Before returning the faulty control board only, kindly be aware that you need to pay the repair fee which is approximately the same as the current retail price of the control board regardless of your miner's warranty status.
In the event that your miner is within warranty and you would like to have the control board replaced by our repair sites without any charges, please return the whole miner as detailed here:https://service.bitmain.com/support/guide
As for your reference, you can always choose to purchase a new one at our official website: https://shop.bitmain.com/product/parts
We really appreciate your attention on this matter and we will do our best to serve you wholeheartedly.
Bitmain After-sales Support Team