The easiest way to test the LCD inverter is to test it with a known good backlight.  In this case I tested the inverter on a HP dv6000 with a known good backlight from an older Dell Latitude C600.  The test backlight did light up so I know the inverter is working.  If the backlight does not light up then the inverter is most likely bad.   In case you do have a bad inverter check out my other post for fixing a bad inverter.

dv6000-lcd-9c

Test the LCD inverter with a known good backlight. I used
one from an older model Dell.

Backlight comes on meaning the inverter is in working
order.