Monday, 4 September 2023

Irem 'KNA65005-17' reproduction

Another Irem custom IC has been defeated and successfully reproduced.

After the 'KNA70H015(11)' and 'KNA70H016(12)'  

Irem 'KNA70H015(11)' and 'KNA70H016(12)' reproduction

I took into account the 'KNA65005-17', a DIP48 part found on M72 and later hardware like M81, M82, M84 and M85 (although with scratched-off part name)

The functions of this custom IC were reversed by analyzing and comparing the signals between original and bootleg hardware.As always I ended up with a prototype made with TTLs gates:

After some tweaking, it worked fine on all PCBs I could try.

Here's testing on R-Type (M72 hardware) and Dragon Breed (M82 conversion) 


 


Since the design has been validated a CPLD version of this TTL reproduction will follow later.And a full re-engineering of the entire Irem PCB is more possible now.

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