Problems with digital clock

[tphebert]

Hello,

I builted a ttl digital clock, using 7490's, 7492's, and 7447. Its a 24 hour clock and works great. The only problem i am having is with the set switches. My first switch to turn the frequency , which is 1 hz, on and off to the clock works fine. The second switch is connected to the 1hz and the output is connected to the minutes 7490 Qa. The third switch is connected to the 1hz and the output is connected to the hour 7490 Qa. The minute switch when turned on will count to 5 the go to zero and then stay on zero. The hour switch will count to 3 go to zero then stay on zero. Will a capacitor help this problem,i haven't tried this yet.

 

[RODALCO]

TTL clock problems

Post us your diagramme.

It could have to do with no pull up or down resistors. reset and set TTL gates like to know what to do.

 

[tphebert]

I can have it up in a couple of days. Thanks i'm in the process of drawing it now.

 

[BeeBop]

I think your problem may be switch bounce, but I'll wait until you post your schematic.
Anyway, I see you got your question posted.

 

[tphebert]

Thanks Beebop

I'm looking in my book and that makes perfect sense. I'll try it Monday. Thanks

 

[BeeBop]

OK, keep us posted.

 

[tphebert]

Thanks

I made my schematic today, but my friend accidently picked it up. i'm trying to see if she can email it to me. I worked all day on it.

 

[dprasad]

hey you wouldnt happen to still have the schmatic do you?Ω

 

[Diver300]

The OP last signed in 4 years ago. You could try a private message.