Switch in off position, install battery, camera powers up.
Inherited this D70. Don't know any history on it. Camera will only power down by taking the battery out. I can turn the switch on or off and it makes no difference. Seems everything else is is opperational.
There have been a few reports about the same issue. It can be something as simple as a contact problem with the ON/OFF switch to as complicated as a shortened SMD resistor. It is also possible that your camera may my have a write function error. This could lock up the when the buffer got full and wont clear after that. When you pull the battery and then reinsert it, you manually clear the buffer. So as you can see, there are a variety of possibilities. Here is a decent site explaining a bit about the SMD part. the other thing I would try and do,is a firmware update, for that check on here. The complete Service manual including parts list and schematic is available right here. Hope this will get you going in the right direction. Good Luck
A follow up to my problem.
Obtained an exploded view of the camera.
Found the location of the switch and contacts so i'd know where to look and what it looked like.
Followed the dismantle and assembly instructions, on this site, to get to the switch contacts.
Saw nothing amiss and mechanically seemed to actuate properly.
Took a common pencil eraser to the flexable circuit board at the on/off switch.
Polished the contacts to remove any foreign material or oxidation that might be causing a constant closed circuit.
Reassembled and BOOM!, She works like new!
Thanks for a great site and your willingness to help a stranger!!!!!