Code Lock K6400 - Input Code too short

I managed to solder the code lock and put it into position at a wall to open a door. It worked with my chosen 4-digit password. But after a while I realised that the door opened allready after the third (3.) digit. That means in fact that the security is downsized. The door is in a public area.

What goes wrong with the code lock? Help is very appreciated.


Perhaps I could not really point out my problem: my password has 4 digits. When I key in the code, the K6400 unlocks the circuit already after the 3. digit. It is not necessary to press the fourth number. The door opens premature.

It reduces the security to 2^3 possibilities. And that can be dangerous.

Does anybody know, what’s the catch with it?


Sounds like an assembly error.
Could you post a picture of the boards (top and bottom)