on both of them. The signals you'd have to replicate are low voltage, low power, and extremely timing-critical, so it wouldn't be easy, and it would probably involve parts not available at Radio Shack.

If the LCDs you have differ *at all* in the timings they'll accept, then it also won't work. LCD controllers have to be programmed to deal with the idiosyncracies of a given panel, which is why you can't easily just willy-nilly swap screens between laptop motherboards, and why those controller boards you buy seperately to work with eBay LCD panels are so expensive.

You would also have to provide an EDID code that would work for both displays to the host controller.