You'll probably get a reply from Davinci on here as they are quite prevelant on this thread.
I would honestly suggest opening an rma with them as tinkering around with things like this doesn't seem to make sense. I understand your frustration I look at things this way - take the value of your hourly pay rate and times that by 1.5 now think of all the time you are going to spend frustrated and trying to fix this vs opening up an rma and getting it sorted properly - straight from the source.
I don't think the problem you have would take too much to fix but I don't currently own an Iq and have never physically held one.
I will be purchasing one later on this week. So I'll probably be a little more knowledgeable soon. I take it you've seen puffitup's tear down page
https://blog.puffitup.com/2017/08/da-vinci-iq-teardown/
I really wouldn't recommend doing this though unless you're 100% confident but it might give you a bit of insight or at least you could compare your parts to the ones on there.
*After thought have you tried removing the flavour chamber completely and trying to power the unit on to see if that helps. Is this even possible? Can you use the IQ normally (without your issue) with the flavour chamber removed?
My serious suggestion would be to contact davinci. They know what they're doing. They will look after you.
I've seen the tear down and I'm not confident enough to attempt something like that.
Also I live outside of the U.S. so an RMA would take quite a bit of time and money to be completed since I'd have to ship it out and then back in again.
The battery door latch upon closer inspection got warped or damaged during the fall, because the unit can and will turn on if I apply enough pressure to it (Battery door).
Also the spring/battery terminal within the unit could have also been affected, but I'm not trying to tinker with that either until I've read/heard info and solutions.
The Davinci rep is pretty deep in here and he's offered to help me with my RMA process before (For my first IQ), but I'm saving all of that for when I'm completely out of options.
As for your question about starting the unit without the flavor chamber, you can. Once the unit is being powered by the battery, it works. My problem is that the battery is not making contact properly on either the top (Battery door) or bottom (Battery terminal). The chamber isn't the problem in this case.
Also, as a semi seasoned user to an IQ newbie I'll give you a few tips that I wish I had known when I first started.
-LEAVE THE PEARL ALONE. The more you fiddle with it, the greater your chances are of damaging the post.
- There is a chamber to clean UNDERNEATH the flavor chamber tube that also affects taste/performance. Cleaning the chamber and oven isn't enough. Don't wait until you get harsh vapor/flavour to do so.
- tough draw resistance? Don't pack the bowl TOO heavy/tight. Also the 10mm mouth piece is easier to draw from than the little raised lip mouth piece for obvious reasons.
- Be very mindful of the nectar collector or any other water attachment that sits directly above the mouth piece. Water falling directly into your unit while it's on and hot WILL mess it up, even if once.
(This could be inexperience on my part with the nectar collector but still, be mindful)
Enjoy when you get it, man. It takes some tinkering, but once you get comfortable, you'll be well on your way with this beauty.