So is it the last miner on the chain?
If so I would suspect cables.
But if it is one of the miners in the middle of the chain I would need to think about it.
What is the power brick 5 volts 2.5 amps
Or 5.1 volts 2.5 amps.
The official rasp pi brick used in the cana kit is 5.1 volts and 2.5 amps