I own an Amiga 500 with a Kickstart 3.1 original chip. To preserve the original Chip I ordered "AMD 27C400-150" EPROMs and had the data contend of the original Kickstart-chip programmed onto a 27C400-EPROM.
Now, placing the EPROM onto my Kickstart-Switch makes no problem, it is working fine. But placing the EPROM directly into the ROM-Socket on the motherboard (Rev. 6a) results in permanent reboots / black screen. I doublechecked and veryfied; the EPROM`s content matches the Original 100%.
Well, what is that? Is the EPROM too slow? I guess not, since I heard of working EPROMs with a speed of -200. But why does it work in that Kickstart-switch (2 Kick-Sockets, one 74LS00-chip) but not stand-alone?
What could it be? Can I "heal" the problem or can I bin the EPROM? Anyone with an idea?