Did I install the t-con board wrong? I was having flickering on my sharp aquos and replaced the t-con board. Now I get no picture.

After I thought the new t-con board (verified exact same part, ordered on tv parts today) was defective because I got no picture after installing it, I decided to swap back to the original t-con board. when I did that I still had no picture. Which made me think I installed it wrong. I undid the cables, reinstalled the ribbon and the menu appeared on the TV when turned back on. So that made me think something wasn't set right w/ the ribbons when I installed the new t-con board. So I swapped back to the new one, and after trying to make sure I set the ribbons correctly, I still have no picture. So then I went back to the old t-con board (because as I just verified, it was working after I re-installed it the 2nd time) and now I STILL have no picture. I swapped back and forth a couple more times and I can't get any picture to show up. So that makes me wonder did I possibly fry something (I was very careful, kept myself grounded, didn't get rough w/ the ribbons, etc) or is it something like the ribbons are just extremely sensitive and maybe they're still not set right (they're very hard to reach)? Any thoughts on how I could test the t-con boards to check if they're good and I didn't blow something? I saw a video that it's possible w/ a multimeter but I'm not sure where the fuses are on the board or which area to test. Thanks in advance.