42lg7000 wont switch off

[mali67]

heres a new one on me i have in an lg427000, it wont switch off by the soft touch power.
when on and you press the power to turn off , the red led will glow on and off then the backlight flashes on and after a few more red led flashes it will come back on....

sorry im not very good at explaining thing but basicly the tv wont turn off.
any help would be apreciated

[mali67]

this is what i have found, after checking all voltages , they are all fine.
however if i turn the backlight down to about 85 the tv turns off.
i noticed when i unplugged the antenna or it was on av without signal it would shut down, so i turned the backlight down on each input and its working.
this isnt a fix, im thinking a faulty inverter, but then it could be the mainboard which supplies the signal to dim, or the psu ?
any ideas would be great, cheers