The problem is that the MUX isn’t being addressed correctly, but we don’t yet know why. For convenience, I’m repeating your earlier table.
I surmise the MUX address lines are A2,A1,A0 = 010. The state of these lines seems to be unchanged in both Tuner and Aux source selections; 010 corresponds to selection of the Tuner.
Below your table copied from post #17, I’ve posted a table arranged in a similar format showing the address lines as they should appear for the various sources. The second table has the same entries, cut with rows and columns transposed, easier to read I think. The mystery is why the data isn’t correctly presented on the MUX address pins. Please advise if this isn’t clear.
I haven’t been able to trace how the MUX address pins are sourced from the microprocessor. I see the MUX lines at the “SK100” connector on PDF page 16, same page as the Z104/Z105 ICs. But where do the signals go from there? I’m probably being blind. Thanks for guiding me.
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