I have a Sharp model LC-58Q7370U turns on with sound no picture what board do i check and would replacing all of them in the unit solve the problem or could it be the backlight strips themselves

Possibly no 'hand shake' signal from the main board. Is the stand by power supply voltage the correct voltage and did you check the output voltages of the power board.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electro-medical.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

You can either remove the power supply and check and replace caps and most likely the transformer (pop sound). Or a replacement can be found on eBay, amazon, etc... One model TV can have numerous diff power supply models from revisions and improvements. If you replace the board make sure you look match serial numbers on board to the new board. The back of the TV will come off very easy. Lay TV face down on a flat surface(making sure nothing is touching the LCD) remove screws. (Make sure cable coax slides free, some have a retainer but to remove) once the back is off the layout should be so simple, you should have no problem identifying parts.

Final Up date, The TV is fixed, with my problem it was found that the units Mainboard was defective. If you go to replace your Mainboard MAKE SURE THAT YOU PURCHASE THE CORRECT BOARD AND VERSION NUMBER OR IT WILL NOT WORK...... for example KE833 XE833WJ and the most important part, look for the version on the White lable markings, mine was FM11S it will be some FM number that will be used on your Set. Hope this helps you solve your problem.

try replaced main board
Manufacturer Sharp Part Number DUNTKE373FM03S Description P.W.B.UNIT

Ur Tuner board have problems,just not dead yet.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish Tuner board for the replacement.Should solved this problems.

This problem very common in sharp tv.The POWER,OPC flashes.First turn on have power LED indicator light stable at all? Tries the power again couple times will have backlight come back on,than it will work.Not at all more than 5-6 times than ur main turner signal board is the problem,must replaced.

Part called main unit failed and require replacement. part number duntke352fm02.