Encoder & Decoder Application

[he11fire]

I need help to finish this circuit design...The 7-Segment Display output is wrong for every button pressed...There's a relation between button 6 and 9 outputs, because the output of Display after button 6 is pressed is 9, and when I press button 9 the output is 6...I would really appreciate any help.
**broken link removed**

 

[ericgibbs]

hi,
The 74HC147 outputs are active LOW, so when I1 input is low, 'A' is LOW and B,C,D are HIGH, so the 74LS47 input is 1110, which is decoded as '14'
ie: d,e,f,g are are lit.

 

[he11fire]

so you are saying i should invert all the inputs of 74HC147?

 

[ericgibbs]

so you are saying i should invert all the inputs of 74HC147?

That would be the easy way, say a 74HC14 or similar

 

[he11fire]

I put 9 inverters after each push button and no LED lighted ...so I think this part is ok...

 

[ericgibbs]

I put 9 inverters after each push button and no LED lighted ...so I think this part is ok...

Do you mean its working correctly.?

EDIT:
The inverters should be on the outputs of the LS147 to the LS47 inputs.

 

[he11fire]

yes thats right ...i fixed it before but thanks anyway

 

[he11fire]

Do you know why 6 and 9 are not shown complete ?
I mean segment D at 9 isn't activated .
And segment A at 6 isn't activated either...

 

[ericgibbs]

Do you know why 6 and 9 are not shown complete ?
I mean segment D at 9 isn't activated .
And segment A at 6 isn't activated either...

Its the decoder LS47, see this image