or where to send old ones for repair in USA?
1.
Bitmain US repair site - Usually takes longer than below option
Name: Tomrepair-Bitmain
Address: 5640 Grace Place, Commerce, CA 90022, USA
Tel: (+1) 626 362 7240
2.
MyRig - Separate company but faster repairs
3700 Quebec Street, Unit 100-239 Denver, Colorado 80207
support@myrig.com