Help R.P.M. Meter Circuit

IMG


I get a test for R.P.M. Meter & four display 7 segment on circuit test panel.

It can't work, I am checking for so many times,

it haven't get any mistakes on connect segment.

No fan speed it only indicate four cero ( 0000 ) after electricity test.



P.S. On circuit web site IC 74C925,

it is very old no stock on market, therefore change to IC 74C926.

I follow the datasheet change the Pin for IC 74C926.

N1 / N2 I use IC 74LS14, can you provide the circuit to me.

I give a E-mail to circuit wet site station reply me no problem occur.

Please help me to solve this problem !!!

Looking forward to hearing from you

Sorry,

I am having a real problem following what you mean.
Could you post your circuits schematic. So if english isnt your 1st language and hare learning, we can still follow a circuit diagram and see if there are any mistakes

thanks