PET mono screens

Adrian Graham binarydinosaurs at
Tue Oct 27 09:38:11 CDT 2015

On 27 October 2015 at 13:33, tony duell <ard at> wrote:

> By 'CRT' I assume you mean the evacuated glass thing. The term is alas also
> misused to mean 'monitor'

Indeed, the glass thing.

> Before you go to all that trouble, why do you think it has failed? In all
> my time of working
> on classic computers I've had exactly one mono CRT fail (and no colour
> ones). Fail meaning
> 'gives nothing on the screen' -- I've had a few with phosphor burn, or
> with low emission. But
> those gave an image, albeit a dim one.

Purely because not only do I get nothing on screen but if I turn both the
brightness and sub-bright up full I can't see any glow or raster lines.
I've got at least 3 monitor 'units' that do this, one of them also smokes
but we'll leave that one for now, I guess it's old enough :)

The PSU is giving 22VAC for the screen and the monitor pins on the
motherboard give sensible voltages IIRC, The heater on one screen glows so
that's the one I'm using.

One problem at a time I guess, tonight I'll double-check the CRTC since I'm
assuming if that's dead I'll definitely not get even the garbage on screen.

Owner of Binary Dinosaurs, the UK's biggest home computer collection?

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