When you have the click - click problem what happens is that the +8 volt regulator feeds the front panel unit with power and in the panel there is a 5 volt and a3.3 volt regulator that will burn out the resistor that feeds that 8 volt reg on the main board.
The CPU on the main board turns on the 12 volt relay and it has a few seconds to get the response from the CPU in the control head.
You have to have power the the CPU to activate the power relay.
IC 101 and IC 151 for the 5 and 3.3 volt in the control head.
If the 8 volt regulator is on line (no burned resistor) and you have 9 volts to the control head then check for the 5 and 3.3 volts on the board.
No voltage on the board the CPU cannot generate the data signal to the main CPU.