I do not understand the sequencing of the second Hex Inverter inputs circled on this schematic. Aren't the inputs of a 7404 individual independent inputs? I initially wired them the second inverter 1,3,5,9,11 and it doesn't work! When wired as shown on the schematic it does work? What difference does it make what order the independent inputs are used??? Yes, I did use the correct output from the input for LED.

 

What difference does it make what order the individual inputs are used?

Should make no difference.
Define "doesn't work".
Are you sure you wired it correctly?

 

I do not understand the sequencing of the second Hex Inverter inputs circled on this schematic. Aren't the inputs of a 7404 individual independent inputs? I initially wired them the second inverter 1,3,5,9,11 and it doesn't work! When wired as shown on the schematic it does work? What difference does it make what order the independent inputs are used??? Yes, I did use the correct output from the input for LED.
View attachment 369018

When you initially wired that second inverter chip 1,3,5,9,11 did you also wire the outputs 2,4,6,8,10 ? (listing pins "downwards" on the diagram).

So long as pin 6 from the 7442 gets routed to LED 5 (and so on) it will work.

 

Doesn't work means the LEDS after the 5 from the 1st inverter did not light up in sequence correctly on my first try wired 1,3,5,9,11 on the 2nd inverter. It does light up in sequence correctly after I reverse ordered the second inverter as shown in the schematic? So, I am baffled what would cause that? I didn't think it would matter either, so I initially wired them 1,3,5,9,11 with no joy. Maybe I did wire the outputs as shown on the schematics the first time but indexed the inputs 1,3,5,9,11? That is the only answer I can come up with?

 

OK, I must have! Went and tried again with 2nd Inverter 1,3,5,9,11 and correctly wired the outputs and it works! Thanks guys!

 

I didn't think it would matter either, so I initially wired them 1,3,5,9,11 with no joy.

The inverters are independent of each other, but I once had a quad DFF on a ROM board in an HP 3000 Series III that only failed with certain input combinations.

Rewire as you did originally and swap the two 7404 to see if the problem goes away.

 

is that second inverter IC powered? check GND and 5V rails...

EDIT --- too late ;-).

 

? cold weld . . . ? n/c . . . ? n/c at power pins . . . as a function of time~instance-of-assembly

. . . https://www.eevblog.com/forum/projects/logic-ics-die-pictures/msg4277749/#msg4277749

 

I was puzzled when I first read the schematic as to why the 2nd inverter was wired in "reverse sequence". I guess it was to show that the sequence was nonessential as they are indeed independent!

 

or whoever made it was trying to optimize it for his board design. i always start with neat and uniform order but to make PCB simpler, often change it, specially for connectors and terminal blocks.
at any rate different order of inverters as drawn is not the reason for circuit to not work.