Kinda hard to tell the 'backside' of one circuit board looks pretty much like anyone else's.. I would note that you don't appear to have any by-passing installed and that "can" cause many different issues to crop up, including ones similar to if not identical to yours especially with shift registers.Bob
Also, would this happen to have anything to do with it remember the last state the shift register was in, per http://arduino.cc/en/Tutorial/ShiftOut ?
Possibly and more to the point, If the board doesn't have (at least) a 100 nF cap from +5 V to ground right on each IC the board 'can' count itself or count the noise on the + 5 V source at the shift register. I am assuming that the other pins are either pulled up or grounded as per the tutorial and that the capacitor shown on the '595 shift register tutorial diagram IS NOT installed.The tutorial is a good one except that it doesn't show the missing capacitors.Bob
QuoteAlso, would this happen to have anything to do with it remember the last state the shift register was in, per http://arduino.cc/en/Tutorial/ShiftOut ?That tutorial has a 1uF cap wired to the latch pin, this is wrong.You don't have to remember the state of the previous values in the shift register because it is over written by the shift out.
pin 1 on the shift register lost its wire
Quotepin 1 on the shift register lost its wireI am afraid that that is not the right fix, because it is in direct conflict with our experts' advice (on bypassing).Your fix doesn't count.:)Seriously, congratulation on your fix. You learned a lesson about wiring.