DRAM Coreboard repair. Advice sought

[MbeeTech]

Wow. It boots! I'm not completely out of the woods yet. I think I might have some bad RAM somewhere. Why? If I choose "Word Processor" I get:
[Photo of Simply Write not looking as it should] 

Simply Write (the word processor) needs to run on a Premium Series (or 256TC) Microbee with the extended PCG graphics banks.

The square symbols etc on the screen are actually supposed to be values that get written to the Attribute ram in the Premium / 256TC graphics
system that is not part of a standard Microbee.  The Attribute ram tells the system (among other things) which bank of PCG ram to reference at that 
character cell on the screen.  If there is no Attribute ram in the system (in the case of a non-premium machine) the data that was meant for the
attribute ram ends up in normal screen ram, at which point you see that data instead of regular screen characters.

This explains what you are seeing on the screen.
the Square symbol is character value 0, which means that character cell is supposed to reference PCG bank 0.

An earlier version of the boot disk (made for non-premium machines) would be better to run on your system.
Great work in getting the machine going.