Lenovo SL500 Laptop motherboard is not giving enough voltage to turn the screen on

Hi, It is a follow up to my earlier question.

Now I know the screen is good and inverter is good.  Is there any way to fix this motherboard so it gives enough power to the inverter to turn on the screen. - thanks
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The only way I know to do that , is to trace where the plug on the mother board is with power to the mother bard on.

Set your multi meter to DC volts and find a ground on the board and place your black prob.

Now use your red probe to  trace back from the the plug until you find the 12 v  . It may be an surface mounted , cap, resistor, ect and it my Be an IC on the board that has failed. If you find the failed component you can order a replacement.

You can all so use a small jumper wire from a known 12v source on the board and run it to the pin that powers the inverter.

I have soldered in a jumper wire like this to test with and it works , but I have not use it as along term solution , as the power rail that powers the pin has a number of , caps, resistors, etc that smooth out and control the voltage.

You can try at your own risk. You have nothing to loose , as the board will most likely need to be replaced.

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Press2EscSystems IntegratorCommented:
The basic electrical components dealing with a laptop LCD is the LCD screen itself, a video controller, backlight inverter, power supply and cabling.

What makes the LCD viewable is the inverter and the voltage is stepped up to several hundred to a couple thousand of volts. The LCD "inverter" converts DC to AC volts. You can only verify the input side of the inverter is getting the req'd 5-12v DC, the output side - which is what you wnat to check- can not be tested via a generic digital volt meter (DVM).

So by definition, if your LCD pic is dim, your inverter is not working.  If you insist the inverter is good, check the cables & connection.

You could supply power to the inverter from an external power source if you have one for testing. If you have a variable DC power supply it will be good. Then you could v vary the voltage input and test.
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