Again a bit of the same: open them only once and leave the cover off. Do what you want to do, listen and judge. When its finished you can screw the cover back on. Always seal the cdplayer with a cloth when not used and try to make this a one week job max.
There is an extensive explanation around here about what can be done with the Alpha 5 + ( and what not to do ). If you want to change the clock to a canned XO type I advise to make a shielding sheet of metal between the riser board and the DAC board.