Hi
I would have gone with a board issue.
As pointed out above I have some for sale so let me know if you need one.
As for you battery choices :
9V , don't use them in your halo / reloader they just don't work well and they cost too much, save them for your marker.
AA's. Don't ask why but Reloaders are picky over the amount, 4 or 6. It seems to depend on the release of the board that you have. I have used plenty of different Reloaders over the years and the 6 battery harness has always been the best.
I have had a few that are capable of using 4 and they worked fine like that too.
So use the 6 battery option and get some good batteries too, no Sainsburys own rubbish here
Hope that helps mate.
Dave T is always a good source of knowledge when it comes to loaders too mate.
Ed