Not the battery - the A1000 has no battery.
Not likely DF0: either. You would see the kickstart prompt.
The most common thing of all may just be parts working loose. Check out the memory expansion that you have in the front of the unit under the removable middle plastic cover next to the floppy drive. If this is loose it could be your problem (maybe remove it completely to rule it out)
If that's not the problem, some of the socketed chips may have worked a little loose and need to be pressed back into place. This is a bit of a chore because you have to take off the cover and RF shield.
