hello mister_rf
I really haven't had the chance to look into the schematic on the weekend but, I briefly took a try on the above late Friday night ignoring Inputs A, B, C, D (pins 15,1,10,9).
I had a weird result not giving me the proper counting. It is still only giving me 6, 7 and 8. When I press the switch B1, it should give me count #1 after pressing the reset button (displaying no. 8 figure) but it goes to seven right away and when you press the switch again, the LEDs blinks and when you press B! one more time, it displays the no. 8 figure but couple of the segments dims a bit.
Same scenario as B2. I've also experimented moving the +V line from the 7 segment and connecting it to the output of the LM7805 volt regulator and it give's me a default no. 2 when i press teh preset button B3. And when I press B1, it gives me a no - 5, 4, 6 or 9. B2 give's me no. 7, 3 and 5.
I checked all connections between the 74LS47 and 74HC192 are correct based on what you have given.
So, for some reason, it's coding it wrong. Is it possible, the two IC's not compatible or should I use a BCD counter?
Please advise ASAP.
I appreciate it very much.
barbaro