Remember this rule - Leave no input pin not connected. In other words, input pins must be connected to a proper logic level voltage.

Pin-15, CLK is an input pin. What are you going to do with that? Connect it to pin-15 of the previous counter.

Since RST, pin-9 is active HIGH, connect it to GND to disable RST (or connect it to pin-9 of the previous counter).

Thanks. It works perfectly! Now to wire up the other four digits.
M

 

I have now added a third digit to the counter circuit. As luck would have it, the third digit doesn't
work at all but one and two work fine. I have checked the wiring multiple times and I believe that
it is correct. I swapped out the CD4510, the CD4511 and the display with those in the second stage.
All ICs work. I checked the voltages on CD4511 and they are correct. I have no idea what to do next.
Note: I have disconnected all segments except for "e" so that the photo is easier to view.

Help!

M

 

I have now added a third digit to the counter circuit. As luck would have it, the third digit doesn't
work at all but one and two work fine. I have checked the wiring multiple times and I believe that
it is correct. I swapped out the CD4510, the CD4511 and the display with those in the second stage.
All ICs work. I checked the voltages on CD4511 and they are correct. I have no idea what to do next.
Note: I have disconnected all segments except for "e" so that the photo is easier to view.

Help!

M

Show a schematic.

 

Show a schematic.

Here is a schematic for the 2-digit version. The hundreds digit is wired identically
to the tens digit. Pin 1 of the CD4510s is grounded, contrary to what the schematic shows.

 

Here is a schematic for the 2-digit version. The hundreds digit is wired identically
to the tens digit. Pin 1 of the CD4510s is grounded, contrary to what the schematic shows.

I may be wrong, but it looks to me as if pins 1 & 16 on the leftmost counter may not be inserted into the breadboard?

 

I may be wrong, but it looks to me as if pins 1 & 16 on the leftmost counter may not be inserted into the breadboard?

Hi Sarah:

Thanks. Yes, that IC was pooched. I replaced it after the pic was taken. Good catch.

M