Toshiba e740 Pocket PC PDA problem

Hello,
hope someone can help me with this problem...
When the standby button is pressed or after auto shut-off (during battery operation) the unit switches back on after about a second, this does not happen when the unit is being powered from the cradle or other external sources. The consequence of this is that the unit cannot be used away from a power source for extended periods, as with all the e740 series if the battery power is allowed to diminish the data held in the device is lost. I don't know if this problem is being caused by the PDA or the battery and I don't have access to spares to carry out tests.
Kind regards