The 'GXL-02' is a custom chip (in DIP42 package) found on most Toaplan arcade PCBs but you'll never encounter it with this part name but instead diffrently marked.Here's an overview:
"FDA MN53007T0A" on Hell Fire, Out Zone, Fire Shark :
‘TOAPLAN-02 M70H005" on Truxton/Tatsujin :
‘T.T-2’ on Twin Cobra/Kyuukyoku Tiger :
‘WT2’ on Wardner/Pyros :
‘L-02’ on Sky Shark/Hi Sho Zame :
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‘12.02’ on Rally Bike/Dash Yarou :
But, despite different labels, the silkscreening under the chip says always 'GXL-02' .
Unlike the 'GXL-01' (already reproduced by me Toaplan 'GXL-01' reproduction ) that generates backgrounds, the' GXL-02' handles sprites acting like a big counter.As usual, for my reproduction I took into account some bootlegs in order to study how the functions of this custom chip had been reversed by bootlegers.Unfortunately none of them was a complete TTLs implementtion of original chip but they gave me for sure hints on how the chip worked.
After some time spent adapting the designs from different bootlegs replacement boards I was able achieve a TTL prototype working for all games, here's testing on an Hell Fire PCB :
The next step was pretty easy since I had a valid design in my hands so I engineered a proper board that was as much compact as possible without the use of modern programmable logics (CPLD or FPGA) but simple surface mounted TTL gates.The result was pretty good :
The replacement worked fine on all PCBs I could try :
Hell Fire .
Out Zone :
Rally Bike :
Wardner/Pyros :
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