So I'm going to swap out my system 3 mpu today and I have a couple of questions due to the difference between the two boards I have. The mpu will be going into a Williams contact and the replacement board came from a world cup. The main difference I see is the location of where the game ROM and socket are located on each board, and the absence of the 7813 chip on the contact mpu. On the donor world cup mpu the 7813 chip is all the way to the left in the picture, on the contact mpu its not there at all.So would I be correct in assuming that I have to move the game ROM and socket over to the open spot on the donor mpu and just remove the 7813? I should also put a diode under the ROM socket, correct? Thanks all!

The pictures...

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