Batboard

Hi guys, have a problem with a gang charger.
It started out as a V3.3 impres charger, when a battery was dropped in it flashed yellow, indicating standby.
A friend upgraded it to V3.4 and I thought all was good, when a battery is dropped in, it goes red, then after about ten minutes it flashes a quick red, and will keep flashing until the battery is removed.
I tried a force charge but still no go, what gives?

Thanks

Any battery, or one particular battery?

All batteries, new and used.

I am going to see if it has something to do with loading/input power to the charger by disconnecting all but one and try that.