Ah... okay, I think Lenovo tech support is a bit confused.
LCD screens have one of two types of backlight; CCFL and LED. CCFL backlight uses florescent lights while LED backlight uses LEDs. To the best of my knowledge, only LCD screen with CCFL require an inverter which converts AC to DC power. LEDs uses DC power so there is no need for an inverter.
The Lenovo Y510 has a LCD screen with CCFL backlight while the newer Y50-70 has a screen with LED backlight. I think the only way to fix your problem is to replace the screen. Here is a link to such a screen.
https

/www.amazon.com/Lenovo-Replacement-Full-HD-Substitute-B156HTN03-6/dp/B013KRC3PY