For U3 purchased from other than Bitmaintech.com, please PM us with your original proof of purchase (showing the payment date, shipping tracking from the seller, and a payment method) and description of what is wrong with it.

Original Buyer has 90-days of warranty from the date of purchase.

Resold units don't reset the warranty date based on your purchase date if you purchased it from other than Bitmaintech.com

To be considered for repair/exchange, PLEASE provide BitmainWarranty with your full purchase info and after-sale issue correspondence with the seller who decline to assist with you. (If there was no response from the sellers, please provide us the proof you attempted to initiate the contact but no avail.)

If you were given authorization to return to Denver, Colorado address, please include the PM authorizing you to return with the original purchase record with the miner.  

thank you!