Need help for basketball scoreboard (double digit up/down counter)

[patrick_marin]

rewired

sir i rewired the circuit and got 0 0 initial display.. i made a 5v power supply thru 7805.. the problem is, the switches wont work..

 

[ericgibbs]

sir i rewired the circuit and got 0 0 initial display.. i made a 5v power supply thru 7805.. the problem is, the switches wont work..

hi,
I posted this yesterday, please do these tests and let me know the results.

OK.
Connect the cathode of the LED [thats the Bar] to 0V on your pcb.
Connect the 470R to the Anode of the LED, at the other end of the 470R connect a short piece of insulated wire, about 10inches should be OK.

Bare about 5mm of the wire end.

Power up the PCB, you can now use the wire end to test different parts of the PCB.

If the voltage is +5V the LED will light bright, if low it will not light.

Test the voltages [using the LED wire] and see what the 74LS14 pins # 4, 8 and 10 show,,, let me know.

EDIT:
Test these points.

Look at this image, test the points I have noted.

 

[patrick_marin]

hi

sir eric, i want to express my sincerest gratitude to you, for helping me through my project.. it is now working, but when it reaches 30-39, the segment "E" for the tens digit lights up too..

how can we fix this?

 

[ericgibbs]

sir eric, i want to express my sincerest gratitude to you, for helping me through my project.. it is now working, but when it reaches 30-39, the segment "E" for the tens digit lights up too..

how can we fix this?

hi,
Well done, pleased to hear you are making progress.

If I understand you correctly about the tens 'd' segment, its supposed to be lit for the number '3' tens.

Could you explain what you mean,?

EDIT:
just seen your edit, you meant 'e' segment.

Disconnect one end of the resistor that goes to pin 9 of the tens... see what you get.

 

[patrick_marin]

sir you mean pin 9 is the segment for 'f'?
**broken link removed**

 

[ericgibbs]

sir you mean pin 9 is the segment for 'f'?
**broken link removed**

No, I mean pin 9 of the 74LS247.

 

[patrick_marin]

No, I mean pin 9 of the 74LS247.

ok sir, sorry for that, so that will be a direct connection from 7447 to CA? ive done it sir, still the same..

 

[ericgibbs]

ok sir, sorry for that, so that will be a direct connection from 7447 to CA? ive done it sir, still the same..

No, dont direct connect it.!!

Keep pin 9 of the 74LS247 disconnected, then segment 'e' should not light at all, if it does you have a shorting link, check the wiring to the 'e' segment.

When you have disconnected pin 9, switch on the project and press the UP count button, if the tens 'e' lights you have a wong wire or short circuit.

 

[patrick_marin]

understood sir, yes segment 'e' is not lit when disconnected..

 

[ericgibbs]

understood sir, yes segment 'e' is not lit when disconnected..

Just to make sure, you are saying as you count from 00 to 99, segment 'e' on the tens never lights up while pin 9 of the 74lS247 is disconnected.??
Let me know.

 

[patrick_marin]

yes sir, its turned off during the process

 

[ericgibbs]

yes sir, its turned off during the process

OK,
That indicates that you either have a short across the pin 9 of the LS247 or the LS247 is faulty.

Check around pin9 for short circuits etc.

I assume it does count from 00 to 99 OK.???

EDIT:

pin 9 [e] is next to [d] which is pin 10, I think pins 9 and 10 are shorted together, double check that.!

 

[patrick_marin]

ok sir, maybe rechecking of the connections is just the answer to this, also checking for shorts. yes earlier its counting from 00 to 99 and v.v, but now its not, maybe my battery is low already..

anyway sir eric, it gives me comfort knowing that i found an answer to my project, through you..

 

[patrick_marin]

hi

sir i rewired everything, double checked and done the test using LED for the test points.

point 4, 8, 12, are ok. LED is lit.

point 10 is off.

but the switches are not responding again.

what am i going to do? before i had it worked to count from 00-99, the only problem was the 30-39 tens digit, segment E is lit which is supposed to be not.

 

[ericgibbs]

sir i rewired everything, double checked and done the test using LED for the test points.

point 4, 8, 12, are ok. LED is lit.

point 10 is off.

but the switches are not responding again.

what am i going to do? before i had it worked to count from 00-99, the only problem was the 30-39 tens digit, segment E is lit which is supposed to be not.

hi.
ok, dont panic!

1. Connect the test LED to pin #4 of the 74LS14, the test LED should light, now push the UP button, the test LED should go dark.


2. Connect the test LED to pin #8 of the 74LS14, the test LED should light, now push the DOWN button, the test LED should go dark.


3. Connect the test LED to pin #10 of the 74LS14, the test LED should light, now push the CLEAR button, the test LED should go dark.

Let me know exactly what happens when you do this test.

 

[patrick_marin]

hi.
ok, dont panic!

1. Connect the test LED to pin #4 of the 74LS14, the test LED should light, now push the UP button, the test LED should go dark.


2. Connect the test LED to pin #8 of the 74LS14, the test LED should light, now push the DOWN button, the test LED should go dark.


3. Connect the test LED to pin #10 of the 74LS14, the test LED should light, now push the CLEAR button, the test LED should go dark.

Let me know exactly what happens when you do this test.

hi sir

test point #4, UP button pressed, LED OFF
test point #8, DOWN button pressed, LED OFF
test point #10, CLR button pressed, LED ON

sir as you said earlier, on pin 10, LED should be off?


**broken link removed**

 

[ericgibbs]

hi,
That part is working OK.

Now do this check using the test LED.

Test ALL pins 16 of the LS192 and LS247's for the test LED ON [that the +5v supply to the IC's]
and
ALL pins 8 for the LED OFF. [thats the 0V supply to the IC's]

Let me know.

 

[ericgibbs]

hi,
When you have done the pins 8 and pins 16 test, look at this image and do this test.

 

[patrick_marin]

hi

hi,
That part is working OK.

Now do this check using the test LED.

Test ALL pins 16 of the LS192 and LS247's for the test LED ON [that the +5v supply to the IC's]
and
ALL pins 8 for the LED OFF. [thats the 0V supply to the IC's]

Let me know.

all ic's has power, LED is on when its connected to pins 16 & 8 of every IC.

 

[ericgibbs]

all ic's has power, LED is on when its connected to pins 16 & 8 of every IC.

I think you mean the test LED is OFF when connected to the #8 pins, I hope!


EDIT:
Now do this test.