Boss BR864 wont run off of batteries

[VS1]

I have a Boss BR864 portable recording unit which is fantastic when recording on the move. One of the benefits being that it can be run off 6 AA batteries or an adaptor. My problem is that my unit has suddenly stopped running off of the batteries. It still works fine from the adaptor so its not the end of the world but it is frustrating. This literally happened overnight and there is no sign of leakage etc. I have also tried various different batteries with nothing. All the batteries are connecting properly to the plates/springs as well. Anyone know what this can be and how to sort it?

[grooverthebarbarian]

If its still under warranty, I'd contact support. If not, have you cleaned the contacts? It's the only obvious thing you can get at without ripping it to pieces. Get some emery paper and give the flat contacts a scrub over, but if they look clean in the first place, there's probably no point