7 Segment Display Skipping Randomly *NO CODE*

Other Hardware General Electronics
1

This is my first circuitry project, and I'm trying to build a 3 digit 7 Segment display counter to be operated by pushbutton. I am using only IC chips (74LS47 BCD-to-7 Segment Decoder and Driver, and 74LS90 Decade Counter) to avoid coding anything. I've started with a single digit to test out the circuit and so far so good (the display is bright, the numbers count in the correct order, nothing heats up), except that it skips numbers occasionally with no discernable pattern.

I'm working off this tutorial:

So far I've tried changing out the switch, and the decade counter, as well as double and triple checking all connections. Any suggestions or help would be greatly appreciated!

2

I think that we need a schematic of your wiring. Hand drawn, photographed and posted is fine. Include all pin names/numbers, components, their part numbers and/or values and power supplies.

Clear photos of the wiring are often helpful.

What is the clock source for the decade counter?

3

Do you have any debounce circuit on the push button?

The page you linked to is only a tutorial, lacks complete circuitry, and doesn't mention any counter or button at all.

I also hope you have employed bypass capacitors on all the IC's.

4

I think reading the forum guidelines for posting would be a good thing to do.

5

Sorry about the missing information, I am just starting out. It looks like I linked the wrong tutorial, here's the correct one. I'll have to upload my wiring separately as I am only allowed one piece of media per post as a new user.

6

IMG_1703.HEIC
IMG_1703.HEIC3024×4032 3.42 MB

7

IMG_1702.HEIC
IMG_1702.HEIC3024×4032 3.43 MB

8

Debouncing the push button sounds like its just what I need, I'll give it a shot, thank you!

9

With TTL logic, it works best if the button pulls an input pin down to ground.

10

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