Re: Tek 7854 Doesn't Come On After EPROM ROM Replacement


Yes, the single new A28 memory board replaces both the old A28 RAM board and the
old A31 ROM board.

If I was replacing just the old ROM board and leaving the old RAM board in
place, this is where I would start although I can see that the decoding would
need to be changed to disable the output on RAM accesses. At the least,
comparing both schematics will be helpful in figuring out the memory map and
decoding. I have done that once but I did not keep any notes.

I am not aware of any differences in the firmware versions.

On 12 Jan 2014 13:19:51 -0800, you wrote:

So, this single board *replaces* the ROM *and* RAM board... ? The ROM and RAM boards in my 7854 could be replaced by this single board? That's pretty cool, if that's what you meant.


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