Check the schematic for the ROMs, I suspect you will find that pin 21 is
tied to ground. 2716's need that pin tied to +5. I hope that pin 21 is not
used as an active chip select, but I don't think so on this board. You can
"fix" this problem by bending the pin 21 out so it won't go into the socket
and adding a small jumper wire from it to pin 24. then plug them in and see
what happens.
John :-#)#
At 01:28 AM 05/02/2001, you wrote:
>Gang,
>
>My earlier post didn't come back to me so I don't know whether you got it or
>not however...
>
>Fixing my Space Wars one rom had most data lines held low - the second rom
>was fine.
>
>I burnt two 2716's and fitted them in sockets. However now neither rom has
>data lines working... in fact no signal on them at all. Address lines are
>fine.
>
>I have a feeling this is to do with the fact that they were masked roms, but I
>had no trouble replacing masked roms with 2716's before.
>
>Any idea how to get the roms to run?
>
>Thanks
>Paul
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