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the great race completed but only 1 problem.. look at my vid

Posted: Sun Sep 16, 2012 5:10 am
by nodoubtman
Hi! I have completed the great race, but there is a problem, here's the video.
Can you guys tell me what is the pin of the 7442 has problem?

thank you!
marC:)

video link : http://www.youtube.com/watch?v=8-016DCC ... e=youtu.be

Re: the great race completed but only 1 problem.. look at my

Posted: Sun Sep 16, 2012 9:13 am
by brad
It looks as though you have something shorted. You shouldn't have any RED led's lighting up on that second bottom row.

Have a good look at your circuit to see if you can find some shorts.

Re: the great race completed but only 1 problem.. look at my

Posted: Sun Sep 16, 2012 9:49 am
by nodoubtman
brad wrote:It looks as though you have something shorted. You shouldn't have any RED led's lighting up on that second bottom row.

Have a good look at your circuit to see if you can find some shorts.
what is the output of the 7442 to lit up the second bottom row??
so i can see if something is shorted.. in there

thank you!
marC:)

Re: the great race completed but only 1 problem.. look at my

Posted: Sun Sep 16, 2012 8:39 pm
by brad
I'm not sure exactly what you mean but are you referring to the logic level coming out of the 7442? Because there will be a logic 0 coming out of the 7442 each time it is enabling one of the rows of cathodes.

I would just get a multimeter (on resistance setting) and check for any short circuits between the matrix pins.