Have a look at the link below - Seems like this other member may have a similar issue with their A70 - Looks like moisture might have been a contributing factor - If so - Put your device in a baggie half filled with uncooked rice.
If you still have the problem, then I suggest you to try wiping out the cache data. You can do it by first shutting down your A70 and hold both power key and volume up key until you enter the recovery mode. Navigate to "wipe cache partition" using the volume keys and select it by using the power key. Please let us know if it is fixed.
