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I have a Tetris (5358) System 16b board with a suicided FD1094. I was looking into the process of replacing the FD1094 with a 10mghz 68000 and doing the necessary steps to convert it to an unencrypted Alien Syndrome, and I wanted others opinions on the process to make sure I understand it correctly.
From what I gather looking at the following 2 sites....
www.arcade-projects.com
&
replacing the FD1094 with a 10mghz 68000
only additionally requires replacing the encrypted roms with unencrypted (unprotected) roms, so in my case of converting to alien syndrome, I need a full set of 256kbit 27C256 and 512kbit 27C512 eproms and then move the jumpers and install the eproms in the correct positions as in this photo of a alien syndrome 5358 board...

One thing I don't understand however is this part of the converting process from arcade-projects...
"The main program ROMs (A5 and A7) have to be non JEDEC 1mbit EPROMs (unless the game uses a 512kbit EPROM) - 27C1000 or 27C301 are the type you will require. The other ROMs are all JEDEC type"
Any additional input would be greatly appreciated!
From what I gather looking at the following 2 sites....
System 16B Conversion Help
Hi guys, I've done a bit of work converting games on the System 16B hardware and learned a lot along the way. A couple of people have asked for some help with conversions and @ekorz suggested it would be nice to have a thread here - so I wanted to provide all the information I can on the topic...
&
replacing the FD1094 with a 10mghz 68000
only additionally requires replacing the encrypted roms with unencrypted (unprotected) roms, so in my case of converting to alien syndrome, I need a full set of 256kbit 27C256 and 512kbit 27C512 eproms and then move the jumpers and install the eproms in the correct positions as in this photo of a alien syndrome 5358 board...

One thing I don't understand however is this part of the converting process from arcade-projects...
"The main program ROMs (A5 and A7) have to be non JEDEC 1mbit EPROMs (unless the game uses a 512kbit EPROM) - 27C1000 or 27C301 are the type you will require. The other ROMs are all JEDEC type"
Any additional input would be greatly appreciated!
