Keypad's seven segment display always shows a six

[JPlaxa]

Hello, I'm a student of renewable energy engineering and I have a problem with a circuit I've made. This circuit consists on a 0-9 keypad connected to a 74HC147, which is connected to a 4511BD, which is then connect to a seven-segment red display, with a common cathode.

The problem is that it doesn't matter which button of the keypad I press, the display always shows a six.

I've ran out of ideas and I don't know why it doesn't work as it should. 

I would be very thankful if someone could help me out, I'll leave the ms11 file here. Thank you.

[aa232004]

hello, I have it checked.

a few things -

what is the purpose of s1?

why do you use NC buttons instead of NO?

what is the purpose of that module?

why do you use priority encoder?

as it is it works OK - just check data sheet of 74147 and look at true table.

good luck

Michael

[JPlaxa · Accepted solution]

I've already solved it, I just had to replace those NO buttons witj NC buttons and had to add a few NOT gates next to the 74147.
Thank you, nevertheless.