Working LCD screen not working...

I have three laptops as follows:

#1 Acer Aspire 6930 (16" widescreen)
#2 Acer Aspire 6920 (16" widescreen)
#3 Compaq Presario M2000 (15" square)

Laptop #1 is the one that I am attempting to fix, the screen only displays vertical lines. Video displays fine on external monitor. Assuming the LCD screen was bad I took the working screen from laptop #2 (exact part number) and put it in #1, same problem. Next I took the original screen from laptop #1and put it in #2, it works. Out of curiosity I take screen from laptop #3 and hook it up to #1. It works.

So to summarize. Laptop #1 will not display on either of two working LCD screens made for the laptop, but will display on LCD screen not intended for the make or model.

I have replaced the LCD cable and checked all connections mulitple times, all backlights and inverters are working fine.

What is going on? Why will laptop #1 display to one lcd but not the one made for it?

 

My question would be how did the third laptop end up with the same type of connector as the other two. Some laptops have ribbon cables, some are wired, some have plugs, and others "slide 'n' snap".

Most laptops are singular when it comes to their parts. Connecting that third one to the first one in itself is damnably odd...

 

I'm using the same LCD cable from #1 for all screens, disconnecting on the back side of the LCD not the video card.

 

Vertical lines, even in the BIOS setup or POST?

 

Vertical lines from the time the screen lights up till I turn it off.

 

Faulty inverter?

As far as I know, those aren't built into the LCD on most (if any) laptops.

 

I'm using the inverter for #1 on all three as well, it is seperate from the screens.

 

Have you tried stressing the video subsystem while having it connected to an external display? I'd be curious to see if when stressed for a period of time (a few hours at least) if you get the same lines on that external display. If so time for a new video card or possibly motherboard for the laptop. If not it could point to the inverter. You could get a new interter on somewhere like eBay swap it out.