First, where is a good source of replacement chips? I have a ROM chip, controller chips, and the newer DRAM chips, but I haven't found a place that sells the others except for China on ebay. Also when you refer to D4 what are you referring to there.
If you were doing this what would you replace 1st? I can solder, but I was hoping to narrow it down some. Does the fact that the Expansion module work eliminate any of the chips you listed above. I appreciate all the help you have been. I have learned a lot.
Thanks,
Vgcollector