(gate array) TRS-80 Model 4 systems used a 1773 FDC, which was
Interesting. The older model 4s (like mine) have a 1793 -- the floppy
controller board is indentical to that in a model 3. I'd assumed they
used that board in the gate array versions as well.
Maybe they did (in the early gate array machines), and then changed to
the 1773 for the last ones. I don't see any reason why that couldn't have
been done -- as you said the 1773 and 1793 are pretty much compatible.
The early systems weren't gate array systems. The gate array Model 4
and 4P systems had the FDC and RS232 integrated on the mainboard. If
you have a separate FDC and/or RS232 board then your mainboard is not
a gate array model.
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