Received for repair this original The New Zealand Story PCB (one layer hardware revision)
Board played fine except for this issue concerning background graphics, they had jail bars though :
All GFX data are stored in eight 1Mbit 28 pin MASK ROMs :
I dumped them starting from the one on the right labeled ‘B53-01’ :
And my programmer complained about a bad contact of pins 18-19 (which are data lines)
As said the device is a 1Mbit 28 pin MASK ROM which no direct replacement exist of, the only option is to adapt a 1Mbit 32 pin EPROM (better with non-JEDEC pinout), that’s what a made :
Perhaps not the best looking solution but it fixed board completely.Job done.
This repair inspired me so I made my own design to adapt a 1Mbit 32 pin TSOP Flash ROM to the 28 pin 1Mbit MASK ROM pinout: