VT101 8085 CPU Fault

Matt Burke matt at 9track.net
Mon Jan 19 17:22:54 CST 2015

On 19/01/2015 21:45, Diane Bruce wrote:
> I'd suspect RAM since the ROM is (I assume) masked ROM.

The masked ROM could be faulty. My VT100 character generator ROM failed
with one of the data lines floating because (I think) one of the
internal wires had became detached from the die. I replaced it with an
EPROM but had to add a few jumper wires to the legs of the chip to get
the select lines in the right combination.


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