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Ok this could turn out to be an interesting fact, I have captured all 11 waveforms from A>L from the KLM596 schematic on my Tektronix scope including the said CPU RES6.5 without any midi hookup at all and it looks identical, this from my POLY800 KLM596-4 w/830236 eprom(1). The EX800 KLM596-7 also works with the same eprom(1) and same waveforms confirmed.
Now, and I'm just trying to figure out the EX800 issue, is it then that because the EX800 does not have a keyboard the 63B50 waits on a keyboard pulse thru RX_data first to send /IRQ pulse to CPU RES6.5? I'm pretty sure the RES6.5 is necessary as I can witness this on my POLY800 without any midi,
Is that the correct process for the EX800 ?
Because I did hook up a controller keyboard to the EX800 and got no sounds from it even after manually programming a few, that's when replaced some IC's and finally swapped eproms and confirmed the KLM596-7(EX800 & eprom(1)) was working fine in my Poly800. Then programmed 2 new EX800 #840206 eproms and still no sound and no RES6.5,
Tonight, I will put the Poly800 aside and concentrate on the EX800 pulses,
I'm pretty sure its not the eprom but something has to give..