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FAULT: Board not booting up. Failing self check on VRAM

DIAGNOSIS Created a test Sequence for a known good VRAM (There are three in total on the board and one was failing). Ran the Test Sequence on the good VRAMs and both passed.

Running same Test on the bad one, flagged up pin 17 as faulty. Refused to pass test.

Tracing this pin showed it to be an address line that had no signal. Checking continuity showed that the pin should be connected to the 68000. It was open.


Soldered a wire link from the VRAM pin 17 to the 68000 pin. Board now boots into game. Still got sprite issues but now reliably booting up.