Troubleshooting 74LS90 Counting Issues: Using Input Pulses from a 555 Timer

[David lopez]

I am trying to use the 74ls90. It won't change it's output. It suppose to count to 9. The input
Pulses come from a 555 timer.

 

[Baluncore]

1. Have you got a 5 volt regulated supply?
2. Have you tied all 9_set and 0_set pins low. Pins 2, 3, 6 & 7.
If you let more than one of each float high it will lock the counter.
3. Which clock are you using as the input from the NE555.
4. Have you tied the output of that counter to the other clock input?
We are not long range mind readers.
Please provide a link to your circuit or;
Draw your circuit diagram and drag it onto your next post.

 

[David lopez]

I am using a 4.1 volt supply. is that two
Low?

 

[Baluncore]

It may work on 4.1V sometimes, but you should regulate Vcc between +4.75 and +5.25V.
Use a 7805 regulator to provide the +5V supply from a voltage above 9V.

Vcc above +6 volts can destroy inputs. If it is ever possible for the supply voltage to rise above 6 volts, then you must not connect TTL inputs to the positive rail without a 1k series resistor to limit the damage.

 

[David lopez]

A higher voltage does not seem to be
Working.

 

[davenn]

A higher voltage does not seem to be
Working.

Again, as in your previous thread ... I will ask for your circuit and photo of your construction

PLEASE do not again leave us all guessing as we try and help you

 

[davenn]

The input
Pulses come from a 555 timer.

Ohh and since you didn't seem to get your timer circuit working properly
it's no surprise that the counter isn't working properly

 

[berkeman]

Again, as in your previous thread ... I will ask for your circuit and photo of your construction

Agreed. @David lopez -- does your circuit look like this?

https://www.electronics-tutorials.ws/wp-content/uploads/2014/05/cou29.gif?fit=403%2C184