Casio sk-5 tempo generation

[computer at sea]

Hey all,

Does anyone understand how the tempo is generated in the sk-5?  I can see the clock pulse on the percussion generation chip and the main CPU clock pulse.  I had hoped that increasing or decreasing the tempo would affect the percussion clock, but that would of course be to simple a solution.  I've scoped all around the area but have turned nothing up.

I suspect that this is a function that happens in the main CPU and is thus inaccessible, though I'd love for it to be not the case.  The tempo up and down buttons seem to lead there. 

What I want to do is extract a clock signal to power an external sequencer in sync with the preset rhythms, but I'm not making much headway.  Probably I could do some sort of perverse work around using filters and the kick drum hit, but for most rhythms I don't think I'd get a steady pulse.  Does anyone have any thoughts on this?  Wizard level peeps, please chime in.

[wax+wire]

All I know is that the tempo is also controlled by the main clock - and that there is a resistor that you can swap for a pot to tune the pitch of the percussion --- that is rad.