Power supply should output 24v to the inverter. If the voltage is not there or is low, disconnect the inverter and try again. If there is no voltage, the power supply is likely bad. If the inverter kills the 24v, it's either the inverter or the panel. If the voltage is low and fluctuating, it's the power supply.
You might also need to check back light on(bl_on) coming from the main board, should be 3.3v or 5v.