What is responsible for brightness control on Lenovo G570?

Question

Do it yourself

I wanted to write a post about how Lenovo "takes care" of the users of its products, but "habr is not a place for complaints." That's why I decided to ask a question to knowledgeable people.
And so we have:
a. laptop Lenovo G570 model 20079 after a warranty replacement of the matrix, which lacks a margin of brightness (you can make it too bright or too dark, no other options are given);
b. unscrupulous Service Center (SC), which made the replacement, and claims that after the laptop was taken from the SC it was dropped, which corresponds to a broken screen mount (they showed that a metal piece was broken off) and insist that it was the blow to the case that could (they do not know the reason) to damage the Motherboard, which is responsible for controlling the brightness of the screen;
in. the representative office of Lenovo in Ukraine, which does not want to assist in any way in this matter, but says "You have signed the absence of claims ...". laptop repair forum
, which was answered by only a couple of people, and I was interested in the answer “it was too lazy to flash it (matrix)” And the question is: so what is still responsible for controlling the brightness of this laptop? and what could be the reason? (I searched in Google, I can't find anything exactly in my case) PS Personally, it seems to me that they just put a defective matrix, but I can't prove it.

Answer 1

flash matrix? What is it like? What, the official problem from lenovo is declared? Why did they carry the laptop a second time? the problem was not solved?
The best way out for you is
a) to sell the laptop on the forum, to save money to buy another laptop
b) to put it too bright and reduce the brightness of the software on your computer through the video driver settings.

Answer 2

you can make it too bright or too dark, there are no other options.
How is it? Please explain in more detail.

Answer 3

I have something to do with laptop repair, SC and Lenovo in particular. However, I did not understand the essence of the malfunction from your description.
In general, the LED controller via PWM is responsible for the brightness of the matrix backlight. The base brightness level is set by the user via hotkeys. Indeed, the MP exposes information about the selected level on the control contacts of the LVDS connector. Through the cable of the same name, all data enters the matrix controller, of which the backlight controller is a part.
All manufacturers react painfully to “shock” defects. Having a dent in a wheel rim can easily void your suspension warranty.
A broken hinge is not necessarily a consequence of the impact, in the absence of obvious marks on the case. There was a service mailing from Lenovo about defective plastic parts - the fragile material of the case led to breaking out of the hinge nuts of the hinges.