First, carefully double-check your repair. Use plenty of light and a magnifying glass, as well as an ohmmeter as necessary.
Also, what is pin 1 of the DRAMs connected to (I haven't looked at my 128K schematic and I don't remember the answer off the top of my head)? If it's floating, I recommended grounding it. The 4164s don't use it, but it's the higher-order address line for the 41256, and shouldn't be left floating.
And as I mentioned earlier, the memory self-test is very crude. It's not able to distinguish between a true memory failure and one that's due to other causes. Since it is very rare for multiple DRAMs to die spontaneously, you should suspect something else if, say, one more memory chip replacement doesn't fix your problem.
Good luck!
Also, what is pin 1 of the DRAMs connected to (I haven't looked at my 128K schematic and I don't remember the answer off the top of my head)? If it's floating, I recommended grounding it. The 4164s don't use it, but it's the higher-order address line for the 41256, and shouldn't be left floating.
And as I mentioned earlier, the memory self-test is very crude. It's not able to distinguish between a true memory failure and one that's due to other causes. Since it is very rare for multiple DRAMs to die spontaneously, you should suspect something else if, say, one more memory chip replacement doesn't fix your problem.
Good luck!