s17+ all three hashboards failed at once

Hey everyone I just got my hands on a couple of used s17+ miners, they looked good on the outside. When I picked them up, I checked them out for about half an hour, and everything seemed alright hashrate was on point, kernel logs were normal, and temps and fans were doing fine. But after driving 200km to their new spot, one of the miners just stopped hashing after about 2 hours. No matter what I’ve tried, it won’t come back. After a restart, I saw logs saying 0 asics detected on all three boards. I went ahead and reinstalled the firmware from June 2020, but it didn't help. Reached out to Bitmain support, got a link to some factory firmware, still no luck. Updated to the latest firmware too, but nothing changed. Now I’m running Braiins off an SD card, but still no improvement. The other s17+ right next to it is running like a champ, so I doubt it’s an environmental issue box is around 58, chips are at 72, and fans are all running at 3k. I mean, I could understand if just one board failed, but all three at once? That’s a bit weird. I do have the chance to swap the hashboards between the two units to check if it's a controller or PSU problem, but I’m kinda new to this hardware. The process doesn’t look too complicated, but I’m hesitant to mess with the one that’s working. I’ve also tried disabling different combinations of hashboards while running Braiins, but that didn’t change anything either. If anyone has any ideas on what might be causing this kind of total failure or any practical steps I could take to troubleshoot further, I’d really appreciate it. Happy to share current logs if they’d help.

Yes if one hashboard is failing it could affect the other 2 hashboards if you want a better analysis for this unit I suggest you post the whole kernel logs here. I guess that hashboard have a connection issue replug all cable PSU and ribbon cable from the control board and hashboard should fix this issue. You can also try running them one by one if you suspected the PSU just disconnect the two hashboards and run only one hashboard to test which one is running fine. Also, check the PSU connector and test them one by one and then update here the result including logs.

Im so glad I sold all my S17+ last year. They are all garbage quality, but thats not what you want to hear... I would carefully try each hashboard one by one in the working miner to see if any hash.  If the ALL hash it is certainly a power supply/controller issue. Buy extra PSUs/controllers for these machines.... If 2/3 hash, the bad board is killing the good ones and not allowing the unit to work. Could also be a controller failure. You could try the good controller with the good hashboards (after testing) and see if that works. Swapping controllers sometimes works.

Thank you BitMaxz and JonnyRocket for the replies. As suggested, I removed (and air cleaned) all three boards and tried them one by one.  All three work.  Plug them all back in an 2 out of 3 work.  Swapped the ordering in the unit, to find the same board fails.  Swapped that one board into the other unit that was working fine, and not surprised to find that now hashes on 2 of 3 (incidentally I put the one I pulled from the working unit into the 'bad' unit and that runs 3 of 3).  So it would appear that I do indeed have one bad board, and having cleaned and fiddled with all the connectors whilst testing, I am now in a position where it does not prevent the other 2 boards from working. I found it odd that the 'bad' board did work when it was the only board in use, however I only let it run for 5 or 10 mins before continuing testing with the other boards.  I want to run that test again for a longer period, then I will get some logs on here once Im happy I have done everything possible from a physical point of view. T