Good day all. I wanted to share my solution to a problem that could happen to many of us. I have a Cannon safe with an electronic lock. According to the manual, when the battery is getting low, a series of beeps will occur as the combination is entered. These "beeps" are at a very high frequency: apparently in my hearing loss range. The day came when my safe would not unlock. Instructions say When changing the battery (9v) first unlock the safe (duh). I was able to remove the battery and its connecting wires from the battery compartment. The top cover of the battery connector is removable, exposing the terminals. I electrical taped a fresh battery to the worn one, aligning polarity. Eighteen gauge solid copper wire (approximately 3 inches long each) was soldered to two 1 1/4 inch alligator clips. Each clip was connected to the terminal on the fresh battery with the bare end of its connecting wire inserted into and making contact with the terminal of the worn battery (+ to +, - to -). It would not unlock immediately, so I waited 24 hours (for a capacitor to charge?). After that time passed, the combination was entered, the unlock wheel turned, and the door opened. HUGE sigh of relief. During the two weeks between the times the door would not unlock and when it finally did, I literally lost sleep over this. Needless to say, spare batteries will be stored in the safe with notes on when the one in service was last changed. This is being shared in an effort to save others the grief I experienced.