Model: SHVC-CPU-01
Symptom: Partial controller input
Diagnosis: Corrupted CPU memory
this unit responded only to some buttons from the first controller port, all the buttons on the second controller port worked.
Because the first controller reads some input, the data, strobe, and clock lines between the controller and CPU should be OK. The prime suspect was a corrupt CPU chip – since the state of the controller is read into CPU memory registers.
Out of curiosity, I swapped the CPU from this unit onto another motherboard (replacing a known bad CPU there). The same issue persisted with the chip on the new board – only partial controller input from port 1.
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