If you remove the power supply, usually you have to remove the separate readout board, alongside the powersupply.
Usually I remove the readout board before removing the power supply.
It happened to me once that I misplaced the flatcable connection from the readout board to the A1 board when putting it back in :-(
You do have the separate readout board? (if you have the SMD version of the A5 board, the readout functionality is integrated on the SMD A5)
Just my two cents,