Any ideas on how to properly test voltage on the LCD inverter input and output?

My Satellite 5105-S701 fails to light the backlight.  I can see the image when using a flashlight and the image on an external monitor is fine.  I tested the output from the inverter board and am getting zero volts.  The input has many fine wires and without a pinout I have no idea how to test for voltage going into the inverter.  I took it to a laptop repair place and told them I thought it had a bad inverter and would they please diagnose it for me.  I guess I was too specific because when I picked it up they simply told me the inverter was OK and handed it back to me with the backlight still not working and no idea why it’s not working.
Any ideas on how to properly test the inverter input and output?  I would try a known good inverter but I don’t have one.  Any other suggestions as to why the backlight won’t light? Or any other tests I can run?  I’ve found all the software backlight controls and they’re all cranked up.  Thanks for any help!

That’s a question I keep asking myself over and over. How can I test an FL inverter board using just a multimeter? Unfortunately, I do not have any straight answer at this time. I believe that you can measure the voltage on the input if you connect the positive probe to the pin 1 on the FL inverter and the negative probe to the laptop chassis. The multimeter should be set to test DC voltage. I think that the voltage on the input could be somewhere between 9-30VDC, just in case set the multimeter to a higher voltage. The pin 1 on the FL inverter board should be marked; I’ve seen it marked before. You should get some voltage on the inverter input. If you get zero volts on the input, then it’s possible that cable is bad or the connection on the system board is bad. Now about the output voltage. I believe that you can get an accurate readings on the FL inverter board output only if it’s loaded properly, in other words if the backlight bulb is connected and it’s in a good working condition. It could be a very high AC voltage. I would set the multimeter to at least 1000VAC. Be careful, it’s a very high voltage and if you do something wrong and short a circuit, you can permanently damage the laptop. Sorry, but I cannot provide more specific information. If you find any info on how to test a failed backlight with a multimeter, please let me know.

Usually, when I have a problem with the backlight, I unplug the screen and connect my test backlight bulb. If it lights up fine, then the backlight in the LCD screen is defective. If it doesn’t light either, then most likely it’s the FL inverter board fault. Video cables do not fail very often.