Will 2nd Gen Nexus 7 power on w/o back case?

Let me explain: I have repaired many First Generation Nexus 7 tablets, and they will power on without the back casing intact. I do this just to make sure everything is in order and working properly before I put it on, saving me the trouble of prying it off again. However, I just replaced the screen on my personal tablet which is the second generation (2013) model, and I cannot get it to power on with the back casing off. I noticed that there are little "connectors" on the back plate that would make contact with the frame when put together. Is this what keeps it from powering on when the back case is off? For those who are wondering why I don't just put the back case on and see if it works, the reason is that the Chinese based eBay seller who sold me the frame/ screen combo did not include the volume/power flex cable, so all I had was an old 2012 model flex cable that will not fit inside the case properly (but it does fit in the ribbon slot). I am sorry if this doesn't make any sense. It is really hard to explain.