Originally Posted by
jpawelk
My guess is that something is dragging the power down.
Start by removing the AMP style(black, round 14 pin) FPP connector on the control box to see if you voltage comes back. If voltage comes back there is a problem with the front panel.
If power is not affected by removing the FPP, disconnect the AMP style POWER connector from the control. If the power comes back, then there is something wrong with the control or an input that is dragging it down. To determine which one, install the POWER connector and then start removing all the input AMP connectors. Determine which connector, when connected, is dropping your power.
If all of that does not help, start removing wires from TB12 while monitoring VDC between TB12 and TB22. If there is a shorted wire, you will regain the full 24VDC when its removed from TB12. Trace the wire to the problem.
Good luck!