What I have here are three separate circuits All four connectors are actually ethernet jacks. The top two connectors connect to each other and the bottom two connectors connect to each other. connections are made via two 12-inch ethernet cables. All resistors in the circuit are 1Kohm, and the LED voltage drop is 1.8V-3.6V depending on the color I use but I believe I compensated for that by using 1K resistors instead of a lower value.

The circuit on the left controls both shift registers simultaneously and each shift register is supposed to get the same set of signals.

When I tested one of the two circuits on one connector slot, the shift register seems to be functioning. I then test the other circuit in the other connector slot and It doesn't seem to work.

I could assume it is the jacks at fault, but then again, I wonder if my resistor values are too low? There will be a point in which all lights need to go on at once.

Also, is it a bad idea that a staple (that I use for a jumper) is located under the RJ45 connector (above the circuit board).

I'm looking into replacing my connectors but if I can get a benefit from replacing the resistors, with higher value ones without losing significant brightness as well, then I'd do that too.

The LED brightness rating is at least 2000mcd

 

The resistors should not be the cause of the problem, since these are connected on the outputs. Maybe there is some trace which has not been soldered properly and the signal is corrupted.
Check it with an oscilloscope.

PS: I did not look at the DS of the shift registers.

 

ok I'll check connections including those on pcb. thanks