the voltage on the RHS of the resistor should not be dropping off like that.
was there any corrosion under the capacitors when you removed them?
try doing this with the dmd display and driver boards disconnected:
Connect a 906 flasher lamp across the +5 and GND test points on the power supply and then test the voltages at the resistor
I am just trying to see how much load the +5v can take before it starts dropping off and I often use a 906 wedge flash lamp to determine this
