Debugging the 74HC595 Shift Register PCB

Over the last couple of days I spent the time to debug a PCB that works as a breakout board for two 74HC595 IC’s. How it works is the user can specify computer input or manual input through switches, and then toggle the serial data lines, output enable lines, and all of the inputs that the shift register needs. From there the outputs LEDs are supposed to turn on based on what the input data is. However, when debugging I found multiple errors as to why the board was not giving me the correct outputs, first, some of the LEDs were popped. I also found some of the SMD resistors to be broken/missing. However, when looking at the test points for the outputs I found that no matter what sequence of inputs I put into the serial in, the outputs are always high, as long as there is atleast one high serial in pulse. So now I believe the problem lies in the actual connections that come before the output of the shift registers, and I am starting to suspect that it is the connections going to the input signals of the IC that are causing the problem.