Antminer D3's can't compute SHA-256, it's designed for X11 algo of coins like DASH and copy-cats/forks 
Forget the chance to mine a block, can it even mine Bitcoin at all?...
Forget the chance to mine a block, can it even mine Bitcoin at all?...
You are right I made a mistake it was one Antminer S7 and two S3, not D3. I got them for free from my friend Crypto Mania and started to play with it.
They are still mining because I handed them over to another crypto enthusiast who wanted to start his mining journey
.As for now, they are running and my friend still counts to find solo BTC block, but I rather doubt that this is possible.