Do you think this is a guaranteed fix? I sort of dislike the shotgun approach to fixing things, but I guess it's worth a try.
The green screen means that the power on write then read test to memory has failed, which doesn't always mean that there is an issue with the memory ICs. Can also be related to anything that shares the memory bus. You can probably do some more tactical fault finding if you have an oscilloscope and the skills to use it.
Another quick thing to try is exchanging the two 8520 CIAs. I've seen faults where one of them being bad, I forget which one, causes a green screen error.
