acorn atom and acorn system series • Atom memory issue

This is an Atom I acquired recently, and have been piecing back together. The poor thing had no space bar, and the keyboard surround was missing. An Electron spacebar is a reasonable fit, and a 3D printed surround is being temporarily used until I can find something more permanent.On boot this is the screen I get. As you can see, the A of Acorn is covered with a cursor. Anything I type is briefly flashed in this cursor, as well as appearing next to the prompt as expected. So I decided to run the Atomic Memory Checker, and this is what I get.I've got various spare ICs, so here is a list of what I have changed, none of which has made any difference.
IC51, IC52, IC22(6502), IC25(8255), IC31(VDG), IC42,IC43, IC27,IC28,IC29, IC30.

Has anyone got any ideas or recommendations on next steps. I'm not an expert, I can use a soldering iron, and I have a multimeter. No oscilloscope, and I wouldn't know how to use one if I did.

Thanks.

Statistics: Posted by MartinCummings — Fri Nov 07, 2025 8:44 pm

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