I removed AG from LCD Acer AL1516 then I got the negative image on.
Please help, if anyone know why.
Thanks in advance.

Negative image? Meaning white->black, black->white, red->cyan, green->magenta, blue->yellow? That is, complementary colors?

Maybe a picture of the LCD would help. And also of the AG you removed... just in case you took the polarizer with it.

You need to be more descriptive. If you have a negative image, your polariser is oriented wrong or you don't have a connector in right. If you don't have any image, you pulled up your polariser.

I've removed AG more than 20 LCD. But this one, I have no idea why. I recheck all of the connector. nothing wrong. Thank you everyone.

Yes,it is.
I'm sure that it isn't polarizer. just AG

Well, it sounds like something is backwards. See, to get complementary colors you have to send the opposite values (or, values from the opposite end of the range. For instance, a pure red value is represented as (255,0,0) in RGB values. To get the complementary color cyan, the color value is (0,255,255). So, in red the values are from zero, while in cyan the values are from the max of 255.

If you're absolutely sure that the connectors are correct, then I would check that you have a proper ground. I'm thinking that maybe the values are working from ground as a reference, but the "ground" isn't really neutral.

Or I could be making this up as I go along.

Thank you AP.
I will try that. But I'm not sure how I can connect the ground , since I haven't noticed before I stripped LCD. I've never been thinking about the ground of LCD.