Help! Worked but now it doesn't work

Here is my speel. I have been at this project for a while now and I will explain my situation. I skipped ahead the steps for building the case for my portable nes (using Ben Heck's guide) because I wanted to see if it works. If it does, I will invest more money into it. If not, scrap it. So Yesterday I connected power to my finished right board which at the time was not connected to the left board. Without the leds, the screen ran fine, not showing a nes game but I could tell it was on. When there was power, the screen would go from black, to a sort of "light black". I KNEW IT WAS WORKING! But then, today I tried it and nothing. I checked using a volt meter that power was going through all the components. Please list all of your possibilities. Also (this may have to do with it) on page 153, one part of the diagram is confusing. The letter "j" is not properly labelled. I do not know where to attach the right board to. Please help me as I am in distress!

Thanks to all!


P.S Is their something I could have missed?