AESP is an output, it is high for normal service. It goes low if AESS input goes goes low. You said you replaced the Power Supply Board. I would try another Power Supply Board. It is not unheard of to have an after market board bad out of the box. If you made ESB high that is the same as resetting the Fire Service with the Hall Station Key. You may have 1 or more bad input or output boards.
