User talk:Y4ee 807

Iam constructed a counter 6-digit BCD counter for counting revolutions of motor.6-digit BCD counter is a modify version of 8-digit BCD counter that can be found on the MC14553B data sheet.Pboblem is that the display will not show the correct answer.It would do one of the following: 1. only one display counts correctly, usually the LSB or the MSB, 2. two of the displays show the same numbers, or 3. the displays show random numbers.

It has something to do with timing in the area where the MC14553 scans between the displays and shows the correct information on the correct displays (i.e. external oscillator, transistor switching). I've tested DS1-3 (pins 1, 2, & 15) and they should be scanning at a high frequency (oscillating) but they aren't.

Also all of the digits are inverted (segments that should be lit aren't, and visa versa). But that can be easily fixed.

I've tried everything I could think of, even built a second 3-digit counter, but I still come up with the same problem. Both circuits are built on veroboard.