hello…
I have a problem with the K6400 after input 3 digits relay is already open,this happens before I enter the real numbers type some other characters, and after 3 right digits the relay its already open, than its this only 3 digits code! …
Most likely an assembly problem.
If you post hi-res and sharp pics of both component and solderside, we can take a look.
hello! here are the images img185.imageshack.us/i/080101132128.jpg/
Soldering looks rather poor.
Pictures are not very sharp but most likely there are some bad solderings, especially at the IC.
We also notice that you have put a wire between base and keyboard. This can lead to troubles due to interference pickup.
I solved the problem! The problem was too long cables