On 06/19/2020 02:02 AM, Tom Lake wrote:
I have an ADM-3A dumb terminal and when I first turn it on the display is squashed and the top line is mangled. After five minutes or so the display looks OK but is a little jumpy. After a few more minutes, the display is rock-solid and stays that way until the next time I turn it on cold. If I turn it off back on, the display is still fine as long as I don't let the ADM cool off first. Does anyone know what the problem might be? What to look for?

I agree with the others, caps are usually the culprit.
But don't waste time tracking down the individual component - that's for
modern hardware with the occasional failed cap. Old hardware like this
should be completely 're-capped'. That is, replace ALL the caps. Why?
because they degrade over time (especially electrolytics) and after a
few decades almost all of them will be due to fail soon. So just do it
now and get it over with.

-John G.