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Seven segment led scoreboard

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hi,
Look at this image, I have used the spare gate on the 4093 as an oscillator, about 1Hz.
Disconnect the existing wire to pin 12 of the 14553 and connect 4093 pin 4 in its place.
This should auto pulse the counter at about 1Hz, it will prove the if the debounce is the problem or not.:)

Greetings again; Thanks again. I have done as you suggested with the following results. When I power up the scoreboard the 2 digit led display flashes , however each segment of the display seems to flash at a different rate and at a different brightness. When I connect the test led to #9 on the 14553 pin it does flash. During this test, no buttons were pushed. Does this indicate that the schmitt is defective? Lorne
 
Greetings again; Thanks again. I have done as you suggested with the following results. When I power up the scoreboard the 2 digit led display flashes , however each segment of the display seems to flash at a different rate and at a different brightness. When I connect the test led to #9 on the 14553 pin it does flash. During this test, no buttons were pushed. Does this indicate that the schmitt is defective? Lorne

Hi,
If I follow what you say.
Pin 9 switches hi/lo [ led on/off] this suggest the counter ic is working on that pin, which it must do if we are to get odd numbers.

Are the digits flashing about a 1Hz rate.? and do you ever see a '1' on either display..??

The different flash rate dosnt sound right.?

EDIT:
I cant see it on your dwg, but you do have a +V on pin 16 of the 4543 ic.??
 
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Hi,
If I follow what you say.
Pin 9 switches hi/lo [ led on/off] this suggest the counter ic is working on that pin, which it must do if we are to get odd numbers.

Are the digits flashing about a 1Hz rate.? and do you ever see a '1' on either display..??

The different flash rate dosnt sound right.?

EDIT:
I cant see it on your dwg, but you do have a +V on pin 16 of the 4543 ic.??

EG All the led segments on the 2 digital display are flashing. Some segments are flashing so rapidly that they appear to be on while others flash at a slower rate. Some even seem to give a quick double flash.

Yes # 16 is to +V on the 4543. Also #1 is to +V on the 4543. Thanks for the quick response. Lorne
 
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EG All the leds on the 2 digital display are flashing at the same time.. Some segments are flashing so rapidly that they appear to be on while others flash at a slower rate. Some even seem to give a quick double flash.

Yes # 16 is to +V on the 4543. Also #1 is to +V on the 4543. Thanks for the quick response. Lorne

hi,
Are you sure you have a 1000pF [0.001] cap on the osc pins 3/4.

Ive cleaned up your dwg, added the ULN [ dont know what pins you use.]

You should be able to slow the 1 Hz pulser down by increasing the 10uF to say 47uF. for testing
 

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hi,
Are you sure you have a 1000pF [0.001] cap on the osc pins 3/4.

Ive cleaned up your dwg, added the ULN [ dont know what pins you use.]

You should be able to slow the 1 Hz pulser down by increasing the 10uF to say 47uF. for testing

Greetings The pins I use on the ULN are exactly as you show. Pin # 6 on the 4543 is also 0V. Yes I am sure that the cap is 0.001uf. Being a bit of a greenhorn I assume that 1 Hz is 1 pulse per second. By the way the test probe led on pin 9 does flash about 1 per second but all the display segments flash as I stated before. Lorne
 
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Greetings The pins I use on the ULN are exactly as you show. Pin # 6 on the 4543 is also 0V. Yes I am sure that the cap is 0.001uf. Being a bit of a greenhorn I assume that 1 Hz is 1 pulse per second. By the way the test probe led on pin 9 does flash about 1 per second but all the display segments flash as I stated before. Lorne

hi Lorne.
As the fault is obscure, I would suggest the following.

1. Disconnect the two 10K resistors from the 4553 pins 1 and 2.
2. Connect the first transistor 10K directly to 0V [ so the LEFT transistor is always ON]
and the other 10K to +V [ so the RIGHT transistor is always OFF]

3. Disconnect the four wires to the 4543, pins 5,3,2,4
4. Connect the four pins of the 4543, pins 5,3,2,4 to 0V [ this makes the input = to a "0"]

5. Now switch on the power to the pcb.

6. The left LED should display a "0" [ the right LED should be OFF/blank]

Tell us what you see.

If it does display a "0" ok then
7. Disconnect 4543 pin 5 from 0V and connect to +V via a 10K resistor.
The LED should now display a "1"

Tell us what you see.:)
 
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hi Lorne.
As the fault is obscure, I would suggest the following.

1. Disconnect the two 10K resistors from the 4553 pins 1 and 2.
2. Connect the first transistor 10K directly to 0V [ so the LEFT transistor is always ON]
and the other 10K to +V [ so the RIGHT transistor is always OFF]

3. Disconnect the four wires to the 4543, pins 5,3,2,4
4. Connect the four pins of the 4543, pins 5,3,2,4 to 0V [ this makes the input = to a "0"]

5. Now switch on the power to the pcb.

6. The left LED should display a "0" [ the right LED should be OFF/blank]

Tell us what you see.

