Nov 042018
 

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.

 

P.S.

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:

 

 Posted by at 2:56 pm

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