I've used PAL2GAL to do some conversions. Many times it works great but in some cases that isn't enough. You also need to watch for the speed and brand of the GAL. Helps to have a variety on hand. Had to make one for a memory decoder for a Z80A based processor and had to use a slower rated GAL since the faster one threw off the timing. As long as and original PAL image can be read I could try running a conversion.