XVI mod for non-XVI models?

Started by DejahThoris, January 27, 2019, 12:54:01 PM

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DejahThoris

This is the second time on YAJ I've seen "Blue Line" or "Blue Switch" modified x68000's where there's a hole cut next to the Reset button and a switch installed to behave like an XVI, swapping between 10/16MHz presumably.

Are there any guides on how this is done?  I'm terribly curious, but not sure I'm not sure I'm throw-five-hundred-bucks-at-it curious, haha.

neko68k

#1
Basically you replace the oscillator. Before the XVI the MPU clock is 40mhz/4 = 10mhz. If you put in a 60mhz osc thats 60/4=15mhz. Of course it might not work. I think I remember the original and ace max at 12.5, pro at 15, expert at 17.5. The DMAC might not work at higher clocks. In my Pro it doesn't always work at 15mhz. The advice I got was to 1) cool it, 2) over volt it and/or 3) replace it with a 12.5mhz part which is not common.

[edit]
or clock the overall system slower, like 14.5 mhz instead of 15.