e-studio 281c

[franc99]

Hi i have a e-studio 281c , at power on the display show this message :
Close front cover.
iI have check the front cover switch and the side cover switch whith test
03 power on . These switch are ok and the cover interelock switch is ok too. I have 120volt input to power supply but no 24v dc output.I change the power supply unit and i have the same message.
Somebody have a idea?
Thank!

[deep]

I suggest you to check the main PWB.