IBM 5151 (MDA display) - common faults / gotchas?

drlegendre . drlegendre at
Tue Nov 11 17:03:39 CST 2014

Persistence is directly related to beam intensity.. does it still linger so
long when its dimmed down?

Otherwise, I don't see any way for the phosphor chemistry to change much
over time, being hermetically sealed up in there. If anything, I'd expect
persistence to +diminish+ with age, as the materials deplete (if such
action occurs).

But like most chemical / physical processes, temperature may well have a
notable effect. Longer persistence when cold would make sense, in that

On Tue, Nov 11, 2014 at 4:42 PM, Ali <cctalk at> wrote:

> > I'd forgotten about the long persistence phosphor in the CRT until Tony
> > mentioned it - is it highly temperature-dependent
> It does take a very long time although 20 seconds seems a bit extreme. The
> first time I turned one on after not having used one for over a decade I
> was
> surprised as well.
> -Ali

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