Hi Mikey, yeah I’ve already tried that. No matter which boards I use the miner will only run with 2 boards in. Any 2 of the 7 boards I have it will run normally. But as soon as I add a 3rd board it does the reboot cycle. Ive spoke to Oliver at whatsminer and he’s told me the miner has been tampered with, the label on the case isn’t original. Not sure exactly what’s been tampered with but I’ve tried 3 different control boards, numerous variations of hashboards out of the 7 and I’ve just got a new PSU that I need to try. I’ve also contacted coinminingcentral again after finding out the label isn’t original, their reply was that it’s a USED unit and that it was all tested before shipping to me. I mean I understand there’s no guarantee with a used unit but one with unoriginal parts?? Would never buy a used unit off them again. Their support was ok trying to help me, trying different test to figure it out but they’ve since cut me off basically, they’re no longer replying to me.
I wouldn't even argue that Oliver observation isn't correct, I would trust his judgment without a second thought, however, fake labels don't mean much, not in your case, fake labels aren't new, scammers have been using them since the S9 era, they would change an S9 to S9i or an S9j because the S9 was cheaper, but the end result was that you get a slightly less powerful gear, there is no other gain from the scammer.
The other reason would be if they sanded the miner's body or made a new one to make the already-exhausted gear look like it was just used for a few weeks, but doesn't matter why they did it, it doesn't mean the whole miner is fake, it's not like they can make an M21s hashboard that does hash on it's own but not with another hashboard, Oliver probably knows all this, but he spared you the details and it's like he wanted to tell you that the fact that the gear has fake labels, the possibility of the things that could be wrong with it are endless.
However, now that you revealed that last piece of info, I think your best bet would be the PSU or the busbar/screws, make sure you tighten the busbar and then if that fail, the second test you would do would be running the miner on low power mode, if it's a power related issue running on low power would probably fix it and that would confirm that you have a faulty PSU.
Anyway, if you download whatsminer tool it would reveal a lot of helpful info, like the amp, voltage and wattage of the PSU, even the PSU temp for that matter (although not sure if the M21 has that function I know all M30s do), anyway, if you want to download the tool and something like Anydesk, we may arrange so I can access your PC to check the miner for you, or you may just run the tool yourself and send me screenshots of all the columns.
