I have a query that I would like to check before I do anything. On my stats list of the A2 it has the ID as 0 to 4. Am I correct in assuming it should go up to 5 and one of the boards is either disconnected somehow or dead? Or is there something else I have missed.
You're talking about under the realtime stats, correct? If so, all of the Terminators I have have 6 blades, 0 through 5. Now, this isn't to say that InnoSilicon didn't make some 5 blade versions, there seems to be about a million variations of the hardware from them. I would say this first - assuming you're running my firmware, and running at 1200MHz, on that realtime stats page, what's the SUMMARY MHS av/5s? Those are what you're actually hashing at, so if you have a 110, and that number is in the 90's, then you have a blade that's down.
Next, look in through the front, if one of the blades is having problems connecting, in most cases the green LED's on the front will flash. When you reboot the machine, they flash on all the blades, and as they each are initialized they stop flashing. So if you see one of the blades flashing, then you know which blade is giving you grief.
Then once you know the culprit, I would open the case and make sure all the cables are seated tightly on that blade, both on the blade and back to the controller. The connectors are super finicky on the A2's, so making sure they're in nice and tight and getting good connections (obviously do all this when it's turned off).
Finally, if that doesn't resolve it, then try swapping the data cable with one of the ones next to it, just swap the part that connects to them - this way if the blade STILL has the issue, you know it's the blade and not something else.
You can buy replacement blades from InnoSilicon - it's a pretty painless process and they aren't overly expensive.
Hope that helps and let me know what you discover.