NEED HELP!!!

[chixxx]

I'm building an air hockey table and i need a counter that will count to 7 then loop back to 0.I have this diagram which looks right to me but it only displays a 7. I reviewed my connections and they seem right and now im totally confused.So if anyone could take a look at the circuit and see if it looks right or even has any suggestions on how to fix the problem it would be a major help. Thanks Everyone!

 

[eblc1388]

Break the circuit into three functional parts and starts from the display section. Ground or pull high the A,B,C data pins of 74LS74 to see if the 7-segment display correctly.

Then applies high/low to the clock pin of 74LS93 to see that its BCD outputs changes accordingly.

Finally verifies that the photo-diode section correctly triggers the 74LS93.

 

[JimB]

I dont seem to be able to view your circuit, but if the copy by L Chung is the same as yours, the problem is in the reset circuit of the 74LS93.

The reset pins (2 and 3) should be held low during normal operation, a 10k resistor to 0v should be OK.
Connecting the reset to QD should reset on the 8th pulse.

You have pins 2,3 and 11 connected to Vcc. This may have killed the 74LS93. Putting Vcc into an output (QD pin 11) could have fried the chip.

JimB