I have 2 units that are sometimes working, sometimes not. S17 Pro and S17+. One has dead hashboard (exactly one loose heatsink) while all 5 other hashboards sometimes work. Where are you from and would you try to repair them or want to buy 'em out?
I'm in the northeast USA.
I'd consider buying them, but if they are partially working it may be better for you to limp along with them while profitability is as high as it is now. Guess that depends on how often the 5 sometimes working hashboards go down.