Great, so CON1 is fully supplying the board with +5V from the Core regulator.
J89 only extends the shift register chain and doesn’t supply power in the same way. You might be able to put a scope or logic probe on the others to see if anything is coming through. In the picture above, the two left-most should show a pulse or state change that follows a burst of clock data, which are on the next set of two to the right. The middle pins transmit the serial data, with the upper pin for the outputs (= LEDs) and the lower for the inputs (switch activity on this board).