LCD display works, but brightness/backlight is dim
I just purchased a used MacBook Pro (13-inch, mid 2012). NON-retina display. Everything works fine, but the LCD screen seems a bit dimmer than it should. When I turn the screen up to full brightness, it doesn't seem very bright. When brightness settings are turned down low, the screen is nearly black. Everything seems to display okay, and the colors are fine. I calibrate the monitor with a Spyder 4 Elite, and the color rendering is acceptable.
Wondering if replacing the backlight would solve the problem? If so, is it possible to replace the backlight only, or would I replace the whole LCD? If it's the LCD, would I need to replace the entire LCD assembly or just the LCD panel. (I think these LCD panels have integrated backlights, but I'm wondering how to tell if the problem is in the backlight or somewhere else in the computer/display assembly.)
Other relevant tech specs:
Mac OS Sierra 10.12.6
Processor 2.5 GHz Intel Core i5
Graphics Intel HD Graphics 4000 1536 MB
Is this a good question?