very unfortunate situation. I have a brick that I paid $6,000 to acquire. still waiting on that missing backplane.
wary of sending anything back to AMT since they don't seem to be receiving anything nor is there even a chance of getting anything back.
Given the slim chance of help for ya, for now guess it's up to us...
As ISAWHIM said, the backplane can be repaired. After repairing it what needs to be done is find what card caused the overload.
Trouble shooting basics:
With backplane repaired, and inspected for any shorts along where the trace burned:
Remove ALL of the ASIC cards and plug in only the floppy power connector. No GPIO to the backplane yet.
Briefly power up. Any smoke?
If not, power down and GPIO cable time, along that line; Is the GPIO card plugged in right? If the board sockets are not keyed if lucky there is P1 label on the sockets to identify which end of the socket gets the red wire on the ribbon cable. If no label, then standard practice is to have the cable leading straight out from or into the edge of board, not folded over the connector. No guarantee on that.plug the GPIO cable into the backplane and either the RasPi _OR_ the mainboard that has the 24pin PSU connector on it. Not sure how AMT did it... Opieum, since I don't have a miner just guessing so comment on that?
Dragons look like they use GPIO from a real RasPi to the mainboard and then a cable from main to the backplane.
Briefly power up. Any smoke?
Turn on again and see if you can log into the RasPi.
If you can that only leaves the ASIC cards which will need close inspection around where the backplane plugs in.
The 5v most likely feeds the SPI interface and a data signal level translator for ASICs. Hopefully should not be too hard to see where that 5v rail is being shorted...