i did this years a go piked on up in cambrige at boot fair new in box at time other was asking brad from best computers to try to get them one from states
any way i cut a bit out of an well dead 600xl this was the osc that i needed plus then change gtia and any other atari custome chip for ther later version from xl/xe
haked in the nice littel bit of pcb to right places and chged mod was firs pal one tah did not need multistandars tv but most moder set should be mulit standra now