Time to get out the multimeter and start checking traces. With the exception of maybe 4 lines, all the lines on the 4264 RAM Chips are connected to their neighboring chips in parallel. So all the first row chips are connected together and all the second row chips are connected together and a majority of chips in Row 1 and Row 2 are connected to together.
This diagram shows that all but 2 or 4 pins should be connected together. Pins 2 (Data In), and 14 (Data out), with possibly Pins 4 (/RAS), and 15 (/CAS) should not be connected together. All the other pins should be connected. When they check out OK, follow the traces to the connected chips and test their connections with the multimeter. They should be OK.
Other than that, the only thing to do is to test the actual chips outside of RAM. I would guess following the suspected RAM Chip Data In/Out Lines to where they go and check their traces. If OK then those chips might be at fault. Without an oscilloscope it is hard to determine. Only Uniserver and/or TechKnight would be able to help out at this point.
This diagram shows that all but 2 or 4 pins should be connected together. Pins 2 (Data In), and 14 (Data out), with possibly Pins 4 (/RAS), and 15 (/CAS) should not be connected together. All the other pins should be connected. When they check out OK, follow the traces to the connected chips and test their connections with the multimeter. They should be OK.
Other than that, the only thing to do is to test the actual chips outside of RAM. I would guess following the suspected RAM Chip Data In/Out Lines to where they go and check their traces. If OK then those chips might be at fault. Without an oscilloscope it is hard to determine. Only Uniserver and/or TechKnight would be able to help out at this point.