Televideo 925 character rom dump

Josh Dersch derschjo at
Tue Apr 23 11:38:03 CDT 2019

On Tue, Apr 23, 2019 at 8:25 AM Patrick Finnegan <pat at> wrote:

> On Tue, Apr 23, 2019 at 11:02 AM Jon Elson via cctalk <
> cctalk at> wrote:
>> Is the ROM totally bad, or just losing a few bits here and
>> there? If the latter, you could probably read it out, figure
>> out how the rows, columns and characters are mapped, and fix it.
> Considering that 925s are really common, and a replacement EPROM should be
> easy to source and program, this sounds like an overly difficult approach
> that will yield something different than what he wants.

The thought had crossed my mind, but only as a last resort.  I'm not
entirely sure what the internal fault is, but the end result is two rows of
every character have all bits stuck "on."  I've verified that the ROM
addressing is correct and that there's nothing on the output side causing
this behavior.  Patrick, thanks very much for offering to read the ROM!

- Josh

> Pat

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