TRS-80 Model I EI question

From: Allison J Parent <>
Date: Tue Jul 15 20:45:01 1997

<I'm trying to track-down a mod that Tandy on the Expansion Interface. On o
<of my early EIs (SN# 000352), there was a 6-pin DIN modification, which
<someone at one time told me was to correct some erratic signal problems.

the mod was to bring out ras* cas* and MUX* with terminating resistors at
one or both ends. These signals went through the EI cable but timing was
critical at best. the later EIs derived cas* and mux* off of ras* inside
rather than pipe them over. Generally speaking the mod was one where if it
was mostly working it MIGHT help, sometimes it made it worse.

There was another mod after that called the buffered EI cable...not a good
idea either. Fixing the EI was the solution.

Received on Tue Jul 15 1997 - 20:45:01 BST

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