backlight problem ... inverter? panel? wire o logic board?

hello guys this is my first question here so be patient with me (and my bad english)

i have a backlight problem with an imac model no: A1224 and EMC: 2266,i have followed your guide to disassemle it and now i m confused on what is broken on my imac; those are the test that i have do:

- if i power on my imac and use a led torch to illuminate the display i can see everything and everything works great.

- if i disconnect the ccfl lamp cable from inverter to put 4 fully working ccfl (refurbished by a broken lcd monitor) and power on my imac the ccfl lamp dont power on

- if i measure with a multimeter on 4 pin connector on the inverter board i can see on the upper 2 pin 12v and nothing on the other 2 pins

- if i measure with a multimeter set in continuity mode the cable that connect: (first 2 pins) power supply to inverter board and (other 2 pins) logic board to inverter board everything "beeps" so the wire i suppose that is good.

my inverter board is a Apple part number 612-0051 someone can tell me what is the rigth pinout/voltage on this fully working board ??? i don't want to buy a new inverter if i'm not sure that it is the problem.

Any help, other test or suggestion are really appreciated regards