The problem is likely your controller.

To get your 6 boards to work on one controller, copy the 18 pin data cable connection layout from the forum link posted before.

If you plug them into the wrong plug the controller won't recognise the hashing board.

I have the same problem with one of my controllers.

One of my boards in one miner won't show up unless I don't power on my controller board for about 10 minutes after the hashing boards. But they still drop out eventually. Sometimes 2 days, but other times, like right now, within minutes of running.