[amsat-bb] G5500 change voltage supply

I have purchased a G5500. The control box have a 117Vac label in the real panel. I opened it and a wire is connected through the fuse to the terminal number 3 of the KT-30 transformer and the other wire through the main switch to the terminal number 1 of the KT-30 transformer.

I am wondering how I should connect it to work with 220Vac in Europe.

Thanks in advance. ea4cyq@amsat.org