Restoring a VT50 (VT52 actually) .

Fritz Mueller fritzm at
Sat Dec 23 03:08:23 CST 2017

Hi Mattis,

> On Dec 23, 2017, at 12:08 AM, Mattis Lind via cctalk <cctalk at> wrote:
> Anyhow, the VT52 boards are dead. … The terminal uses 4 pieces
> of 256 by 4 bipolar PROMs for a total of 512 bytes of microprogram.
> Has anyone dumped the contents of these so I could verify them?

I have a restored VT52.  Taking a peek, I see these PROMs are socketed, so I can pull mine this weekend and give them a read for you no problem.

I actually had a lot of trouble with a flaky oscillator when I was working through my VT52, but it sounds like your’s is going fine if you are observing the whole timing chain including video sync?


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