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caius

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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 differently 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 :




‘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 to 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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Wow! You did it again! Fantastic job.

A lot of PCBs can now be taken back to live again.
 
Alot of good stuff will be resolved with newest release from master Caius ✌️
 
What symptom(s) would a Shy Shark or Twin Cobra pcb exhibit if the GXL-02' was bad? I have both of these pcb's that give a blank screen upon boot-up. Would a faulty chip completely "kill" the pcb, or just give corrupted sprite graphics?
 
GXL-01 handles backgrounds and GXL-02 handles sprites, so if your GXL-2 was bad then you'd have backgrounds displaying but garbled sprites. I don't think a dead custom would cause the board to completely fail to boot - you'd probably still hear music and sound at least.

For black screen failure to boot symptoms, I suggest dumping your ROMs and comparing the checksums against MAME to make sure they're good, make sure the CPU is receiving a Clock pulse (logic probe the clock pin), make sure the CPU Halt pin isn't being asserted and check the CPU Work RAM traces and chips.
 
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