Jurassic Park - DMD Freezes

[andtan]

Hey Guys,

I've been trying to find the cause of some DMD issues with my Data East JP in which the DMD doesn't always work correctly.

Sometimes it will go blank, other times it will skip parts of the display sequences (after the boot up, or during gameplay), or at other times it will seem to hang - as if it is stuck. When it hangs it might be showing the score, but the score is still 'pulse' as part of the animation, but it just doesn't update anymore. The only way to get it working again is to turn the pin off and back on again. Just disconnecting, and reconnecting the power lead to the DMD doesn't always work.

I've checked the power - which seems fine, and changing the ribbons cables hasn't corrected the problem. Can someone tell me what other things I should be checking?

Cheers,

Andy

[beaky]

do you have another data east machine you can swap the display driver board with? if so swap the driver boards and display driver board roms and see if the problem moves to the machine you swapped the board to

also before doing this make sure there is no corrosion on the header pins that the ribbon cable connects to.

[robm]

Beaky is likely on the money, he suggested the same thing for my JP and it sorted it. I ended up very lightly hitting the header pins on the DMD with emery paper and the problem has disappeared

[andtan]

Thanks for the tip guys, I'll give them a try and see how it goes