[SiriusHardware]

Now that RAM TEST looks like it's running, one thing you could try is something which Mark suggested earlier, remove all RAMs and put only one RAM at a time into the first RAM socket, see if you can identify individual good and bad RAM ICs that way. It's possible for one RAM to be so faulty that it affects the operation of the rest.

If this method identifies at least one RAM which always passes as good, try moving that one RAM step by step through all of the other RAM positions as a way of testing each of the RAM slots / positions individually. (There might be one particular slot or row in which no RAMs will work).