As far as S5+ I only have had one but had good luck with it -
https://bitcointalk.org/index.php?topic=1157426.0So I don't think your problem is related to S5+ in my eyes. Since it's new you need to make sure to contact bitmain to get warranty work. I'm assuming did you buy from bitmain or did you get elsewhere?
I did have a S3 with temp problems they told me as long as it had 1 working it was fine. So I ran it with one and it worked fine. I'm betting they tell you it's fine as long as one is getting a temp. But they might have changed policy as that was in S3 day's.
... as I mentioned the S7 units shipping with that same board I also have an original S5+ unit with that same board and while I had some minor complaints outside of shipping times with the batch 1 S7 units, both my S7s and the S5+ are all using that same board.
Did you have any issues with any of your S7 units notlist3d or did you pickup any of the S7s? I don't recall reading where you did or not.
Either way, the control boards being good on the S5+ for us doesn't mean you don't have an issue by far as others have, but as notlist3d stated you should get your warranty handled ASAP. The sooner you do, the sooner you are back mining witht he least amount of difficulty because that shit isn't slowing down until the spring. We are going to see bombastic incredible difficulty rise. So what you have mining now is what is important.
If I was in your shoes at the moment I would do one of two things.
1. If you have a buddy with multiple S7s ask him to sell you an S7 control board and double two of his up. IT has been shown too many times this works without issues, and he could get you one fast (if so inclined) while you process the warranty on yours, and that would allow you to prove it is 100% that board.
2. If no buddy on the scene then buy one from bitmain. It isn't like you couldn't sell it, and probably for a profit. But you would be running regardless.
Before doing anything though, I would speak with bitmain support, get that ticket going and perform the steps they want so you are setup for warranty.
The absolute most important thing at this point is do not waste time with decisions. Lay out all of your options, make a choice, and move on it quickly.
After 3 more months of the difficulty increases we are about to have it isn't going to be pretty and the people who make ROI will be selling units AND maintaining up-time. Spare parts can make a huge difference.
DO NOT let bitmain or anything keep your unit down for a month. If you are looking at 4 weeks down, sell it now and order another.
I'll bet you can sell it for at least what you paid even with issues, unless we are talking VAT on top or something similar, but you could get 1600 easy on ebay even with what you have described. IF you have to go to ebay, I prefer the forum here for sales.
Best of luck man!
