NomadGroup..

It is complicated repairs the hash board of bitmain .. I just received 15 machines r4 .. and a hash board was damaged .. So it is contacting them .. for the warranty. The new s9 they do not only want the hash board, but the complete unit ..

Please contact bitmain, so they can guarantee you for your bad cards ... they take about 30 days to return your repaired cards ..

I can help you .. in the irc .. I spend with the boys ... Let me know

regards

The repair is not so much money .. and includes the return shipping