It is possible to change the region of an Anvil 3DO system by changing only two components. Which components need to be changed depends on model of 3DO.
Change X101 and add or remove a resistor at R10P. It is currently unknown if populating R10P works correctly. R10P connects VRAM S7 and ground.
A known functional PAL mod used a 47k? resistor placed between VRAM S60 (VRAM S6 after a 47 ohm resistor) and ground. The mod was not confirmed to be free of visual glitches.
The diagram on the silkscreen (located next to the access light) reads as follows:
|NTSC||49.09MHz Half Can||X|
|PAL||50.00MHz Half Can||O|