When testin a power supply or led board on tv do i test dc or ac with multimeter?

Do you have the panel out? You said all the backlights work, were you able to see them all light with your tester? If so I'd lean towards main board issues. On most larger Funai brand sets one shorted lamp will shut down the inverter from over current.

Chances are it's bad backlights if you can see the image with a flashlight

There is three possibilities:
1. Defective back lights LED strip.
2. Defective LED driver section integrated in the main power supply.
3. the main board.

How to check it:
1. You need a LED back lights tester to check the strips, or open the panel, use a 3.7 V DC power supply to test each LED diode separately.
2. Use a multi meter to test the out put DC voltage from the connector to the LED strip between the + & - for each section, (like 1+/1-, 2+/2- etc.) it should read 140 - 220 V DC. (need power up the TV).
3. Un-plug the cable between the main board & the power supply, power up the TV, if you get the back lights light up, the main board is bad.

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://electronicshelponline.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.

Hi,
This model develops bad solder joints on the connector between the power supply and the led driver board and loses backlighting. It's hard to believe, but the whole connection goes bad. All those pins supply only 24v and gnd. Resolder all of the pins on the power supply half of the connector and the tv will work.
It's the connector between that large yellow board (p/s) and the center green board (led driver).

invariably the LCD backlight inverter board or the LED driver board are the usual suspects. or the T.Con board

see the video below and follow the logic of elimination process
LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...

If you can see an image on screen via flashlight test then the backlighting is not working. And the inverter board is the unit that powers those lights ..... So....................

SONIQ LCD TV REPAIR Blank flickering screen Energy ...

? 1:32
https://www.youtube.com/watch?v=FUqdi7lwmcE
May 29, 2013 - Uploaded by WastedOne2
Fix ya Soniq Tv once loaded up hit menu button then channel + then ... SONIQ LCD TV REPAIR Blank flickering screen Energy Saving Mode Issue ... Easiest TV repair - How to Fix Power [TV turns off, freezes, or won't turn on] ... Common easy LCD TV fix: bad picture screen rainbow colors - Duration: 4:04.

No Image & Blank Black Screen Flashlight Test - YouTube

? 5:56
https://www.youtube.com/watch?v=xUzCLgoSPGM
Sep 15, 2014 - Uploaded by ShopJimmy.com
LCD & LED TV Repair - No Image & Blank Black ScreenFlashlight Test - How to Fix LCD & LED TVs ... Most LED TVs will have a t-con board, a power supply board, a main board and an LED ..... SONIQ Australia 1,718 views.

Soniq PT42SH plasma TV power on. No back light and no ...

SEIKI Tv SC501TS has audio but no video, repair - YouTube

? 1:38
https://www.youtube.com/watch?v=cWpF4q_rBaw
Oct 19, 2014 - Uploaded by EurekaRecycler
SEIKI Tv SC501TS has audio but no video, repair ... LCD & LED TV Repair - No Image & Blank Black Screen Flashlight Test - How to Fix LCD ...

LED TV Repair Main Board Overview Blank Screen-TV Has ...

? 2:57
https://www.youtube.com/watch?v=-TU2KSuect4
Mar 4, 2014 - Uploaded by ShopJimmy.com
Learn why your screen is blank and you have audio - No image LED TV Repair Review Main Board Problems ...

LCD & LED TV Repair - No Image & Blank Black Screen ...

bad inverter, power supply
LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...
about 4 min in he will explain it