JK Flip Flop Not Counting Properly in Actual Circuit

[AilingLore21]

Homework Statement

Hello everyone. I tried practicing creating up down counters using the J/K FF. I've been using the Synchronized Clock with an up down counter and the simulation seems to be successful based on this circuit on the image



However, in the actual circuit in a breadboard using a 74LS73 IC, a 555 timer with the capacitor and resistors, and an 74LS86, it somehow lags after counting to the max and sometimes refuses to count further for a few seconds . For example, after it successfully counts up to 3, it doesn't go immediately to 0 and instead goes to 2 and goes back to 3 again until it snaps out of it. When it counts down to 0, it refuses to go back to 3 and vice versa. It still counts up and down based on the switch but I don't know what's the problem with this.

The asynchronous 3 bit down D counter works very well in the breadboard. I wonder what's causing this? An IC problem perhaps?

Homework Equations

N/A

The Attempt at a Solution

[/B]

 

[Inventive]

I can't tell from the drawing, but is the flip flops clear pin tied high?