Yeah, I use some "generic" pre-built photos simply because 99% of all TV's have the same layout on the boards, just a little different from model to model.
Samsung TVs don't use fail codes, so the double blink just means the main board is attempting to turn on and it's not getting any of it's startup signals back to it.
In other words, we may be looking at the Ymain....the Xmain....or the power board isn't firing up.
The meter helps us because we can test the power supply to see if it's providing the voltages needed to power up the X and Ymain boards.
I suspect we'll find the Ymain bad, and the power supply is next on that list. Xmains rarely fail, but there is an exception and it's Related to how the Wiriing between the Power supply and X / Y mains are laid out.
Here, let me show you the two wire layouts you find on all Samsungs --
The lowest picture called the Daisy Chained wiring....I've seen the Xmain short on those. The upper picture with they WYE wiring....Ymain is the more common failure on those.
We get to know our TV sets pretty well, so the wiring layout does have a lot to say about where to start troubleshooting.