If the display shows the frequency it is set for, what is the problem? I really don't understand what you are asking.

I’m asking for a solution to the 5KHz and above glitch at the input of decade 5.

 

Here’s my work so far.
The problem counter is top center.
I removed the 7475 latch which for troubleshooting

 

Where are your 0.1μF ceramic capacitors?
I don't see any.

 

Where are your 0.1μF ceramic capacitors?
I don't see any.

Had the problem with the capacitors and without.

 

Had the problem with the capacitors and without.

That is not the issue. It is like wearing a seat belt. You don't see any effects with or without.
The point is, you can have 10 problems on the board, fixing one problem shows no difference.

 

That is not the issue. It is like wearing a seat belt. You don't see any effects with or without.
The point is, you can have 10 problems on the board, fixing one problem shows no difference.

Good point.
I’ll re-install the caps.
I’m working to post a full schematic.
It was mentioned if I draw the entire circuit, I could find the source of the problem.

 

It was mentioned if I draw the entire circuit, I could find the source of the problem.

More importantly, it would allow us to give you meaningful troubleshooting suggestions.

 

More importantly, it would allow us to give you meaningful troubleshooting suggestions.

Thanks fellas.

 

Designed a counter using LS circuits.
All was going well up to the last decade.
The circuits track the frequency as designed to 5KHz.
After that the last stage output sends a pulse to the fifth once every four gate times.
Lower the frequency, the pulse stops.

I am assuming you are using the counter as a binary counter and not a BCD counter.
If you are looking at the output of QD, you will see a low pulse on the count of 4 and 9 (see the truth table attached).
Are you sure the circuit is counting the way you expect it to? I rather doubt it. Did you design it or is it from a source on the internet?

 

I am assuming you are using the counter as a binary counter and not a BCD counter.
If you are looking at the output of QD, you will see a low pulse on the count of 4 and 9 (see the truth table attached).
Are you sure the circuit is counting the way you expect it to? I rather doubt it. Did you design it or is it from a source on the internet?
View attachment 199008

I use the LEDs to save board space.
I can read a binary number as easily as I can a decimal number.
The counters are decade counters.

 

I use the LEDs to save board space.
I can read a binary number as easily as I can a decimal number.
The counters are decade counters.

You have LEDs in your circuit?
What is driving the LED?

Do you know that you cannot drive LEDs and take a logic signal from the same output pin?

Here is another reason for paying attention to datasheets.

 

It looks like the LEDs are being driven by LS374 and HC374:

 

You have LEDs in your circuit?
What is driving the LED?

Do you know that you cannot drive LEDs and take a logic signal from the same output pin?

Here is another reason for paying attention to datasheets.

Why has the first four decades not been affected?
I’ve been doing it for years without problems.
The resistor I used drops the LED current to about 10mA.

 

It looks like the LEDs are being driven by LS374 and HC374:
View attachment 199009

True.
This should not create the pulse glitch at counter 5.

 

I’ve been doing it for years without problems.

It looks like you're using #24 wire. I've found that anything smaller than #22 has a tendency to pull out when nudged.

I have an LED cube prototype that I've been running for a year or so. Every once in awhile, the multiplexing become erratic and I need to wiggle some wires to restore correct operation. Those wires are using male DuPont connectors that have a snug fit in solderless breadboards.

 

It looks like you're using #24 wire. I've found that anything smaller than #22 has a tendency to pull out when nudged.

I have an LED cube prototype that I've been running for a year or so. Every once in awhile, the multiplexing become erratic and I need to wiggle some wires to restore correct operation. Those wires are using male DuPont connectors that have a snug fit in solderless breadboards.

True.
Yes, I do have the nudged wire problem.
That’s why the first thing I do is check for it and a diagonally shifted wire.
This can reach across to the next row and create weird problems.
My protoboard is several years old now.
Some of the places are to loose for the #24 wire so I have to move the wire to another place in the row or move the device.

 

Why has the first four decades not been affected?
I’ve been doing it for years without problems.
The resistor I used drops the LED current to about 10mA.

Another common response: "I’ve been doing it for years without problems."

Did I tell you about the house painter who had been climbing the same ladder for 35 years?
"I’ve been doing it for years without problems."

 

Another common response: "I’ve been doing it for years without problems."

Did I tell you about the house painter who had been climbing the same ladder for 35 years?
"I’ve been doing it for years without problems."

We’re moving away from the issue.
None of the above comments are relevant to the 5KHz pulse glitch.

 

There are too many things wrong with your circuit.

Did someone not tell you that you cannot mix 74LSxx with 74HCxx?

 

Some of the places are to loose for the #24 wire so I have to move the wire to another place in the row or move the device.

Using #22 wire and not abusing the sockets by installing things that are too large (TO-220 leads, #18 wires) will give more trouble free operation.

I have some breadboards from Ali Express that have quality control issues. Most complain about insertion being too difficult because the metal strips don't align well enough with the plastic. My problem has been weak grip, so #24 wire can be problematic.

The breadboards for my cube are from the 70's and are good quality.