How do I fix my sharp UP-700 the key hole felt into the register

Consult a locksmith, Claudia!

Hello.

My name is Alain and I am a cash register technician.

I assume that when you talking about the lock that fell inside your cash register Sharp up 700 it was that you mean the mode switch (a switch that look like a lock but its not, it is a rotary switch below the display that you have to use a mode key to choose the operation mode of your cash register).

If this is the case may I suggest that you unplug the power of your cash to make sure the lock do not short an electronic circuit inside.

This is a frequent problem on this model.

The mode switch (the true name of this part) was hold by only one screw in the plastic of the top cabinet of the cash.

And the way I put it back at his position is open the top cabinet and make a small hole in place of where the screw that hold the mode switch and fix it with a metallic screw and nuts and use locktite to make sure it does not unscrew.

I know it is not a nice repair but it is no use to glue the plastic that hold the screw it never strong enough to hold.

I warn you it is not an easy repair and if you unplug the top cabinet of your cash and you plug it back, the display of your cash may go blank.

You have to reset the cash (not a master reset) and program the date and time of your cash because the circuit that hold the time is on the top cabinet and the battery that energise the circuit is on the main board.

So, it is very difficult for a novice.

Good luck.