Purchased recently a untested rygar bootleg pcb from ALPHA, gave me a good price for it.The pcb was not tested due to a weird jamma adapter fitted with a 36 pin finger pcb?the rgb connector on the rom board was soldered to the rgb,sync wires.
Also no spacers fitted, as tecmo was formerly known as tekhan,rygar uses the same jamma adapter as bombjack or star force so I used my star force adapter and powered on.....
Ok right, what we have is garbage on the screen but good news is we have rgb and sync but no sound at all.Went straight to the Z80cpu main on the top board and made some probing with the scope.there was a good clock signal, nmi high,int low,halt low,Rw low,reset toggling,data bus had random signals either high or low same as the address pins.Suspected a bad Z80cpu so I removed it and fitted a working z80b cpu,powered on and....
ok we have a change on the screens garbage as there's twitching in the graphics, the z80 is now trying to boot.the address pins are toggling, reset is high,halt high,rw toggling, nmi high but int is low, looking carefully on the data bus pins I found one data signal looking a bit flattened. Suspected a bad wram .
Removed this sram and fitted a new one and powered on...
Ohhhhhh yes!the game is now running but when I start playing rygar is all red Intermittently and there's garbage sprites which appear when destroying enemies?also after 10mins of playing there's green pixels appearing on sprites and background tiles.
To be continued...
Also no spacers fitted, as tecmo was formerly known as tekhan,rygar uses the same jamma adapter as bombjack or star force so I used my star force adapter and powered on.....
Ok right, what we have is garbage on the screen but good news is we have rgb and sync but no sound at all.Went straight to the Z80cpu main on the top board and made some probing with the scope.there was a good clock signal, nmi high,int low,halt low,Rw low,reset toggling,data bus had random signals either high or low same as the address pins.Suspected a bad Z80cpu so I removed it and fitted a working z80b cpu,powered on and....
ok we have a change on the screens garbage as there's twitching in the graphics, the z80 is now trying to boot.the address pins are toggling, reset is high,halt high,rw toggling, nmi high but int is low, looking carefully on the data bus pins I found one data signal looking a bit flattened. Suspected a bad wram .
Removed this sram and fitted a new one and powered on...
Ohhhhhh yes!the game is now running but when I start playing rygar is all red Intermittently and there's garbage sprites which appear when destroying enemies?also after 10mins of playing there's green pixels appearing on sprites and background tiles.
To be continued...
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