Might be worth getting at least one that works, and then try my luck with some of these "as is" ones.

If they offer one for double the price that you listed, and it does work, I’d choose that personally. Fixing it after it breaks usually means one thing broke, but if you get one in an unknown state, who knows how much is wrong with it. Just my 2 sats

Edit: buying these for spare parts seems like a reasonable choice given you want to work on them

bitcoin_Mining

"As It Is" Antminer S9 From D-Central

If they offer one for double the price that you listed, and it does work, I’d choose that personally. Fixing it after it breaks usually means one thing broke, but if you get one in an unknown state, who knows how much is wrong with it. Just my 2 sats 

Edit: buying these for spare parts seems like a reasonable choice given you want to work on them