If it does display a "0" ok then
7. Disconnect 4543 pin 5 from 0V and connect to +V via a 10K resistor.
The LED should now display a "1"

Tell us what you see.:)

Good morning EG; Just getting up and around here in Canada. After checking the truth table for the 14543 I understand what you are having me do. I will get back to you after I have done what you have suggested. Thanks again for taking the time and effort to help me get this project up and running. Lorne
 
Good morning EG; Just getting up and around here in Canada. After checking the truth table for the 14543 I understand what you are having me do. I will get back to you after I have done what you have suggested. Thanks again for taking the time and effort to help me get this project up and running. Lorne

OK EG here's the scoop. The digits display as expected. First test displayed 0. Second test displayed 1 on the left led digit display. Lorne
 
OK EG here's the scoop. The digits display as expected. First test displayed 0. Second test displayed 1 on the left led digit display. Lorne

hi Lorne,
Thats encouraging.

You could test the 2nd LED if required by swapping the 10K's over for the transistor base resistors.

OK.:)
 
hi Lorne,
Thats encouraging.

You could test the 2nd LED if required by swapping the 10K's over for the transistor base resistors.

OK.:)

EG Everything checks out good when I reverse the connections to the transistors. I get the 0 and the 1 on the right digital display. Lorne
 
EG Everything checks out good when I reverse the connections to the transistors. I get the 0 and the 1 on the right digital display. Lorne

OK Lorne.

Reconnect the two 10Ks back onto their pins of the 4553, so that they will drive the LED transistors as normal.

[Keep the the 4543 pins disconnected from the 4553.]

Repeat the 4543 pins 5,3,2,4 to 0V... the two LEDs should now both show "0"

if OK then
Disconnect 4543 pin 5 from 0V and connect to +V via a 10K resistor.
The LED' both should now display a "1"

Lets know.. :)
I can stick around for about the next 2 hours...if needed.
 
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OK Lorne.

Reconnect the two 10Ks back onto their pins of the 4553, so that they will drive the LED transistors as normal.

[Keep the the 4543 pins disconnected from the 4553.]

Repeat the 4543 pins 5,3,2,4 to 0V... the two LEDs should now both show "0"

if OK then
Disconnect 4543 pin 5 from 0V and connect to +V via a 10K resistor.
The LED' both should now display a "1"

Lets know.. :)
I can stick around for about the next 2 hours...if needed.

EG every thing checks out. both 0's, both 1's Lorne
 
EG every thing checks out. both 0's, both 1's Lorne

hi Lorne,
Just one more check, hang in there.;)

I would fully test the 4543 in the following way.

You have done the "0" and "1" 's

If you now connect the 4543 pins 5,3,2,4 as follows, high/low you can check every number from "0 thru 9", if they check out it will prove the 4543 is OK and the problem maybe with the counter.

pin 5 high [with a 10K to +V]
pin 3 high [with a 10K to +V]
pin 2 low to 0V
pin 4 low to 0V
This should give a "3"

then:
pin 5 high [with a 10K to +V]
pin 3 high [with a 10K to +V]
pin 2 high [with a 10K to +V]
pin 4 low to 0V
This should give a "7"

If these test prove OK, then I would suspect the 4553 ic.

As you are young fella it shouldn't take too long.:)
 
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Dont leave me hanging..Im curious if the last set of suggestions have helped out. MNow this is what I call a useful, and interesting thread, from a originally very cool circuit.
 
hi Lorne,
Just one more check, hang in there.;)

I would fully test the 4543 in the following way.

You have done the "0" and "1" 's

If you now connect the 4543 pins 5,3,2,4 as follows, high/low you can check every number from "0 thru 9", if they check out it will prove the 4543 is OK and the problem maybe with the counter.

pin 5 high [with a 10K to +V]
pin 3 high [with a 10K to +V]
pin 2 low to 0V
pin 4 low to 0V
This should give a "3"

then:
pin 5 high [with a 10K to +V]
pin 3 high [with a 10K to +V]
pin 2 high [with a 10K to +V]
pin 4 low to 0V
This should give a "7"

If these test prove OK, then I would suspect the 4553 ic.

As you are young fella it shouldn't take too long.:)

Hi Eric; I managed to test the 9,8,7, & 6 digits yesterday which checked out well. However due to unforeseen circumstances the project will have to be put on hold for a bit. I will get back to you when I proceed with the it. All this trouble shooting has been a great learning experience for me. Thanks again for your input. Lorne
 
Hi Eric; I managed to test the 9,8,7, & 6 digits yesterday which checked out well. However due to unforeseen circumstances the project will have to be put on hold for a bit. I will get back to you when I proceed with the it. All this trouble shooting has been a great learning experience for me. Thanks again for your input. Lorne

Hi Eric; Well I am back at the project again. The pins checked out ok on the 14543, so I installed a new 14553 IC and I still have the same problem. I have checked the capacitors "in the circuit" and they all seem to be ok. I have also checked the transistors "in the circuit" and they are ok. Is it ok to test these components in the circuit or should I take them out? The only difference that I see in the circuit from the first scoreboard that I made and this one is that the ground wire that I use for the common anode ground is a bit larger, but I didn't think this would make any difference. As I said before I have checked and double checked the circuit. Looking forward to hearing from you again. Lorne
 
seven segment led score board

Score board update. Recently I found out that a friend of my son has had experience in electronics so I contacted him to pick his brains regarding the problem that I was having. He came up with the following modifications to the CD4093 Schmitt Trigger that I have attached below. Along with some wiring changes the counter switches were changed to SPDT. I did the changes and the scoreboard is now working as it should. Hope this is of some benefit to anyone that is interested in this project. I have also attached a picture of the finished scoreboard.
 

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